Resources · Glossary

The EV charging glossary

200 EV charging terms, acronyms, standards and technologies explained clearly by engineers who design EV charging systems.

From OCPP, ISO 15118 and Plug & Charge to load balancing, G100, connectors, batteries and V2G, find concise definitions for the terminology used across EV charging hardware, software and infrastructure.

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Browse the full glossary A to Z, or filter by technical category.

A

A/C

Glossary A/C A/C means air conditioning, the vehicle system used to cool and dehumidify the cabin. In an EV, climate control is powered from the electrical energy available to the vehicle rather than by mechanically driving a compressor from an engine. Air-conditioning demand can reduce driving range because it adds to the vehicle's energy consumption. A/C should not be confused with AC, meaning alternating current in electrical engineering.

EV & Vehicle Terminology

AC

Also called: alternating current AC means alternating current, an electrical current that periodically reverses direction. Electricity distribution systems supply AC, which is why most home, workplace and destination charge points deliver AC to the vehicle. An EV battery stores DC energy. During AC charging, the vehicle's onboard charger converts the incoming AC into controlled DC for the battery. AC charging power depends on the supply, EVSE and onboard charger. In Europe, a Type 2 connection can support single-phase or three-phase AC charging where the installation and vehicle are designed for it.

Charging & Electrical Engineering

AC and DC charging

AC and DC charging differ mainly in where the electrical power is converted into the DC needed by the vehicle battery. With AC charging, the vehicle's onboard charger performs the conversion. With DC charging, the main conversion takes place in the external charging equipment. Moving the power electronics off the vehicle allows DC equipment to be built for much higher charging power than a typical onboard charger, although the vehicle still sets the power it can safely accept. AC or DC describes the electrical form of the power delivered at the vehicle interface. It does not by itself tell you the exact connector, charging speed or communication protocol.

Charging & Electrical Engineering

Ad hoc charging

Also called: ad hoc access, ad hoc payment Ad hoc charging lets a driver use and pay for a public charge point without having a pre-existing contract with the operator. It gives occasional users access without requiring a subscription, RFID account or membership of that charging network. Contactless bank-card payment is one route to ad hoc charging. Other methods can be offered as well, provided the applicable legal requirements are met. In the UK, contactless payment covered by the Public Charge Point Regulations must be available on an ad hoc basis. A customer cannot be required to enter a contract before using that contactless option.

Payments, Roaming & Authentication

AFIR

Also called: Alternative Fuels Infrastructure Regulation, Regulation (EU) 2023/1804 AFIR is the European Union regulation setting deployment and operating requirements for publicly accessible alternative-fuels infrastructure, including EV charging. It applies directly across EU Member States. For EV charging, AFIR covers matters including network rollout, ad hoc access, payment, pricing transparency, interoperability and charging-infrastructure data. Publicly accessible charge points deployed from 13 April 2024 must support ad hoc charging using specified widely used payment methods. AFIR also sets infrastructure targets along the TEN-T network. Manufacturers and CPOs serving the EU therefore need to consider both equipment interoperability and operator-facing obligations.

Standards, Safety & Compliance

Agreed export capacity

Also called: AEC, agreed capacity for export Agreed export capacity is the level of electrical export permitted at a customer's connection to the distribution network. It matters where a site can send power back through the connection from generation, battery storage or bidirectional EV charging. The exact contractual terminology can vary by network operator. The practical engineering requirement is to keep export within the limit agreed for the connection. A G100 export-limitation scheme can be used where the DNO agrees that export must be controlled rather than allowing the connected equipment's unconstrained maximum.

Grid & Energy Management

Agreed import capacity

Also called: AIC, agreed capacity for import Agreed import capacity is the maximum level of power a site's connection agreement allows it to import from the electricity distribution network. It is one of the key constraints used when assessing how much new electrical load a site can support. EV charging can push a site closer to this limit because many charge points may operate at the same time as existing building loads. Increasing connection capacity can require DNO approval and, in some cases, network reinforcement. Load balancing or an approved limitation scheme can sometimes allow more charging infrastructure to be installed while keeping actual site import within the agreed boundary.

Grid & Energy Management

Alternative fuel vehicle

Also called: AFV An alternative fuel vehicle is a broad term for a vehicle using a fuel or powertrain other than a conventional petrol or diesel-only drivetrain. The exact vehicles included depend on the policy, dataset or scheme using the term. EVs, plug-in hybrids, hydrogen vehicles and some other fuel technologies can all appear under AFV classifications. Because AFV is broad, use the specific vehicle type where charging or infrastructure requirements matter.

EV & Vehicle Terminology

Autocharge

Autocharge is a method of automatically identifying and authorising an EV from an identifier supplied by the vehicle, commonly its charging-interface MAC address. Once that identifier has been linked to a driver's account, a compatible network can recognise the vehicle when it is plugged in. Autocharge and Plug & Charge produce a similar driver experience, but their security models are different. Plug & Charge uses certificates and PKI defined around ISO 15118, while Autocharge commonly relies on an identifier that is not a cryptographic proof of identity. That distinction matters when designing authentication, roaming and fraud controls. CharIN guidance does not regard a CCS MAC address alone as secure authentication.

Payments, Roaming & Authentication

Autopilot

Tesla Autopilot is the brand name used for a set of driver-assistance functions rather than a fully autonomous driving system. Functions and availability vary by vehicle, software version and market. Tesla's current driver-assistance documentation includes functions such as Traffic-Aware Cruise Control and Autosteer. The driver remains responsible for supervising the vehicle and complying with the operating instructions. Autopilot is not an EV charging technology; this page is retained because it is established EV terminology and has historical search visibility.

EV & Vehicle Terminology

Availability

EV charger availability describes whether an EVSE is in a state that allows a driver to use it for charging. In connected charging networks, availability is normally represented through status data rather than inferred only from whether the cabinet has power. A charger can be unavailable because it is occupied, reserved, out of service, faulted or otherwise unable to accept a new session. The exact status vocabulary depends on the protocol and platform. Availability data is important for drivers and operators, and UK public-charging regulations require specified availability data to be accurate and made available through the mandated open-data framework. B

Operations & Infrastructure

B

B2U

Also called: battery second use B2U means battery second use, the reuse of an EV traction battery in another application after it leaves its original vehicle role. Stationary energy storage is a common second-use application because weight and packaging constraints are less severe than in a vehicle. A battery can leave automotive service while retaining useful capacity for a less demanding duty. Reuse can extend the service life of the pack before material recycling. B2U should not be confused with remanufacturing or recycling. Those are different end-of-first-life routes.

Battery & Energy Storage

Battery

An EV battery stores electrical energy electrochemically and supplies DC power to the vehicle's electric drivetrain and other systems. A traction battery is built from cells combined into modules or pack structures with monitoring, protection and thermal management. Most current battery-electric vehicles use lithium-ion chemistries, although the exact cell materials vary. Battery capacity is measured as energy, normally in kWh. The battery-management system controls allowable charging and discharge conditions based on measurements such as voltage, current and temperature.

Battery & Energy Storage

Battery capacity

EV battery capacity is the amount of electrical energy a battery can store, usually stated in kilowatt-hours. Capacity is an energy quantity, so it should not be expressed in kilowatts, which measure power. Manufacturers may publish gross capacity and usable capacity. Gross capacity describes the total designed energy content, while usable capacity is the portion the vehicle allows the driver to access within the battery-management limits. A larger capacity can support more driving range, but range also depends on vehicle efficiency, speed, temperature and auxiliary loads.

Battery & Energy Storage

Battery cells

Battery cells are the individual electrochemical units that store and release electrical energy inside an EV battery pack. Cells are connected electrically and mechanically to achieve the voltage, capacity and power required by the vehicle. EV cells are commonly manufactured in cylindrical, prismatic or pouch formats. The format describes the package shape rather than the battery chemistry. A battery pack can contain hundreds or thousands of cells, with sensors and a BMS used to keep operation within safe limits.

Battery & Energy Storage

Battery degradation

Battery degradation is the gradual loss of usable energy or power capability as a battery ages through time and use. In an EV, degradation can reduce driving range and alter the power the battery can deliver or accept. Battery ageing comes from both calendar ageing and cycling. Temperature, time spent at high or low state of charge, charge and discharge rates, cell chemistry and usage history all affect the rate of change. Rapid charging is one influence rather than a universal single cause. Its effect depends on the cell design and the charging conditions, including temperature and the C-rate applied.

Battery & Energy Storage

Battery Energy Storage System

Also called: BESS, battery storage system A Battery Energy Storage System, or BESS, stores electrical energy in batteries so it can be used later. A complete BESS normally includes battery packs along with power conversion, control, protection and thermal-management equipment. At an EV charging site, a BESS can reduce grid import during peak charging demand, store on-site generation or shift energy use between time periods. The value depends on the site's electrical limits, tariff structure and operating pattern. A BESS is a separate asset from the EV batteries themselves, although both can take part in site energy management.

Battery & Energy Storage

Battery lease

A battery lease separates ownership of an EV battery from ownership of the vehicle, with the driver paying a recurring charge to use the battery. The battery provider retains ownership and the contract can include battery-health guarantees. Early EVs such as some Renault Zoe models were sold under this model to lower the vehicle's purchase price and reduce the buyer's battery-degradation risk. Battery leasing is much less common on current passenger EVs, but it still matters when valuing or buying used vehicles that were originally supplied with a separate battery contract.

EV & Vehicle Terminology

Battery management system

Also called: BMS A battery management system, or BMS, monitors and protects a battery pack while calculating the limits within which it can charge and discharge safely. It measures battery conditions and uses those measurements to manage operation. In an EV, the BMS can monitor cell or pack voltage, current and temperature, estimate state of charge and state of health, manage thermal conditions and set charging limits. During DC charging, the vehicle uses battery information to tell the charging system what voltage, current or power it can accept. That limit can change throughout the session.

Battery & Energy Storage

Battery preconditioning

Battery preconditioning heats or cools an EV battery towards a target temperature before a demanding operating condition such as high-power charging. The vehicle uses its thermal-management system to move the battery closer to the temperature range where it can perform effectively. A cold or very hot battery can accept less charging power than the same battery at a favourable temperature. Preconditioning before a DC charging stop can therefore improve the charging curve. The feature does not increase the battery's capacity. It changes the battery condition so the BMS can permit more suitable power within its limits.

Battery & Energy Storage

Benefit in Kind

Also called: BIK, company car tax Benefit in Kind is the UK tax treatment applied when an employer provides a company car that is available for private use. The taxable amount depends on the car's list price and the appropriate percentage set for its emissions and, for some low-emission cars, electric range. For the 2026/27 tax year, the appropriate percentage for a zero-emission company car is 4%. Rates are scheduled to change over time, so the current percentage should always be dated. BIK is a tax rule rather than an EV grant. Its historically lower percentage for zero-emission cars has been one reason electric company cars can have lower taxable benefit than many combustion vehicles.

Standards, Safety & Compliance

BEV

Also called: battery electric vehicle, pure electric vehicle A battery electric vehicle, or BEV, is propelled only by electric motors using energy stored in an onboard battery that can be charged from an external electricity supply. It has no petrol or diesel engine providing propulsion. BEVs produce zero tailpipe CO2 while driving. That describes vehicle operation at the tailpipe rather than the full lifecycle emissions associated with manufacturing and electricity generation. BEVs rely on external charging, so charging speed depends on the vehicle's AC and DC capabilities as well as the charging equipment.

EV & Vehicle Terminology

Bidirectional charging

Bidirectional charging allows electrical energy to flow both into an EV battery and back out through compatible charging equipment. The exported energy can be used by a home, building, local load or electricity network depending on the system design. ISO 15118-20 defines communication messages and sequences for bidirectional power transfer. The vehicle, EVSE, electrical installation and grid connection must all support the intended use case. Bidirectional capability at the charger does not automatically permit export to the public network. Grid-connection requirements, including G99 and G100 where applicable in Great Britain, still need to be satisfied.

Grid & Energy Management

BS 7671 Section 722

BS 7671 Section 722 contains the UK wiring requirements that apply specifically to supplies for electric vehicle charging installations. It sits within BS 7671, the national standard for low-voltage electrical installations used in domestic, commercial and industrial settings. Section 722 covers EV charging installation matters such as protective measures, RCD protection and earthing arrangements. It is used alongside the general requirements elsewhere in BS 7671 and relevant EVSE product standards. BS 7671:2018+A4:2026 was published on 15 April 2026. The previous Amendment 3 version remains valid during the transition period until 15 October 2026, after which Amendment 4 must be used.

Standards, Safety & Compliance

Building Management System

Also called: BMS, Building Automation System (BAS) A Building Management System, or BMS, is a hardware and software platform used to monitor and control a building's mechanical, electrical and other operational systems. Typical BMS functions include monitoring and control of HVAC, lighting, power systems, metering, fire protection and security. In an EV charging installation, a BMS can exchange site-demand, metering or operating data with charging and energy-management systems. This allows EV charging to be coordinated with building loads, local generation, battery storage or other site constraints. Modern BMS platforms can integrate EV charging and microgrid data as part of wider energy management. The acronym BMS also means Battery Management System in EV and battery engineering. The context matters: a Building Management System manages building services and site systems, while a Battery Management System monitors and protects a battery pack. C

Grid & Energy Management

C

C-rate

C-rate expresses battery charge or discharge current relative to the battery's rated charge capacity. A rate of 1C means a current numerically equal to the battery's ampere-hour capacity, while 0.5C is half that current and 2C is twice it. The notation gives engineers a way to compare charging stress across batteries of different sizes. A 100 Ah battery charged at 100 A is at 1C, while the same current applied to a 200 Ah battery is 0.5C. C-rate is not the same as charger power in kW. Voltage and battery size both affect the power corresponding to a given C-rate.

Battery & Energy Storage

CAN bus

CAN bus is a serial communications network that lets electronic control units exchange short, prioritised messages without a central host computer. It is widely used inside vehicles and embedded equipment because it is designed for reliable real-time control. In EV charging hardware, CAN can connect controller boards to power modules, meters, displays or other local devices. It is an internal or site-level interface rather than a replacement for OCPP, which normally connects a charging station to a management system. CAN now exists in several forms. Classic CAN supports data fields up to 8 bytes, while CAN FD and CAN XL increase payload size and data rate.

Protocols & Communications

Car club

A car club gives members short-term access to shared vehicles without requiring each user to own the car personally. Vehicles are booked for individual journeys and returned according to the operator's model. Electric car-club fleets need reliable charging access at vehicle bases or across their operating area. The term describes a mobility-service model rather than an EV technology.

EV & Vehicle Terminology

CHAdeMO

CHAdeMO is a DC fast-charging system with its own vehicle connector and communication protocol. It was developed in Japan and has been used by vehicles including earlier Nissan and Mitsubishi electric models. CHAdeMO is standardised within the IEC 61851 and IEC 62196 families. It also supported bidirectional charging early in the development of commercial vehicle-to-grid systems. The specification is still being developed. CHAdeMO 2.1 was released in May 2026 and raises the specified charging current to 800 A, with support for Plug & Charge functions among the changes. The installed public network still includes many chargers built to earlier CHAdeMO versions.

Connectors & Charging Modes

Charge flap

Also called: charge port door, charging port cover A charge flap is the vehicle body cover over the charging inlet. It protects the inlet area when the vehicle is not connected to charging equipment. Inlet position varies between vehicles. That affects cable reach, parking orientation and the usability of bays where the charging cable is short or fixed. The flap itself is not the charging connector. The connector is on the cable and mates with the vehicle inlet behind the flap.

Connectors & Charging Modes

Charge Point Operator

Also called: CPO A Charge Point Operator, or CPO, is the organisation responsible for operating EV charging infrastructure and the associated charging service. In UK public-charging regulation, the CPO is the person responsible for operating the public charge point, whether as owner or on behalf of another party. CPO responsibilities can include charger monitoring, maintenance, tariffs, payment, customer support, roaming and open-data publication. A CPO is a different role from an eMSP. The CPO runs charging infrastructure; the eMSP manages a charging service or contract used by drivers across one or more networks.

Operations & Infrastructure

Charging capacity

Charging capacity is an ambiguous phrase that can refer to battery energy capacity, charger power or the electrical capacity available at a site. Those are different engineering quantities and should be named explicitly. Battery capacity is measured in kWh. Charger power is measured in kW. Site capacity describes the electrical power or current that the installation and grid connection can support. Where an older document says only "charging capacity", check which of these meanings is intended before comparing specifications.

Charging & Electrical Engineering

Charging curve

An EV charging curve shows how charging power changes during a charging session. It is usually plotted against time or state of charge and explains why a vehicle does not hold its headline peak charging power from empty to full. The vehicle's battery-management system changes allowable charging power as state of charge, battery temperature and other limits change. The EVSE can also impose its own voltage, current or power ceiling. Two vehicles connected to the same DC charger can therefore produce very different charging curves and total charging times.

Battery & Energy Storage

Charging Detail Record

Also called: CDR, Charge Detail Record A Charging Detail Record, or CDR, is the final billing record for a completed EV charging session. In OCPI, it is the billing-relevant object created by the CPO and sent to the eMSP after the session ends. A CDR can contain the charging location, EVSE, tariff, energy used and the total cost. It preserves the information that applied to that session rather than changing when location or tariff data is updated later. The CDR is separate from the live Session object. A Session changes while charging is in progress; a CDR records the concluded transaction.

Payments, Roaming & Authentication

Charging point

A charging point is a physical device used to recharge an electric vehicle. Depending on its design, one physical charge point can contain one EVSE or several independently managed EVSEs. This distinction matters where a cabinet can charge more than one vehicle at the same time. UK public-charging guidance records those simultaneously usable positions as separate EVSE objects even though they sit in one physical unit. "Charge point", "charger" and "charging station" are often used loosely in everyday language. For technical data, use the physical charge point, EVSE and connector terms consistently.

Operations & Infrastructure

Charging rate

Charging rate describes how quickly an electric vehicle receives energy, usually expressed as charging power in kilowatts or as range added per hour. The actual rate during a session is limited by the charge point, the vehicle and current battery conditions. During AC charging, the vehicle's onboard charger sets an important upper limit. During DC charging, the onboard AC charger is bypassed and the vehicle communicates the power it can accept from the DC charge point. Charging rate is rarely constant from empty to full. Battery temperature and state of charge affect the charging curve, so a 150 kW charge point does not mean the vehicle will take 150 kW throughout the session.

Charging & Electrical Engineering

Charging station

A charging station is a broad term for EV charging equipment or a location containing charging equipment. Its precise meaning depends on the technical standard, operator platform or everyday context in which it is used. In OCPP 2.x, Charging Station is a defined system object managed by a CSMS and can contain multiple EVSEs. In everyday public-charging language, "station" can also mean the wider site. When specifying products or data interfaces, use the definition belonging to the relevant protocol rather than assuming every platform uses "station" in the same way.

Operations & Infrastructure

Cheetah stance

Cheetah Stance is Tesla's name for the suspension position used during the launch sequence in Drag Strip Mode on compatible Model S vehicles. The front suspension lowers before launch, reducing ground clearance. Tesla's current Model S manual still uses the "Cheetah Stance Enabled" message as part of the launch procedure. It is a Tesla-specific performance feature rather than a general EV engineering term.

EV & Vehicle Terminology

CO2

CO2 is carbon dioxide, a greenhouse gas released when carbon-containing fuels are burned. Road-vehicle policy uses tailpipe CO2 in emissions testing, taxation and vehicle classifications. Battery electric vehicles produce no tailpipe CO2 while driving because they do not burn petrol or diesel onboard. Tailpipe CO2 is not the same as lifecycle greenhouse-gas emissions, which can include vehicle manufacturing and energy production.

EV & Vehicle Terminology

Combined Charging System

Also called: CCS, Combo charging system The Combined Charging System, or CCS, combines AC and DC charging around a shared vehicle inlet and a common charging architecture. In Europe, CCS uses Type 2 for AC charging and Combo 2 for DC charging. In North America, the corresponding legacy CCS configuration uses Type 1 and Combo 1. CCS covers more than the connector shape. The system brings together charging control, power transfer and communication standards, including IEC 61851 and ISO 15118 or DIN SPEC 70121 for higher-level DC communication. IEC 62196-3:2026 is the current IEC standard for high-power DC and combined AC/DC vehicle couplers, including the connector configurations used by CCS.

Connectors & Charging Modes

Commando socket

Commando socket is a common UK trade name for an IEC 60309 industrial plug and socket. IEC 60309 connectors are rugged, keyed industrial connections available in several voltage, current and phase configurations. They are not inherently three-phase. Single-phase blue IEC 60309 sockets and three-phase red versions are both common. Industrial sockets can supply portable or specialist EV charging equipment where the electrical installation is designed for it, but the socket alone does not provide the control and protection functions of EVSE.

Connectors & Charging Modes

Commissioning

EV charger commissioning is the process of configuring, testing and verifying installed charging equipment before it is handed over for operation. It confirms that the charger, electrical installation and connected services behave as intended. Commissioning can include electrical checks, charger configuration, network connectivity, OCPP connection, payment or RFID tests, load-management setup and confirmation that remote monitoring works. A structured commissioning record reduces later troubleshooting because installers and support teams know which settings, firmware versions and site measurements were present at handover.

Operations & Infrastructure

Connector

An EV charging connector is the cable-end interface that mates with the vehicle inlet to transfer electrical power and charging signals. The connector is the movable part at the end of the charging cable. The matching inlet is fixed to the vehicle. Connector design determines which vehicles and charging systems can mate physically. The electrical and communication functions then depend on the wider charging standard, such as IEC 61851, SAE J1772, CCS or CHAdeMO. In standards work, "connector" and "inlet" are not interchangeable terms. Keeping that distinction matters when specifying cables, sockets, replacement parts or interoperability tests.

Connectors & Charging Modes

Connector type

Connector type identifies the physical charging interface used between an EV and charging equipment. Common examples include Type 2 for AC charging in Europe, CCS Combo 2 for European DC charging, CHAdeMO on part of the installed fleet, and SAE J3400 in North America. Connector type affects physical compatibility, but it does not describe the whole charging system. Charging mode, supported power, communication method and regional standards also determine whether a vehicle and charge point can work together. For product specifications, name the connector standard and the charging capability rather than relying on a broad label such as "fast charger".

Connectors & Charging Modes

Contactless payment

Contactless payment lets an EV driver pay for public charging with a contactless bank card or compatible payment device without first opening an account with the Charge Point Operator. The payment terminal can be built into the charge point or serve several nearby charge points at the same charging site. UK regulations require contactless payment at all public charge points rated 50 kW and above. They also require it on new public charge points rated 8 kW and above that were deployed after 24 November 2024, subject to the exemptions in the regulations. Contactless payment is an ad hoc payment method. It can sit alongside apps, RFID cards and roaming services.

Payments, Roaming & Authentication

Control pilot

Also called: CP, PWM control pilot The control pilot is the basic signalling circuit between an EV and EVSE used to indicate charging state and the current the EVSE can make available for AC charging. IEC 61851 defines the control-pilot function. In AC charging, the EVSE uses a pulse-width-modulated signal to communicate its available current. The vehicle changes the electrical state of the pilot circuit to indicate connection and charging readiness. High-Level Communication can operate alongside this basic signalling where richer digital communication is required. The control pilot and ISO 15118 therefore solve different layers of the charging-interface problem.

Protocols & Communications

Cost per kWh

Cost per kWh is the price charged for each kilowatt-hour of electrical energy supplied during an EV charging session. It lets drivers compare the energy component of charging prices across networks and locations. UK Public Charge Point Regulations require public-charging prices to be displayed clearly in pence per kWh before charging begins. A charging session can also involve parking, subscription or overstay charges, so the total session cost may include more than the energy price alone.

Payments, Roaming & Authentication

CPMS

Also called: Charge Point Management System, EV charging back office, charging back office A Charge Point Management System, or CPMS, is back-office software used to monitor, control and administer a network of EV charge points. Typical functions include charger status, remote commands, transactions, tariffs, users and reporting. CPMS is a common industry term for the same or a closely overlapping software category as a Charging Station Management System (CSMS). OCPP 2.x uses CSMS as its formal term, while OCPP 1.6 used Central System. “Back office” is the broader operational and commercial term commonly used for these platforms. The exact scope of a CPMS or back-office product varies by supplier. Some platforms extend beyond charger communications into billing, roaming, customer management, reporting and energy-management functions.

Operations & Infrastructure

CSMS

Also called: Charging Station Management System, EV charging back office, charging back office A Charging Station Management System, or CSMS, is the backend software platform that communicates with and manages EV charging stations. CSMS is the formal term used in OCPP 2.x. OCPP 1.6 used the term Central System for the equivalent backend role. In day-to-day EV charging, Charge Point Management System (CPMS) and EV charging back office are also commonly used for the same or closely overlapping software category. “Back office” can describe a broader product suite that includes billing, tariffs, user management, roaming and reporting as well as OCPP charging-station management. A CSMS can receive charger status and meter data, authorise users, manage transactions, change configuration and issue remote commands or firmware updates. The exact capabilities depend on the OCPP version and the software implementation.

Protocols & Communications

Current transformer

Also called: CT, CT clamp A current transformer, or CT, measures alternating current by producing a smaller proportional signal that monitoring or control equipment can read. It allows a load-management system to measure high site currents without routing the full load through the controller itself. In an EV charging installation, CTs are commonly fitted around incoming conductors or selected feeders so the control system can see how much current the site is drawing. That measurement can then be used to increase or reduce charging power. CT direction, ratio and location matter. If a CT is fitted to the wrong conductor, installed backwards or configured with the wrong ratio, the control system can make decisions using incorrect site-load data.

Grid & Energy Management

Customer Limitation Scheme

Also called: CLS A Customer Limitation Scheme is a control scheme that keeps electricity import or export at a customer's connection point within an agreed limit. Under ENA G100, a CLS can be used where new load or generation needs to be connected without allowing current at the connection point to exceed the agreed restriction. The scheme monitors relevant electrical conditions, normally using current and voltage measurements, and controls connected equipment when the limit is approached. On an EV charging site, that can mean reducing the power available to chargers rather than allowing the whole site to exceed its connection limit. A CLS is therefore broader than charger scheduling. Its job is to enforce the agreed boundary at the grid connection, including appropriate behaviour when measurements, communications or control components fail.

Grid & Energy Management

CVT

Also called: continuously variable transmission A continuously variable transmission, or CVT, changes drive ratio continuously rather than stepping through a fixed set of gear ratios. Conventional CVTs use mechanical arrangements such as variable-diameter pulleys or other ratio-changing mechanisms. Some hybrid vehicles use electrically controlled power-split transmissions that manufacturers describe as e-CVTs, although their internal design can differ substantially from a belt CVT. Most battery-electric vehicles do not need a multi-ratio CVT because electric motors can operate across a wide speed range with a fixed reduction gear.

EV & Vehicle Terminology

Cyber Resilience Act

Also called: CRA, Regulation (EU) 2024/2847 The Cyber Resilience Act is the EU regulation that sets horizontal cybersecurity requirements for products with digital elements placed on the European Union market. Connected EV charging hardware and software can fall within scope where the product meets the Act's definitions and no specific exclusion applies. Reporting duties began on 11 September 2026. Manufacturers must report actively exploited vulnerabilities and severe security incidents through the EU Single Reporting Platform, with an early warning required within 24 hours and fuller notification within 72 hours. The CRA's main product obligations apply from 11 December 2027. Those requirements cover the design, maintenance and vulnerability handling of products with digital elements through their support period. D

Cybersecurity & Firmware

D

DC

Also called: direct current, DC charging DC means direct current, electricity that flows in one direction and is the form of electrical energy stored by an EV battery. In DC charging, power-conversion equipment in the charge point converts incoming AC electricity to controlled DC before it reaches the vehicle battery. This arrangement avoids using the vehicle's onboard AC charger for the main power conversion. The charge point can therefore contain much larger power electronics than the vehicle normally carries for AC charging. The vehicle still controls how much power it can safely accept. Battery temperature, state of charge and the vehicle's own electrical limits can all reduce charging power below the charge point's maximum rating.

Charging & Electrical Engineering

Demand response

Also called: DSR, demand-side response Demand response changes electricity consumption in response to grid, market or price signals. EV charging is well suited to demand response because charging power and timing can often move without preventing the vehicle from being ready when it is needed. A demand-response event might reduce charging power during a constrained period, shift charging to another time or respond to a variable tariff. The control can be applied through an aggregator, energy-management system or charging platform. OpenADR is one open standard used for demand-response signalling. OCPP can then be used within the charging network to apply the required charger limits or schedules.

Grid & Energy Management

Depreciation

Depreciation is the reduction in a vehicle's market value over time. Age, mileage, condition, demand, supply, technology changes and the cost of comparable new vehicles can all affect the rate. EV depreciation is not determined by battery degradation alone. Battery condition matters, but used-EV values also respond to new-car pricing, charging capability, warranty terms and market demand. Depreciation affects total cost of ownership because the difference between purchase price and resale value can be one of the largest costs of keeping a vehicle.

EV & Vehicle Terminology

DER

Also called: Distributed Energy Resource A Distributed Energy Resource, or DER, is an energy asset connected within the distribution system rather than a large central generating plant. Depending on the context, DER can include solar PV, battery storage, controllable loads and bidirectional EV charging. DERs can change site import, export or both. Coordinating them matters on sites where chargers, BESS and generation share the same electrical connection. OCPP 2.1 introduced DER-control functions for charging-station integrations, reflecting the growing role of EV charging within wider site energy systems.

Grid & Energy Management

Destination charging

Destination charging provides EV charging at places where vehicles are already parked for a longer stay. Hotels, workplaces, leisure venues and long-stay car parks are common examples. Longer dwell time means destination charging often needs less power per vehicle than a motorway or rapid-charging site. The design question becomes how many vehicles can be served within the site's available capacity and parking pattern. Load balancing can increase the number of destination charge points that share a constrained supply by allocating power over the available dwell time.

Operations & Infrastructure

DIN SPEC 70121

DIN SPEC 70121 defines digital communication between a DC EV charging station and an electric vehicle for control of DC charging in the Combined Charging System. It predates widespread ISO 15118 implementation and remains relevant to the CCS installed base. DIN lists Edition 2 of the specification as published. The communication covers the DC charging control exchange between the vehicle and charging equipment. Newer CCS implementations increasingly use ISO 15118 for richer functions such as Plug & Charge and bidirectional power-transfer services, but compatibility with DIN SPEC 70121 can still matter when supporting existing vehicles.

Protocols & Communications

Distribution Network Operator

Also called: DNO A Distribution Network Operator, or DNO, owns, operates and maintains a regional electricity distribution network in Great Britain. DNOs connect homes and businesses to the distribution system, including new or enlarged electrical loads such as EV charging sites. A DNO is different from an electricity supplier. The supplier sells electricity to the customer, while the DNO is responsible for the local network infrastructure and the connection agreement. For larger EV charging installations, the DNO may need to assess the site's requested capacity, network constraints and any proposed import or export limitation scheme before the installation can operate as intended.

Grid & Energy Management

Dynamic load management

Also called: DLM, dynamic load balancing Dynamic load management adjusts EV charging power in real time using live site measurements so the electrical supply is not overloaded. It differs from a fixed charging limit because the available power can rise or fall as other site loads change. A typical system measures current or power at an agreed point in the installation, calculates how much capacity remains, then updates charger limits accordingly. This lets more charging capacity be used when the building is quiet while reducing EV demand when other loads increase. Dynamic load management can be implemented locally at the site or through a wider control architecture. For fast protection against site overload, local measurement and control normally matters more than cloud visibility alone. E

Grid & Energy Management

E

e-Pedal

Nissan e-Pedal is a driver-control feature that increases regenerative deceleration when the driver eases off the accelerator pedal. Current Nissan ARIYA models use the e-Pedal Step name. With e-Pedal Step active, returning the accelerator increases deceleration, but the driver must still use the brake pedal where the system cannot slow the vehicle sufficiently. The feature changes how regenerative braking is controlled; it does not increase the battery's underlying energy capacity.

EV & Vehicle Terminology

E-REV

Also called: extended-range electric vehicle, range-extended EV An E-REV is an extended-range electric vehicle that is driven electrically while carrying a combustion engine to generate additional electrical energy when required. The combustion engine acts primarily as a generator rather than the normal mechanical drive source. The term overlaps with REEV and range extender. UK vehicle classifications treat range-extended electric vehicles as a particular plug-in hybrid arrangement. E-REV should not be confused with a conventional HEV, which cannot normally be charged from an external electricity supply.

EV & Vehicle Terminology

Eco mode

Eco mode is a vehicle driving setting intended to reduce energy consumption by changing how selected systems respond. The exact behaviour is manufacturer-specific. An Eco mode can soften accelerator response, reduce heating or air-conditioning demand, or change other power-management settings. It does not create extra battery capacity. Any range benefit comes from lowering the vehicle's energy use.

EV & Vehicle Terminology

Economy 7

Economy 7 is a multi-rate electricity tariff with a lower off-peak electricity rate for a set number of hours and a different rate outside that period. The exact time window and prices depend on the supplier and meter arrangement. Overnight EV charging can make use of off-peak tariffs, although modern EV tariffs can use different time windows and pricing structures from traditional Economy 7. Smart charging can schedule charging into lower-cost periods without treating Economy 7 as the only form of time-of-use tariff.

Charging & Electrical Engineering

Eichrecht

Eichrecht is the German legal-metrology framework governing how measured quantities used for billing must be measured and presented. For public EV charging, it is concerned with ensuring that the energy measurement and resulting bill can be checked and trusted. Germany's national metrology institute, PTB, states that calibration law at public charging stations is intended to ensure correct measurement and billing. Eichrecht compliance involves more than fitting an accurate energy meter. The complete measurement and billing chain can matter, so product requirements should be checked against the current German metrology rules and applicable certification approach.

Standards, Safety & Compliance

Electric Highway

Electric Highway is a UK charging-network brand associated with charging at motorway service areas and other major-road locations. The network began under Ecotricity and was acquired by GRIDSERVE in 2021. It should not be used as a generic name for every motorway EV charging network. It refers to a particular commercial network and its historical development. The term remains useful because older articles, apps and drivers still use it when referring to the UK motorway charging estate.

Operations & Infrastructure

Electric Vehicle Homecharge Scheme

Also called: EVHS The Electric Vehicle Homecharge Scheme was a UK grant that supported the cost of installing domestic electric-vehicle charging devices from 2014 to 2022. It is closed to new applications. GOV.UK records 340,222 domestic charging-device installations funded under EVHS, with £140.8 million of grant support. The scheme was replaced by later Electric Vehicle Chargepoint Grant arrangements. EVHS remains useful as a historic term because older installer guidance and chargepoint purchase records still refer to it.

Standards, Safety & Compliance

eMSP

Also called: e-mobility service provider, mobility service provider, MSP An e-mobility service provider, or eMSP, provides EV drivers with access to charging services across one or more charge point networks. The eMSP normally owns the customer relationship and the charging contract or account used to authorise a session. In an OCPI connection, the eMSP receives charging-location and session data from the Charge Point Operator and can supply tokens or authorisation information in return. The eMSP then uses the Charge Detail Record for billing or settlement. An eMSP is a different market role from a CPO. One manages the driver-facing service while the other operates the charging infrastructure.

Payments, Roaming & Authentication

EV

Also called: electric vehicle EV means electric vehicle, although the term is used differently depending on context. In general discussion it can cover several electrified powertrains, including battery electric, plug-in hybrid and hybrid vehicles. UK vehicle statistics note that "electric vehicle" is a vague term and most commonly use it to mean a battery electric vehicle. Product specifications and regulations are clearer when they state the exact powertrain category. For charging infrastructure, the distinction matters because BEVs and PHEVs connect to external charging equipment, while conventional HEVs and MHEVs do not.

EV & Vehicle Terminology

EVCC

Also called: Electric Vehicle Communication Controller An Electric Vehicle Communication Controller, or EVCC, is the communication controller on the vehicle side of the ISO 15118 interface. It exchanges high-level charging messages with the Supply Equipment Communication Controller in the EVSE. ISO 15118 uses the EVCC and SECC relationship to establish IP-based communication for functions including charging control, identification and Plug & Charge. The EVCC is not the vehicle's battery-management system. It is the communication endpoint for the EV-to-EVSE protocol, although it exchanges information with other vehicle systems to complete a charging session.

Protocols & Communications

EVSE

Also called: Electric Vehicle Supply Equipment EVSE means Electric Vehicle Supply Equipment, the independently controlled part of a charge point that can supply energy to one electric vehicle at a time. A physical charge point can contain one EVSE or several EVSEs if it can charge more than one vehicle simultaneously. An EVSE can have more than one connector, although those connectors are alternatives for the same charging position and cannot all be used simultaneously. This distinction matters in public charging data, roaming and back-office systems because the physical cabinet, the EVSE and the connector are different objects. For AC charging, the EVSE controls the safe supply of AC power while the vehicle's onboard charger converts that power to DC for the battery. DC charging equipment performs the main AC-to-DC power conversion outside the vehicle.

Charging & Electrical Engineering

EVSE ID

Also called: EVSEID, EVSE identifier An EVSE ID is a structured identifier used to identify an individual EVSE across charging, roaming and billing systems. It identifies the EVSE, rather than every connector attached to it. The commonly used e-mobility format contains a two-letter country code, a three-character operator identifier, the letter E and an operator-defined identifier for the EVSE. Separators such as an asterisk can be used, for example GBABCE123456. In OCPI, the human-readable evse_id is separate from the EVSE's technical uid. An EVSE can also contain several connector objects, but only one of those connectors can be used by that EVSE at a time.

Protocols & Communications

F

Fast charging

Fast charging is a legacy UK label formerly used for EV charging above ordinary low-power charging but below rapid charging. The wording is still common in older articles and product descriptions. From 2026, UK Department for Transport statistics replaced the old "slow" and "fast" labels with Standard and Standard Plus. Standard Plus covers 8 kW to under 50 kW. Because industry terminology varies internationally, a kW rating is more precise than the word "fast".

Charging & Electrical Engineering

FCEV

Also called: fuel cell electric vehicle, hydrogen fuel cell vehicle A fuel cell electric vehicle, or FCEV, uses a fuel cell to generate electricity for the electric motor that propels the vehicle. Road-going FCEVs normally store compressed hydrogen onboard and combine it with oxygen from the air in the fuel-cell system. The vehicle has an electric drivetrain, but it is refuelled with hydrogen rather than relying on plug-in charging for its main energy supply. A small battery can buffer energy and recover power through regenerative braking. FCEVs have zero tailpipe CO2 under current UK vehicle classifications. The lifecycle emissions depend on how the hydrogen is produced and supplied.

EV & Vehicle Terminology

Firmware

EV charger firmware is embedded software stored on charge point hardware that controls how the device behaves and communicates. It can handle functions such as protocol messaging, hardware control, diagnostics and local configuration. Firmware sits close to the electronics, so an update can affect far more than the user interface. Changes can alter communications, security behaviour or how peripherals are controlled. Connected charge points therefore need a controlled firmware-update process. Version management, rollback planning and update authentication all affect field reliability.

Cybersecurity & Firmware

Flexibility

Also called: flex, demand flexibility Energy flexibility is the ability to change electricity demand or supply in response to site, grid, market or price conditions. EV charging is flexible when charging can move in time or change power without preventing the vehicle from meeting its required departure state. Flexibility can be used locally for load balancing or commercially through demand-response and aggregation services. Batteries and bidirectional vehicles can add further flexibility by changing both import and export. The old Versinetic glossary also used "Flex" for a former vehicle-finance or leasing label. That brand-specific meaning should be treated as historical rather than mixed into this energy-system definition.

Grid & Energy Management

Formula E

Formula E is the FIA world championship for all-electric single-seater racing. The series uses purpose-built battery-electric race cars and races on street and permanent circuits around the world. Formula E began racing in 2014. The GEN4 era starts in the 2026/27 season with cars capable of up to 600 kW in the championship's maximum-power mode. Formula E is motorsport rather than charging infrastructure, so it remains a low-priority glossary term.

EV & Vehicle Terminology

Fuel cell

A fuel cell converts chemical energy directly into electricity through an electrochemical reaction rather than combustion. In road vehicles, hydrogen fuel cells use hydrogen from the vehicle and oxygen from the air to generate electrical power. The electricity supplies an electric drivetrain, often with a battery used to buffer power and recover regenerative-braking energy. Fuel cells require a continuing fuel supply. They differ from batteries, which store energy internally and are recharged electrically. G

Battery & Energy Storage

G

G100

Also called: EREC G100, Engineering Recommendation G100 G100 is an Energy Networks Association engineering recommendation for customer import and export limitation schemes connected to Great Britain's electricity distribution networks. It applies where there is an agreed need to restrict current at the connection point or prevent distribution-network voltage limits being exceeded. The current document is EREC G100 A2 Issue 2, published in April 2023. Its scope includes new load as well as generation, which makes it relevant to EV charging sites where additional demand would otherwise exceed an agreed connection limit. A G100 arrangement can use a Customer Limitation Scheme to monitor conditions at the connection point and control relevant equipment so the agreed import or export limit is maintained.

Standards, Safety & Compliance

G98

Also called: EREC G98, Engineering Recommendation G98 G98 is an Energy Networks Association engineering recommendation for connecting fully type-tested micro-generators up to and including 16 A per phase in parallel with public low-voltage distribution networks in Great Britain. It also applies to electricity-storage devices within its stated scope. The current GB document is G98 A1 Issue 2, published in August 2026. It sets technical connection requirements in addition to the applicable requirements of EN 50549-1. G98 matters to EV charging projects when charging infrastructure is combined with small-scale generation or storage. Larger or different generating arrangements can fall under G99 instead.

Standards, Safety & Compliance

G99

Also called: EREC G99, Engineering Recommendation G99 G99 is an Energy Networks Association engineering recommendation setting technical requirements for generation equipment connected in parallel with public distribution networks in Great Britain. It covers Type A, B, C and D Power Generating Modules connected to licensed DNO networks. The current GB document is G99 Issue 2, published in March 2025. It is relevant to EV charging sites that also include generation, electricity storage or bidirectional export arrangements where the equipment falls within G99. G99 and G100 address different connection issues. G99 concerns generation connected in parallel with the network, while G100 covers agreed customer import or export limitation schemes.

Standards, Safety & Compliance

GHG

Also called: greenhouse gas GHG means greenhouse gas, a gas that absorbs and re-emits heat in the atmosphere. Carbon dioxide is the greenhouse gas most directly associated with fuel combustion in road transport. Lifecycle GHG analysis can include emissions from fuel or electricity production, vehicle manufacturing, operation and end of life. This is why "zero tailpipe emissions" and "zero lifecycle greenhouse-gas emissions" are different claims.

EV & Vehicle Terminology

Gigafactory

Gigafactory is an informal industry term for a very large manufacturing plant producing batteries, battery materials, electric vehicles or related components. It is a scale descriptor rather than a formal engineering standard. Tesla popularised the term, but it is now used more broadly across the battery and automotive industries. A gigafactory can contain cell production, module or pack assembly and other manufacturing processes depending on the site.

EV & Vehicle Terminology

Granny charger

Also called: Mode 2 cable, portable EV charging cable, three-pin charging cable A granny charger is a portable Mode 2 EV charging cable that connects an electric vehicle to a standard domestic socket. In the UK, Mode 2 charging from a BS 1363 socket usually operates at 10 A or less, which is roughly 2.3 kW at 230 V. The cable includes an in-cable control and protection device between the plug and the vehicle. That equipment provides the control-pilot function and electrical protection required for Mode 2 charging. A normal household socket can be used only where the socket and installation are suitable for EV charging. UK wiring guidance places additional requirements on socket-outlets intended for this use, so a granny charger should not be treated as a substitute for checking the electrical installation.

Connectors & Charging Modes

Guess-o-meter

Also called: GOM, range estimator Guess-o-meter is driver slang for the remaining-range estimate shown by an electric vehicle. The nickname reflects the fact that the predicted distance changes as the vehicle's energy consumption changes. A range estimator can use state of charge, recent efficiency, temperature, route or climate-control demand depending on the vehicle. The figure is an estimate rather than a direct measurement of miles physically stored in the battery. H

EV & Vehicle Terminology

H

HEV, or hybrid electric vehicle

A hybrid electric vehicle, or HEV, combines an internal combustion engine with an electric motor and battery but does not recharge its traction battery from an external electricity supply. Energy is recovered through the vehicle's own operation, including regenerative braking. A full HEV can use the engine, electric motor or both to propel the vehicle depending on operating conditions. This differs from a mild hybrid, where the electrical system assists the engine but does not independently provide normal propulsion. HEVs do not require public or home EV charging infrastructure because there is no plug-in traction-battery connection.

EV & Vehicle Terminology

High-Level Communication

Also called: HLC High-Level Communication, or HLC, is digital communication between an EV and EVSE used in addition to the basic charging signalling defined for the charging interface. ISO 15118 uses HLC to exchange the richer information needed for functions such as Plug & Charge and managed charging. For wired ISO 15118-3 communication, the EV and EVSE establish the data link over the charging connection using power-line communication. ISO 15118 also defines other physical-layer options in later parts of the standards family. HLC is separate from OCPP. HLC carries vehicle-to-EVSE communication, while OCPP normally connects the charging station to its CSMS.

Protocols & Communications

Home charging point

A home charging point is EV charging equipment installed for private residential use, normally to provide controlled AC charging from the property's electrical supply. It can be installed indoors or outdoors where the equipment and location are suitable. In Great Britain, private charge points sold for domestic use are covered by the Electric Vehicles (Smart Charge Points) Regulations 2021 unless an exemption applies. The regulations require smart functions and other device-level features. The charging power available at home depends on the electrical installation, supply capacity, EVSE rating and the vehicle's onboard charger.

Charging & Electrical Engineering

HomePlug Green PHY

HomePlug Green PHY is a power-line communications technology used in wired EV charging to carry high-level data between the vehicle and EVSE. It is the PLC technology associated with CCS implementations of ISO 15118. The communication is coupled onto the charging conductors rather than requiring a separate Ethernet cable between the vehicle and charge point. ISO 15118-3 defines the physical and data-link requirements for this wired communication. HomePlug Green PHY sits below the ISO 15118 application layer. It transports the data; it does not define Plug & Charge, charging tariffs or the charging-control messages themselves.

Protocols & Communications

Hydrogen

Hydrogen is an energy carrier that can be stored and used in a fuel cell to generate electricity. Fuel-cell electric vehicles commonly carry compressed hydrogen onboard and convert it into electrical power while driving. Hydrogen is not itself a primary renewable energy source. Its lifecycle emissions depend on how it is produced, processed, transported and dispensed. This distinction matters when comparing tailpipe emissions with full energy-system emissions. An FCEV can have zero tailpipe CO2 while the hydrogen supply chain still has associated emissions. I

Battery & Energy Storage

I

ICE

Also called: internal combustion engine ICE means internal combustion engine, the petrol or diesel engine used to propel conventional vehicles and many hybrid vehicles. The engine converts energy released by fuel combustion into mechanical power. BEVs do not use an internal combustion engine for propulsion. PHEVs, HEVs and MHEVs combine an ICE with different forms of electric assistance. In EV charging discussions, ICE also appears in terms such as "ICEing", which describes a combustion-engine vehicle blocking an EV charging bay.

EV & Vehicle Terminology

ICE blocked

Also called: ICE'd, ICE blocked ICE blocked describes an EV charging bay that cannot be used because a vehicle with an internal combustion engine is occupying the charging space. It is a practical access failure even when the charger itself is working. Operators may manage the problem through bay design, signage, parking controls or enforcement. Hardware uptime does not necessarily capture bay obstruction, which is why physical site access also matters to the charging experience.

Operations & Infrastructure

ICEing

ICEing is when a vehicle with an internal combustion engine occupies a bay intended for EV charging and prevents an EV from using it. The name comes from the abbreviation ICE. The charging equipment may remain technically available while the bay is unusable, so the problem sits outside a simple charger-fault metric. Site operators can reduce ICEing through clear bay marking, parking controls and physical layout.

Operations & Infrastructure

IEC 61851

IEC 61851 is an international standards family covering conductive electric vehicle charging systems. IEC 61851-1 sets general requirements for EV supply equipment, including operating conditions, the EV-to-EVSE connection and electrical safety. Other parts of the family address specific charging equipment and use cases. That includes DC charging equipment and, from 2026, a dedicated part for Megawatt Charging System EVSE. IEC 61851 works alongside connector standards such as IEC 62196 and vehicle-to-EVSE communication standards such as ISO 15118.

Standards, Safety & Compliance

IEC 62196

IEC 62196 is the international standards family covering EV plugs, socket-outlets, vehicle connectors and vehicle inlets for conductive charging. It defines the physical interface requirements used by several common EV charging connector configurations. IEC 62196-2 covers AC pin and contact-tube accessories. The current edition, IEC 62196-2:2025, includes the standardised AC configurations used for interfaces such as Type 2. IEC 62196 defines the connection hardware rather than the complete charging system. Charging behaviour and electrical requirements are covered through standards such as IEC 61851, with higher-level communication covered separately.

Standards, Safety & Compliance

IEC 63110

IEC 63110 is a standards family for the management of electric vehicle charging and discharging infrastructure. IEC 63110-1:2022 defines the architecture, use cases and basic concepts for communication between e-mobility actors and the electricity system. Its scope includes energy-transfer management, EVSE asset management, authentication and payment, roaming, metering information and cybersecurity. IEC 63110 addresses an infrastructure-management layer. It should not be confused with ISO 15118, which focuses on vehicle-to-EVSE communication, or with a particular proprietary back-office implementation.

Protocols & Communications

IEC 63119

IEC 63119 is an international standards family for information exchange used in EV charging roaming services. It describes interaction between charging service providers, charging station operators and clearing-house platforms through roaming endpoints. IEC 63119-1:2025 is the current general part and replaced the 2019 edition. The 2025 revision expands roaming roles, adds CDR terminology and updates the security stack to TLS 1.3. IEC 63119 does not define vehicle-to-charge-point communication or the station-to-operator interface. Those functions sit elsewhere in the charging architecture.

Standards, Safety & Compliance

IEC TS 63379

IEC TS 63379:2026 specifies the vehicle connector, vehicle inlet and cable assembly used for megawatt DC charging. It is the IEC technical specification for the coupler hardware associated with the Megawatt Charging System. The specification applies up to 1,500 V DC and currents up to and including 3,000 A, with thermal sensing or thermal transport and sensing as part of the system architecture. IEC TS 63379 covers the connection hardware. Requirements for MCS DC EV supply equipment are set out separately in IEC 61851-23-3:2026.

Standards, Safety & Compliance

Import limitation

Import limitation controls electrical demand so a site does not draw more power from the distribution network than its agreed limit permits. In EV charging, this can involve reducing charger power when the rest of the site's demand rises. Import limitation is particularly useful where the theoretical combined demand of the chargers and other equipment is higher than the capacity that can be imported at the connection point. The control system prevents that worst-case total from occurring in practice. Under G100, import limitation can form part of a Customer Limitation Scheme where the DNO has agreed that current at the connection point must be restricted.

Grid & Energy Management

Inverter

An inverter is power electronics that converts direct current into alternating current. In an electric vehicle, the traction inverter takes DC energy from the battery and supplies controlled AC to the electric motor. The term is sometimes used loosely for other power-conversion equipment, which causes confusion in EV charging. Converting incoming AC electricity into DC for a battery is an AC-to-DC conversion function performed by the onboard charger or by the power electronics inside a DC charge point. Bidirectional power converters can transfer energy in both directions, so their hardware may combine functions that older terminology treated separately.

Charging & Electrical Engineering

ISO 15118

Also called: Vehicle-to-grid communication interface, V2G communication interface ISO 15118 is a family of international standards for digital communication between an electric vehicle and EV charging equipment. It defines higher-level communication used for functions including charging control, identification and Plug & Charge. ISO 15118-2 is widely associated with first-generation Plug & Charge implementations. ISO 15118-20 defines second-generation network and application-layer requirements and includes message sequences for bidirectional power transfer. The standard sits on the vehicle-to-EVSE side of the system. Back-office communication between the charging station and a CSMS is normally handled separately through OCPP. J K

Protocols & Communications

K

kW

Also called: kilowatt A kilowatt, or kW, is a unit of power equal to 1,000 watts. In EV charging it describes the rate at which electrical energy is being transferred, or the maximum rate equipment is designed to deliver or accept. A 7 kW charge point and a 150 kW charge point differ in power, not energy capacity. How much energy reaches the vehicle depends on how long that power is maintained. kW should not be confused with kWh. Power is a rate; kWh measures energy.

Charging & Electrical Engineering

kWh

Also called: kilowatt-hour, kW h A kilowatt-hour, or kWh, is a unit of energy equal to using or delivering one kilowatt of power for one hour. EV battery capacity and charging-session energy are commonly stated in kWh. A charger delivering a constant 50 kW for 30 minutes transfers 25 kWh of energy, ignoring losses. The same 25 kWh could be delivered more slowly at lower power over a longer period. Electricity tariffs are usually expressed as a price per kWh, while the charger or connection rating is stated in kW. L

Charging & Electrical Engineering

L

Lead-acid battery

A lead-acid battery is a rechargeable battery chemistry using lead-based electrodes and a sulphuric-acid electrolyte. It is one of the oldest rechargeable battery technologies still used at large scale. In vehicles, lead-acid batteries are commonly associated with low-voltage auxiliary systems such as the 12 V supply. They are not the normal traction-battery chemistry in modern passenger BEVs. Some EVs now use other chemistries for their auxiliary battery, so "12 V battery" and "lead-acid battery" should not be treated as exact synonyms.

Battery & Energy Storage

Lithium-ion battery

Also called: Li-ion battery A lithium-ion battery stores and releases electrical energy through reversible electrochemical reactions involving lithium ions. During charging and discharging, lithium ions move through the electrolyte while electrons travel through the external electrical circuit. Lithium-ion describes a family of battery chemistries rather than one cell recipe. EV batteries can use different cathode, anode and electrolyte materials, which changes energy density, cost, charging behaviour and thermal characteristics. Lithium-ion batteries dominate current battery-electric vehicle production because they can combine high energy storage with rechargeable cycle life and high power output.

Battery & Energy Storage

Load balancing

Also called: EV load balancing, charger load balancing, load management EV charging load balancing controls how available electrical capacity is shared between charge points so a site stays within its electrical limits. Instead of allowing every charger to draw its maximum power at the same time, the control system adjusts charging power as site demand changes. Load balancing can use a fixed site limit or respond dynamically to measurements from the incoming supply and other electrical loads. That matters on sites where EV charging shares capacity with buildings, plant, lighting or other equipment. The aim is to use more of the capacity already available without exceeding the site's agreed or safe operating limits. Depending on the installation, the system may also prioritise particular chargers or groups of chargers.

Grid & Energy Management

Ludicrous mode

Ludicrous Mode is a historic Tesla performance-mode name associated with maximum acceleration on earlier high-performance Model S and Model X vehicles. Tesla's current performance terminology has changed on newer vehicles. Current Model S documentation uses drive modes such as Insane and Drag Strip Mode on relevant configurations rather than presenting Ludicrous as a universal current feature. The term remains in the glossary because it is established Tesla and EV culture terminology. M

EV & Vehicle Terminology

M

Maximum demand

Maximum demand is the highest electrical load a site places on its supply over a defined period. For EV charging design, it is used to assess whether the existing electrical installation and grid connection can support the proposed charging load. Simply adding together the nameplate rating of every charger can overstate what the site will actually draw, because vehicles do not always charge simultaneously or at maximum power. Existing building demand must also be considered. Load balancing can control EV demand so the site's actual maximum stays within an acceptable limit, allowing more charge points to share the available capacity.

Grid & Energy Management

Megawatt Charging System

Also called: MCS The Megawatt Charging System, or MCS, is a high-power DC charging system developed for heavy-duty electric vehicles using the MCS coupler. It is aimed at vehicles that need much higher charging power than conventional passenger-car charging systems. IEC TS 63379:2026 specifies the MCS vehicle connector, vehicle inlet and cable assembly. IEC 61851-23-3:2026 covers the associated DC EV supply equipment. MCS charging also uses digital communication between the EV and EVSE. IEC 61851-23-3 points to ISO 15118-10 and ISO 15118-20 for communication used to control energy transfer.

Connectors & Charging Modes

MHEV, or mild hybrid

A mild hybrid electric vehicle, or MHEV, uses a small electric motor and battery to assist a petrol or diesel engine but cannot be charged from an external EV charge point. The engine remains the mechanical source that drives the vehicle. Mild-hybrid systems can recover energy during braking and use the motor-generator to assist the engine, restart it or support electrical loads. Many current systems use a 48 V electrical architecture, although MHEV design is not defined by one voltage alone. An MHEV has no plug-in charging requirement. That separates it from a PHEV, which has a larger externally rechargeable traction battery.

EV & Vehicle Terminology

MID meter

A MID meter is an energy meter placed on the EU market under the Measuring Instruments Directive framework for regulated measurement tasks. The MID sets essential requirements and conformity-assessment routes for covered measuring instruments. Directive (EU) 2026/706 amended the MID to add harmonised measurement rules for electric vehicle charging and hydrogen refuelling stations. That change means charger metrology should be assessed against the current amended legislation rather than older guidance alone. A MID-compliant meter is one part of a charging-billing system. National legal-metrology rules can add requirements for how measurement data is displayed, secured or verified.

Standards, Safety & Compliance

Miles per kWh

Also called: mi/kWh, m/kWh Miles per kWh measures EV energy efficiency by showing how far the vehicle travels for each kilowatt-hour of electrical energy used. A higher number means the vehicle is travelling further for the same amount of energy. The figure changes with speed, temperature, terrain, tyres, payload and use of heating or air conditioning. Miles per kWh can be combined with usable battery capacity to estimate range, although real-world results will still vary.

EV & Vehicle Terminology

Modbus

Modbus is an application-layer messaging protocol used for client/server communication between industrial devices. It is widely used with meters, inverters, battery systems and site controllers because the data model is simple and well established. Modbus can run over serial links or TCP/IP. In an EV charging site, a power controller might use Modbus to read a meter or coordinate with a BESS while using OCPP separately for charger-to-CSMS communication. Modbus does not define what an EV charger should do with a site measurement. The register map, control logic and integration behaviour still need to be specified by the equipment manufacturer or system integrator.

Protocols & Communications

Mode 2 charging

Mode 2 charging connects an EV to an AC supply through a standard socket-outlet using a cable that includes control and protective functions. IEC 61851 defines Mode 2 with a control-pilot function and protection against electric shock between the vehicle and the supply plug. In UK domestic use, Mode 2 is the basis of the portable charging lead often called a granny charger. IET guidance says single-phase charging from a BS 1363 socket usually operates at 10 A or less. Mode 2 should not be treated as permission to use any socket for long-duration charging. The socket, wiring and protective arrangements still need to be suitable for EV charging.

Connectors & Charging Modes

Mode 3 charging

Mode 3 charging uses dedicated AC EV supply equipment in which the control-pilot function extends into equipment permanently connected to the AC supply. It is the normal charging mode for dedicated AC wallboxes and many public AC charge points. Mode 3 charging can use tethered cables or socketed equipment. In Europe, Type 2 is the common vehicle interface associated with this charging mode. The vehicle's onboard charger converts the incoming AC power to DC for the battery. The EVSE controls the safe supply and communicates the available current to the vehicle.

Connectors & Charging Modes

Mode 4 charging

Mode 4 charging uses an off-board charger to supply controlled DC power to the electric vehicle. The control-pilot function extends to equipment permanently connected to the AC supply, while the main AC-to-DC conversion takes place outside the vehicle. This is the IEC 61851 charging mode used for DC rapid and ultra-rapid charging. The vehicle communicates its allowable charging conditions and the EVSE adjusts output within those limits. CCS and CHAdeMO are examples of connector and communication systems used for Mode 4 charging. Mode 4 describes the charging arrangement rather than one particular connector.

Connectors & Charging Modes

Motability

The Motability Scheme lets eligible disabled people exchange a qualifying mobility allowance for a vehicle lease, including electric cars. The lease package normally includes insurance, servicing and breakdown support. For a first fully electric car on the Scheme, Motability currently offers a 7 kW home chargepoint and standard installation where the property is suitable, subject to its current eligibility conditions. Motability is a UK mobility scheme rather than an EV technology term. It remains in the glossary because charging arrangements can affect the practical choice of an electric Motability vehicle.

EV & Vehicle Terminology

MPG

Also called: miles per gallon MPG means miles per gallon, a fuel-economy measure showing how far a vehicle travels for each gallon of liquid fuel. It is used for petrol, diesel and some hybrid-vehicle comparisons. Battery-electric vehicle efficiency is normally expressed in units such as miles per kWh or kWh per 100 km rather than MPG. Plug-in hybrids can have published fuel-economy figures that depend heavily on how much of the test cycle is completed using externally charged electricity. N

EV & Vehicle Terminology

N

National Access Point

Also called: NAP A National Access Point, or NAP, is a mechanism set up by an EU Member State to make transport-related data discoverable and accessible for exchange and reuse. A NAP can take forms such as a portal, database, repository or data marketplace. AFIR and its implementing data rules bring public charging-infrastructure data into this wider European mobility-data framework. OCPI 2.3.0 added support for data needed for AFIR and NAP use cases. A NAP is not a charging backend or roaming platform. It is part of the public data-access architecture around transport information.

Standards, Safety & Compliance

NiCad

Also called: nickel-cadmium, Ni-Cd NiCad is a rechargeable nickel-cadmium battery chemistry using nickel and cadmium-based electrodes. It offers good power capability and long cycle life but uses toxic cadmium. Nickel-cadmium technology appeared in earlier electric and industrial applications but is not a mainstream traction-battery chemistry in current passenger EVs. Modern road EVs predominantly use lithium-ion battery families, while some earlier hybrid vehicles used nickel-metal hydride rather than nickel-cadmium.

Battery & Energy Storage

NOx

NOx means nitrogen oxides, principally nitric oxide and nitrogen dioxide in road-vehicle exhaust and air-quality regulation. They form during high-temperature combustion and contribute to air pollution. NOx is not another name for nitrous oxide, N2O. Nitrous oxide is a different compound and a greenhouse gas. Battery electric vehicles have no tailpipe NOx emissions because they have no combustion exhaust. NOx can still arise elsewhere in the wider energy and industrial lifecycle. O

EV & Vehicle Terminology

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OCPI

Also called: Open Charge Point Interface OCPI, the Open Charge Point Interface, is an open protocol for exchanging EV charging data between Charge Point Operators, e-mobility service providers and roaming platforms. It supports information such as locations, availability, tariffs, authorisation, sessions and Charging Detail Records. OCPI solves a different interface problem from OCPP. OCPP usually connects charging equipment to its management system. OCPI connects the organisations and platforms that need to exchange charging and roaming information. The current OCPI version is 2.3.0. It adds support for data required by EU National Access Points under AFIR, along with direct-payment functions, Plug & Charge indication and extensibility.

Payments, Roaming & Authentication

OCPP

Also called: Open Charge Point Protocol OCPP, the Open Charge Point Protocol, is an open communication protocol between an EV charging station and a Charging Station Management System, or CSMS. It carries operational messages such as authorisation, transaction data, meter values, status changes and remote commands. OCPP 1.6 remains widely deployed. OCPP 2.0.1 added a richer device model, stronger security capabilities and improved transaction handling. OCPP 2.1, released in 2025, adds support for ISO 15118-20, bidirectional charging and Distributed Energy Resource control. OCPP does not define the communication between the vehicle and the charge point. That is handled by standards such as IEC 61851 and ISO 15118.

Protocols & Communications

OLEV

OLEV was the Office for Low Emission Vehicles, the former name of the UK government unit now called the Office for Zero Emission Vehicles, or OZEV. The organisation was renamed in 2020. Older grant guidance, installer documents and EV articles can still refer to OLEV. Current UK chargepoint and zero-emission vehicle grant information is published under OZEV. This glossary page is retained because the old acronym still appears in searches and historic documentation.

Standards, Safety & Compliance

OLEV grant

OLEV grant is a historic label used for UK government electric-vehicle and chargepoint support administered when OZEV was still called the Office for Low Emission Vehicles. There was no single permanent grant with one set of rules under that name. Home, workplace and vehicle grant schemes have changed several times since the OLEV period. Current chargepoint grants are published by OZEV and several existing schemes run only until 31 March 2027. Treat "OLEV grant" as legacy terminology and check the current GOV.UK scheme before quoting eligibility or grant values.

Standards, Safety & Compliance

Onboard charger

Also called: OBC, on-board charger An onboard charger is the power-conversion equipment inside an EV that converts incoming AC charging power into controlled DC for the traction battery. Its rating places an upper limit on the AC power the vehicle can accept. A car with an 11 kW onboard charger will not take 22 kW from a 22 kW AC charge point simply because that power is available. The vehicle will remain limited by its own charger and any lower supply or EVSE limit. During DC charging, the main AC-to-DC conversion happens in the external charger, so the vehicle's onboard AC charger is bypassed for that conversion stage.

Charging & Electrical Engineering

OPDD

Also called: Open PEN Detection Device An Open PEN Detection Device, or OPDD, detects conditions associated with an open PEN conductor fault and disconnects the EV from the charging equipment. It is used in UK EV charging applications where the selected installation design relies on this type of protection. IET 01:2024 provides the specification for OPDD behaviour in household and similar EV charging applications. The IET states that OPDDs are intended to deal with faults on distribution-network conductors outside the customer's installation. An OPDD should not be treated as a general-purpose answer to every earthing risk. The installation still has to meet the applicable requirements of BS 7671 and the manufacturer's instructions.

Standards, Safety & Compliance

Open PEN fault

Also called: broken PEN conductor, open PEN conductor An open PEN fault is a break or loss of continuity in the combined protective earth and neutral conductor used on a TN-C-S distribution network. In this condition, conductive parts connected to the installation's protective conductors can rise to a dangerous voltage relative to the ground. The risk is important for EV charging because a person can be standing on the ground while touching the vehicle body. UK charging-installation requirements therefore include protective measures for situations where a PME earthing facility is used. An Open PEN Detection Device is one recognised way of detecting symptoms of this distribution-network fault and disconnecting the vehicle in accordance with its specification.

Standards, Safety & Compliance

OpenADR

OpenADR is an open standard for automated demand-response signalling between energy providers, aggregators and flexible energy resources. It carries events, prices and related information used to change electricity consumption or generation in response to grid or market conditions. EV charging can participate in OpenADR programmes directly or through an energy-management gateway. The OpenADR Alliance publishes programme models that include residential EV charging, public charging and distributed-energy-resource demand response. OpenADR and OCPP address different interfaces. OpenADR carries demand-response information; OCPP manages charging stations and can apply charging limits or schedules in response.

Protocols & Communications

OTA update

Also called: over-the-air update, remote firmware update An OTA update installs new software or firmware on a connected charge point remotely over a communications network. It allows a charger fleet to receive fixes or new software without an engineer visiting every site. Remote delivery creates security and operational requirements of its own. The device should be able to verify that an update comes from an authorised source and has not been altered before installation. OCPP includes firmware-management functions. Current OCPP security guidance also covers secure firmware updates as part of the charging-station security model. P

Cybersecurity & Firmware

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PAS 1899

PAS 1899:2022 is the British specification for making public EV charge points and their surrounding charging environment accessible to a wider range of users. It was published by BSI in October 2022 and remains current. The specification covers matters such as the physical environment, charge-point placement and information provision. It applies to different public charging arrangements, including tethered and socketed equipment. PAS 1899 is focused on accessibility. It is intended to be used alongside the other standards and regulations that govern electrical installation, equipment safety and public charging.

Standards, Safety & Compliance

PAYG

Also called: pay as you go charging PAYG means pay as you go, where a driver pays for charging as it is used rather than through a recurring charging subscription. The payment method can be contactless, app-based or another operator-supported route. PAYG is everyday language rather than the main regulatory term. UK and EU public-charging rules use concepts such as ad hoc access and ad hoc payment for charging without a pre-existing contract. A PAYG price can differ from a subscription or membership tariff on the same network.

Payments, Roaming & Authentication

Payment roaming

Also called: EV roaming, e-roaming, charging roaming EV charging payment roaming lets a driver use one app, RFID card or charging contract across charge point networks operated by different companies. The organisations involved exchange authorisation, session and billing data so the driver does not need a separate account for every network. Roaming can be arranged through a direct agreement between parties or through an external roaming provider or hub. Protocols such as OCPI are commonly used to exchange the data needed between CPOs and eMSPs. Under the UK Public Charge Point Regulations 2023, CPOs must make their paid public charge points available through at least one third-party roaming provider. That requirement took effect on 24 November 2025.

Payments, Roaming & Authentication

Peak shaving

Peak shaving reduces a site's highest electrical demand by controlling loads, using stored energy or combining both approaches. The aim is to keep short periods of high demand below a target level. On an EV charging site, chargers can be throttled when building demand is high, or a BESS can supply part of the load so less power is drawn from the grid. Peak shaving can reduce exposure to capacity constraints or demand-related charges where those apply. Its value depends on the site's load profile, tariff and available control assets.

Grid & Energy Management

PEM fuel cell

Also called: proton-exchange membrane fuel cell, polymer electrolyte membrane fuel cell A PEM fuel cell uses a proton-conducting polymer membrane as its electrolyte. Hydrogen is supplied to the anode and oxygen from air to the cathode, producing electricity, heat and water through the electrochemical reaction. PEM fuel cells operate at relatively low temperatures compared with several other fuel-cell types and can respond quickly to changing load. Those characteristics make PEM systems the main fuel-cell technology used in hydrogen road vehicles.

Battery & Energy Storage

Phase balancing

Phase balancing distributes electrical load across the phases of a three-phase supply so one phase is not overloaded while spare capacity remains on the others. It is especially relevant where several single-phase EV chargers share a three-phase site supply. A site can be within its overall power limit and still have a problem on one phase. The current in each phase therefore needs to be considered when allocating charging power, rather than treating total site kW as the only constraint. Phase balancing can be designed statically by spreading chargers across phases, or managed dynamically where compatible hardware and control architecture allow charging demand to be adjusted.

Grid & Energy Management

PHEV

Also called: plug-in hybrid electric vehicle, plug-in hybrid A plug-in hybrid electric vehicle, or PHEV, combines an electric motor and externally rechargeable battery with an internal combustion engine. The battery can be charged by connecting the vehicle to an external electricity supply. A PHEV can drive using electricity for part of a journey and use its engine when required. The exact control strategy and electric-only range vary by vehicle. The charging port is the practical distinction from a conventional HEV or MHEV, which cannot normally recharge the traction battery from the mains.

EV & Vehicle Terminology

Plug & Charge

Also called: Plug and Charge, PnC Plug & Charge is an ISO 15118 feature that allows a compatible EV to authenticate for charging automatically after it is connected. The vehicle presents a digital contract certificate, which is checked through the Plug & Charge trust infrastructure before the session is authorised. The driver does not need to present an RFID card or open an app at the charge point. Contract identification and authorisation are handled through the vehicle-to-charge-point communication and the supporting backend systems. Plug & Charge relies on Public Key Infrastructure to establish trust between participating vehicles, charging services and certificate authorities. ISO 15118-2 supports the first generation of Plug & Charge, while ISO 15118-20 supports the second generation.

Payments, Roaming & Authentication

Plug-in Car Grant

Also called: PICG The Plug-in Car Grant was a UK government subsidy that reduced the purchase price of eligible plug-in cars. The grant stopped being available for ordinary new-car orders on 14 June 2022, with a limited exception for wheelchair-accessible vehicles. The UK introduced a new Electric Car Grant in July 2025 under different rules, so PICG should not be treated as the current car-grant scheme. Older vehicle listings and finance documents may still mention PICG because the grant formed part of the purchase price when those cars were new.

Standards, Safety & Compliance

Power Line Communication

Also called: PLC Power Line Communication, or PLC, carries digital data over conductors that also have an electrical power function. In wired ISO 15118 charging, PLC provides the data link used for high-level communication between the EV and EVSE. ISO 15118-3 defines physical and data-link requirements for wired high-level communication in addition to the basic charging signalling. CCS implementations commonly use HomePlug Green PHY technology for this PLC link. PLC is the communication medium at the charging interface. The ISO 15118 application messages carried over it are a separate layer of the system.

Protocols & Communications

Powerwall

Tesla Powerwall is a home battery storage product that stores electrical energy from solar generation or the grid for later household use. It is a stationary battery product rather than an EV traction battery. Powerwall can be combined with home solar and backup-power functions depending on the installation. Tesla's current Powerwall 3 includes an integrated solar inverter. The term is a Tesla product name, so it should not be used as the generic name for all residential battery-energy-storage systems.

Battery & Energy Storage

Preheat

EV preheating warms the cabin, battery or both before the vehicle starts its journey. Many EVs allow this to be scheduled or started remotely. When the vehicle is plugged in, cabin conditioning can use external electricity rather than drawing all of the energy from the traction battery after departure. Battery preconditioning is a more specific term for controlling battery temperature to improve charging or driving performance.

EV & Vehicle Terminology

ProPILOT

Nissan ProPILOT is a driver-assistance system combining functions such as speed and distance control with steering assistance on supported vehicles. Exact capabilities vary by model and market. Nissan's current ARIYA documentation describes ProPILOT Assist as using Intelligent Cruise Control and Steering Assist functions. ProPILOT assists the driver rather than replacing the driver's responsibility for the vehicle. Q

EV & Vehicle Terminology

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Quadricycle

A quadricycle is a four-wheel L-category vehicle that meets the classification criteria for a light L6e or heavy L7e vehicle rather than a full passenger-car category. Electric quadricycles use an electric motor within the applicable power and mass limits. UK MOT guidance defines light and heavy quadricycles separately and applies different limits to each category. An electric quadricycle can look car-like while being regulated under a different vehicle category from an M1 passenger car. R

EV & Vehicle Terminology

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Range

EV range is the distance a vehicle can travel before it needs additional energy. Published range can come from a standardised test such as WLTP, while the vehicle display estimates remaining range from current operating information. Real-world range changes with speed, weather, heating or cooling, terrain, payload and driving style. Battery capacity matters, but efficiency is equally important. Two vehicles with the same usable kWh can have different range.

EV & Vehicle Terminology

Range anxiety

Range anxiety is concern that an EV may not have enough remaining energy or accessible charging to complete the intended journey. It can relate to vehicle range, charger availability or uncertainty about the route. Larger batteries, more reliable public charging and better route planning have reduced the problem for many journeys, but it can still matter where charging coverage or reliability is poor. Range anxiety is a user-behaviour term rather than a technical battery condition.

EV & Vehicle Terminology

Range per hour

Also called: RpH, miles added per hour Range per hour estimates how much driving distance a vehicle gains for each hour spent charging. It combines charging power with the vehicle's energy efficiency. A 7 kW charge point does not add the same number of miles per hour to every vehicle because larger or less efficient vehicles use more kWh per mile. RpH is useful for drivers but less precise than quoting charging power and energy because it depends on vehicle efficiency and conditions.

Charging & Electrical Engineering

Range-extended electric vehicle

Also called: REEV, REX, range extender A range-extended electric vehicle is driven by an electric motor but carries a small internal combustion engine that can generate electricity when additional range is needed. The engine acts as an onboard generator rather than the normal mechanical drive source. UK vehicle definitions treat a range-extended electric vehicle as a special case of plug-in hybrid. The battery can be charged from an external electricity supply as well as from the onboard generator. The distinction from many PHEVs is drivetrain layout: a REEV is intended to drive electrically while the combustion engine supplies electrical energy rather than routinely driving the wheels.

EV & Vehicle Terminology

Rapid charging

Rapid charging is the UK Department for Transport's current label for public EV charging rated from 50 kW to under 150 kW. Charging rated at 150 kW and above is labelled ultra-rapid in the same statistical series. These labels describe power bands used in UK public-charging statistics. Other parts of the EV charging industry may use different labels, so the kW rating is more precise when comparing hardware. Rapid charging is normally DC charging. The charge point performs the main AC-to-DC conversion and the vehicle controls how much DC power its battery can accept at each point in the charging session.

Charging & Electrical Engineering

RCD

Also called: Residual Current Device A Residual Current Device, or RCD, detects an imbalance caused by current flowing outside the intended circuit and disconnects the supply when its operating threshold is reached. RCD protection is an important part of electric-shock protection in EV charging installations. Section 722 of BS 7671 contains specific RCD requirements for charging points. EVSE can also produce DC residual current, which affects the type of RCD and additional DC detection that may be required. The correct arrangement depends on the EVSE, the installation and upstream protection. Installer decisions should therefore follow the current BS 7671 requirements and the charging-equipment manufacturer's instructions.

Standards, Safety & Compliance

RDC-DD

Also called: Residual Direct Current Detecting Device A Residual Direct Current Detecting Device, or RDC-DD, detects DC residual current in Mode 3 EV charging equipment so the protective system can respond appropriately. It is used because DC residual current can affect the operation of some upstream RCD types. BS IEC 62955 covers RDC-DDs for Mode 3 charging. An RDC-DD detects the DC residual current but does not itself provide the complete mechanical switching function; that switching is provided by another device. Where suitable DC residual-current protection is provided in the EVSE, BS 7671 allows different RCD arrangements from those required where that protection is absent. The final selection still depends on the current standard and the equipment design.

Standards, Safety & Compliance

Regenerative braking

Regenerative braking slows an electrified vehicle by using the traction motor as a generator and returning some of the vehicle's kinetic energy to the battery. Friction brakes are still required for stronger braking, low-speed operation and conditions where regeneration is limited. The amount of recoverable energy depends on vehicle speed, battery condition, traction limits and the manufacturer's control strategy. Regeneration improves efficiency because some energy that would otherwise become heat in the brakes is reused.

EV & Vehicle Terminology

Remote diagnostics

Remote diagnostics lets an operator inspect charger status, faults and diagnostic information through a management system without first visiting the site. It can help support teams decide whether a problem can be resolved remotely or needs an engineer. OCPP supports remote monitoring and device-management functions, with later protocol versions providing a richer device model for charger components and variables. Diagnostic logs can also be collected as part of charger support. Remote diagnostics is useful only when the data is trustworthy. Incomplete telemetry or inconsistent firmware versions can make a remote fault look different from the condition at the charger.

Operations & Infrastructure

Residual Charge

The remaining capacity of a battery compared to its capacity when new. Usually expressed as a percentage

Charging & Electrical Engineering

Residual value

Residual value is the expected or actual value remaining in a vehicle after a defined period of ownership, lease or finance. It is the value used when estimating how much of the original purchase price has been lost. Leasing and finance models can use a forecast residual value when setting payments. The eventual used-market value can differ because vehicle condition and market demand change. For EVs, battery health, charging capability and remaining warranty can influence residual value alongside the same age, mileage and condition factors that affect other vehicles.

EV & Vehicle Terminology

RFID card

An RFID card or token identifies a charging customer or account when it is presented to a compatible charge point reader. The identifier is sent through the charging platform so the session can be authorised and attributed to the correct account. RFID remains common on public, fleet and workplace networks because it can work without the driver opening a phone app at the charger. A roaming-enabled RFID credential can also authorise charging on networks operated by other CPOs where the relevant commercial and technical agreements exist.

Payments, Roaming & Authentication

RFL

Also called: Road Fund Licence RFL means Road Fund Licence, an outdated informal name sometimes used for UK Vehicle Excise Duty. The current statutory term is Vehicle Excise Duty, commonly called vehicle tax. There is no current UK "road fund" into which the charge is directly paid. Using VED avoids confusion when discussing current tax rules. Electric vehicles have been liable for VED since 1 April 2025, so older claims that EVs are exempt from road tax are no longer current. S

Standards, Safety & Compliance

S

SAE J1772

SAE J1772 is the North American standard covering conductive charging requirements for electric and plug-in hybrid vehicles. It defines the charging method along with functional, electrical and dimensional requirements for the vehicle inlet and mating connector. The current revision is SAE J1772_202401. The standard is closely associated with the Type 1 AC connector used across the North American installed base. SAE J1772 and SAE J3400 are separate standards. J3400 standardises the interface commonly known as NACS, while J1772 remains relevant to existing vehicles, EVSE and adapter strategies.

Connectors & Charging Modes

SAE J3400 / NACS

Also called: North American Charging System, NACS, J3400 SAE J3400 is the North American recommended practice that standardises the charging interface commonly known as the North American Charging System, or NACS. It covers physical and electrical requirements for a hand-mated coupler that can transfer either DC power or single-phase AC power. SAE issued the first J3400 version in December 2023 and revised it in September 2024. The standard gives the previously proprietary connector a published industry specification for wider vehicle and charging-equipment adoption. J3400 describes more than the shape of the plug. Charger manufacturers also need to account for the electrical, communication and safety requirements that apply to the complete charging implementation.

Connectors & Charging Modes

SECC

Also called: Supply Equipment Communication Controller A Supply Equipment Communication Controller, or SECC, is the communication controller on the EVSE side of the ISO 15118 interface. It exchanges high-level messages with the Electric Vehicle Communication Controller in the vehicle. The SECC participates in establishing the communication session and handles ISO 15118 messages used for charging control, authorisation and other supported services. A charge point controller can host SECC functionality as part of a wider EVSE control design. The SECC role itself is defined by the vehicle-to-EVSE communication architecture, not by the physical form of the controller board.

Protocols & Communications

Second-use battery

A second-use EV battery is a traction battery repurposed for another duty after it no longer meets the requirements of its original vehicle. A common destination is stationary energy storage. The battery needs assessment before reuse because packs age differently and their remaining capacity, power capability and safety condition vary. Second use extends product life before recycling, but it is not automatically the best route for every pack. Technical condition and economics determine whether reuse, remanufacturing or recycling is appropriate.

Battery & Energy Storage

Secure boot

Secure boot is a startup security process that checks software before allowing it to run on the device. Its purpose is to stop unauthorised or altered code from being accepted as trusted charger software. The exact implementation depends on the processor and product architecture. A charger may use cryptographic verification anchored in hardware or another protected root of trust. Secure boot protects the startup path. It complements signed firmware and secure update controls, which deal with how new code reaches the device in the first place.

Cybersecurity & Firmware

Self-charging hybrid

Self-charging hybrid is a marketing term for a hybrid electric vehicle that cannot be plugged into an external electricity supply. Its traction battery is charged through the vehicle's operation, including regenerative braking and engine-generated power. The phrase can be misleading if read literally because the energy still comes from fuel and recovered vehicle motion. The technically clearer term is HEV, or hybrid electric vehicle.

EV & Vehicle Terminology

Signed firmware

Signed firmware is firmware accompanied by a cryptographic signature that lets a charger verify who authorised the software and whether it has been altered. The device checks that signature before accepting or installing the update. Digital signing helps prevent a corrupted or unauthorised firmware image from being treated as legitimate software. It is one part of a secure software-update process rather than a complete security system on its own. OCPP security guidance includes secure firmware-update mechanisms that use signing certificates to verify firmware integrity.

Cybersecurity & Firmware

Slow charging

Slow charging is a legacy UK label for lower-power EV charging. It was commonly used for domestic and other low-power AC charging. From 2026, UK Department for Transport statistics use Standard for charging rated 3 kW to under 8 kW and Standard Plus for 8 kW to under 50 kW. The older term remains useful when interpreting historic articles, but current technical content should state the actual kW rating.

Charging & Electrical Engineering

Smart charging

Smart charging changes the timing or rate of EV charging in response to communication signals or operating constraints. It can delay charging, reduce power or schedule charging for periods that better suit the electricity system, tariff or site. UK government guidance defines smart charging around the ability to delay or modulate charging in response to an external signal. More advanced arrangements can also coordinate charging with local generation, building demand or energy-market services. Smart charging is broader than load balancing. Load balancing focuses on sharing constrained electrical capacity, while smart charging can respond to a wider set of signals and objectives.

Charging & Electrical Engineering

Smart meter

A smart meter records energy use and communicates readings through the smart-meter communications system rather than relying only on manual meter readings. In Great Britain, the installation normally includes an electricity meter, communications hub and in-home display. A smart meter is not simply an electricity meter connected to the public internet. The communications hub sends and receives information over the secure smart-meter network. Smart-meter data can support time-of-use tariffs used for EV charging, while the EVSE can have its own separate energy meter for charging control or billing.

Charging & Electrical Engineering

Solid-state battery

A solid-state battery uses a solid electrolyte instead of the liquid or gel electrolyte found in conventional lithium-ion cells. The term covers several possible solid-electrolyte materials and cell architectures. Research programmes are pursuing higher energy density, improved safety and faster charging, but performance depends on the specific chemistry and cell design. Those benefits should not be treated as guaranteed characteristics of every solid-state battery. Solid-state technology is moving through development and manufacturing scale-up. The glossary should therefore avoid fixed commercialisation dates or performance claims tied to one prototype.

Battery & Energy Storage

State of charge

Also called: SoC, SOC State of charge is an estimate of how much usable charge remains in a battery, normally expressed as a percentage of the available capacity. It performs the same practical job as a fuel gauge in a combustion vehicle. SoC is estimated by the battery-management system from measurements and models rather than measured directly as a simple liquid level. Voltage, current, temperature and battery history can all contribute to the estimate. Charging power often changes with SoC. Many EVs accept their highest DC charging power in part of the lower or middle SoC range and reduce power as the battery approaches full charge.

Battery & Energy Storage

State of health

Also called: SoH, SOH State of health is an estimate of a battery's condition relative to a defined reference state, usually when the battery was new. It can reflect changes in usable capacity, power capability or other performance measures, depending on the manufacturer's method. SoH is not the same as state of charge. A battery can be at 100% SoC while having less usable energy than it had when new because its state of health has declined. There is no single universal calculation used by every vehicle or battery manufacturer. SoH values should therefore be interpreted alongside the method used to derive them.

Battery & Energy Storage

Supercharger

A Tesla Supercharger is a high-power DC charge point on Tesla's global charging network. Tesla vehicles use the network with account and vehicle integration through Tesla's ecosystem. Selected Supercharger sites are also open to compatible non-Tesla EVs. In the UK, Tesla lists sites where other EVs with CCS compatibility can charge through the Tesla app. "Supercharger" is a Tesla brand name rather than a generic technical category. Other networks may offer similar or higher charging power under different brands. T

Operations & Infrastructure

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TEN-T

Also called: Trans-European Transport Network TEN-T is the European Union's trans-European transport network covering major transport corridors, nodes and connections across Europe. AFIR uses the TEN-T road network as a basis for binding EV charging-infrastructure deployment targets. The regulation sets requirements for charging pools serving light-duty and heavy-duty vehicles at specified intervals and with minimum power levels as the network develops. TEN-T is therefore a location and infrastructure-planning concept rather than a charging technology. Its relevance to an EVSE supplier comes from where AFIR requires charging capacity to be deployed.

Standards, Safety & Compliance

Tethered cable

A tethered charging cable is permanently attached to the charge point. The driver connects the fixed cable directly to the vehicle rather than carrying a separate cable for that session. Tethering makes the connector type and cable length part of the charge point design. Those choices affect vehicle compatibility, cable management and accessibility. Socketed AC charge points take the opposite approach, providing a socket so the user supplies a detachable charging cable.

Connectors & Charging Modes

Thermal management

Thermal management controls the temperature of an EV battery, power electronics and other components so they operate within suitable limits. Systems can use liquid cooling, air cooling, refrigerant circuits, heaters or combinations of these approaches. Battery temperature affects available charging power, discharge power, ageing and safety protection. The BMS uses temperature information when setting allowable limits. Thermal management is therefore part of both driving and charging performance, particularly at high DC charging power.

Battery & Energy Storage

Three-phase charging

Three-phase EV charging uses all three phases of an AC electrical supply to transfer power to a compatible vehicle. It is common on commercial sites and can support higher AC charging power than an equivalent single-phase connection. The vehicle needs a three-phase-capable onboard charger to use all three phases. A three-phase charge point does not force every vehicle to draw three-phase power; the actual charging arrangement depends on the vehicle and EVSE. Site design also needs to consider balance between phases, particularly where several single-phase chargers share a three-phase supply.

Charging & Electrical Engineering

Three-pin plug

A UK three-pin plug is a BS 1363 domestic mains plug used by some portable Mode 2 EV charging cables. IET guidance describes Mode 2 charging from this type of socket as typically operating at 10 A or less. The portable charging lead contains in-cable control and protection functions. The domestic plug and socket do not provide those EV-specific functions themselves. Long-duration EV charging places a sustained load on the circuit, so the socket and electrical installation need to be suitable for that use.

Connectors & Charging Modes

TLS

Also called: Transport Layer Security Transport Layer Security, or TLS, protects network communications by providing confidentiality, data integrity and endpoint authentication. EV charging systems use TLS to protect connections between networked components such as charging stations and management systems. OCPP 2.x includes security profiles that use TLS. OCPP certification requires Security Profile 2 in the Core for OCPP 2.x, while advanced security can use client-side certificates for mutual authentication. TLS protects data in transit. It does not replace controls such as secure boot, signed firmware or certificate management on the device itself.

Cybersecurity & Firmware

Total cost of ownership

Also called: TCO Total cost of ownership, or TCO, adds the costs of buying, operating and supporting an asset across a defined period. For EV charging infrastructure, that can include hardware, installation, grid connection, software, payment services, energy, maintenance and field support. Purchase price alone can understate the cost of a charger if reliability or support problems create repeated site visits and lost charging revenue. TCO comparisons need the same operating period and assumptions to be meaningful.

Operations & Infrastructure

Trickle charger

Trickle charging is an informal term for charging at very low power. In EV discussions it is sometimes used for domestic-socket charging, although that charging method is more accurately described by its charging mode and power. "Trickle charger" also has a separate established meaning in low-voltage battery maintenance, where a charger supplies a small current to maintain a battery. For traction-battery charging, use terms such as Mode 2, Mode 3 and the actual kW rating where technical precision matters.

Charging & Electrical Engineering

Turtle mode

Turtle Mode is a reduced-power state used by some electric vehicles when the battery or another vehicle condition limits the propulsion power available. A turtle or similar warning symbol can appear on the driver display. Low state of charge is one common trigger, but manufacturer logic can also reduce power because of battery temperature or other protection conditions. The available speed, power and remaining range vary by vehicle. Drivers should follow the vehicle warning and manufacturer's instructions rather than treating Turtle Mode as a normal operating mode.

EV & Vehicle Terminology

Type 1 connector

Also called: SAE J1772 connector, J-plug Type 1 is an AC vehicle connector configuration associated with SAE J1772 and used mainly in North America and on some older imported EVs elsewhere. It is designed for single-phase AC charging. The connector carries AC power along with signalling contacts used for charging control and connection detection. In CCS1, the related Combo 1 vehicle inlet adds two large DC contacts beneath the Type 1 interface. Type 1 should not be confused with the SAE J1772 document itself. J1772 is the North American standard that defines the conductive charging method and coupler requirements; Type 1 describes the connector configuration.

Connectors & Charging Modes

Type 2 connector

Also called: IEC Type 2, Mennekes-style connector Type 2 is the AC EV charging connector configuration widely used in Europe and standardised under IEC 62196-2. It can support single-phase or three-phase AC charging, depending on the vehicle, EVSE and electrical supply. The current IEC 62196-2:2025 edition covers AC charging accessories up to 480 V AC, with ratings up to 63 A three-phase or 70 A single-phase across the standardised configurations. Type 2 also forms the upper part of the European CCS Combo 2 vehicle inlet. That lets one vehicle inlet accept a Type 2 connector for AC charging or a Combo 2 connector for DC charging. U

Connectors & Charging Modes

U

UFC

Also called: ultra-fast charging UFC is an older abbreviation for ultra-fast charging, used for very high-power EV charging. It is not the current UK government label for a defined public-charging power band. Department for Transport statistics now use "ultra-rapid" for public charge points rated at 150 kW and above. For specifications, state charging power in kW rather than relying on UFC, ultra-fast or ultra-rapid terminology alone.

Charging & Electrical Engineering

Ultra Low Emission Zone

Also called: ULEZ The Ultra Low Emission Zone, or ULEZ, is London's road-charging zone for vehicles that do not meet specified emissions standards. It is not a zone reserved for zero-emission vehicles. Compliant petrol and diesel cars can travel in the ULEZ without paying the ULEZ charge. For M1 passenger cars, TfL states that the NOx standard is equivalent to Euro 4 for petrol cars and Euro 6 for diesel cars, with an additional particulate-matter requirement for diesel. Battery electric vehicles meet the relevant tailpipe-emissions standard, but other London road charges can still apply separately.

Standards, Safety & Compliance

Ultra-low emission vehicle

Also called: ULEV An ultra-low emission vehicle, or ULEV, is a UK classification currently used for vehicles reported to emit less than 75 g/km of tailpipe CO2. The category can include several powertrain types rather than one specific vehicle technology. Battery electric and fuel cell vehicles meet the tailpipe CO2 threshold, while some plug-in hybrids and other low-emission vehicles can also qualify. ULEV is a policy and statistics term rather than a synonym for EV. Where a grant, tax or regulatory rule uses the term, use the definition and eligibility criteria published for that particular scheme.

EV & Vehicle Terminology

Uptime and reliability

EV charger uptime and reliability describe how consistently charging equipment remains usable over time. Operators often track these measures using charger or EVSE status data, although commercial KPI definitions can differ. UK Public Charge Point Regulations set a specific reliability requirement for a CPO's rapid public network. Public charge points rated 50 kW and above must achieve at least 99% reliability on average across that network over each calendar year. The UK calculation uses OCPI EVSE object statuses and defined exemptions. A general marketing claim such as "99% uptime" is therefore not automatically the same metric as statutory network reliability. V

Operations & Infrastructure

V

V2G PKI

Also called: Plug & Charge PKI, Public Key Infrastructure V2G PKI is the certificate and trust infrastructure used by ISO 15118 Plug & Charge to authenticate participating vehicles, contracts and charging systems. It provides the chain of trust behind the automatic authorisation seen by the driver. Contract certificates identify the charging contract presented by the vehicle. Other certificates are used within the wider system so that software can verify who issued a certificate and whether it should be trusted. CharIN maintains certificate policies for first-generation PKI aligned with ISO 15118-2 and second-generation PKI aligned with ISO 15118-20. The PKI is part of the implementation around Plug & Charge, rather than the charging connector itself.

Cybersecurity & Firmware

V2X

Also called: vehicle-to-everything V2X is an umbrella term for vehicle-to-everything energy use cases in which an EV can provide electrical energy beyond normal one-way charging. It includes vehicle-to-grid, vehicle-to-home and vehicle-to-building applications. The exact boundary of V2X terminology varies across the industry, so the specific destination for exported power should be stated where possible. ISO 15118-20 supports communication for bidirectional power transfer, but a working V2X system also depends on compatible power electronics, installation design and local grid rules.

Grid & Energy Management

Vehicle Excise Duty

Also called: VED, vehicle tax Vehicle Excise Duty, or VED, is the UK tax charged on vehicles according to the rules that apply to their type and registration date. Electric, zero and low-emission vehicles became liable for VED from 1 April 2025. For 2026/27, a zero-emission car first registered on or after 1 April 2025 pays £10 in its first year and then the £200 standard rate. Other registration cohorts have different treatment. VED rates change, so a glossary definition should explain the tax and date any figures rather than presenting a current rate as permanent. The government has also announced a separate mileage-based Electric Vehicle Excise Duty from April 2028.

Standards, Safety & Compliance

Vehicle-to-building

Also called: V2B Vehicle-to-building, or V2B, lets compatible EVs supply electrical energy to a commercial or other building through bidirectional charging equipment. The stored vehicle energy becomes one controllable asset within the site's electrical system. V2B can be used to reduce site peaks, support local loads or coordinate with generation and stationary storage. The available energy depends on how many vehicles are connected and how much charge their operating schedule allows the site to use. Building export, islanding and network-interconnection requirements still depend on the electrical design and local rules. The term describes the use case, not automatic permission to operate it.

Grid & Energy Management

Vehicle-to-grid

Also called: V2G Vehicle-to-grid, or V2G, allows a compatible EV and bidirectional charging system to export electrical energy back towards the public electricity network. It can turn parked vehicles into controllable energy resources when the vehicle owner and system operator permit it. V2G can support services such as demand shifting, aggregation or grid balancing, depending on market rules. ISO 15118-20 supplies the vehicle-to-EVSE communication needed for modern bidirectional power-transfer control. In Great Britain, exporting equipment can also bring G99 connection requirements and G100 export limitation into scope. V2G is therefore a grid-connection project as well as a charger feature.

Grid & Energy Management

Vehicle-to-home

Also called: V2H Vehicle-to-home, or V2H, lets a compatible EV supply electrical energy to a home through bidirectional charging equipment. The vehicle battery can support household loads when the system is configured for that use. Depending on the installation, V2H can support self-consumption, tariff optimisation or backup operation. Backup capability requires an electrical design that can isolate and supply the intended circuits safely when the grid is unavailable. V2H is distinct from V2G because the immediate destination is the premises rather than an export service to the public network.

Grid & Energy Management

Voltage

Voltage is the electrical potential difference between two points and is measured in volts. In an EV charging system, voltage is one of the quantities that determines the power transferred to the vehicle. Battery packs and DC chargers operate across defined voltage ranges. A charger can supply high current and still be unable to deliver its headline power if the connected vehicle's battery voltage is too low for that power level. Vehicle architectures are often described loosely as 400 V or 800 V systems. Those labels refer to nominal architecture families rather than one fixed voltage throughout every operating condition. W

Charging & Electrical Engineering

W

WLTP

Also called: Worldwide Harmonised Light Vehicle Test Procedure WLTP is the laboratory test procedure used to produce comparable vehicle energy-consumption, CO2 and electric-range figures. It replaced the older NEDC procedure for new light-duty vehicle type approval in Europe. WLTP creates standardised comparison figures under controlled test conditions. Real-world EV range can be higher or lower depending on speed, temperature, terrain, heating or cooling and driving style. A WLTP range figure should therefore be treated as a repeatable test result, not a promise that every driver will cover that distance between charges.

Standards, Safety & Compliance

Workplace charging

Workplace charging provides EV charging at a place of work for employees, visitors or fleet vehicles using the site's electrical infrastructure. Charging power and access arrangements vary with dwell time, fleet needs and site capacity. A workplace with several charge points may need load balancing so charging demand does not exceed the available electrical capacity. The charging system can also use access control, scheduling or billing depending on who is allowed to charge. Private workplace charge points sold in Great Britain can fall under the Electric Vehicles (Smart Charge Points) Regulations 2021. Publicly accessible workplace chargers can have different regulatory obligations.

Charging & Electrical Engineering

Workplace Charging Scheme

Also called: WCS The Workplace Charging Scheme is an OZEV grant that contributes towards the purchase and installation of EV charge points at eligible workplaces. The grant is claimed by an authorised installer after the applicant receives a voucher. From 1 April 2026, the maximum grant increased to £500 per socket, with support for up to 40 sockets across an applicant's sites. The scheme has been extended for a final year until 31 March 2027. These figures are time-sensitive. A live glossary page should retain the review date and link to GOV.UK so readers can check whether the scheme has changed. X Y Z

Standards, Safety & Compliance

Z

Zero emission

Zero emission usually describes a vehicle or activity with no emissions at the point of use, such as no tailpipe CO2 from a battery electric vehicle. In EV policy, the phrase often refers to tailpipe emissions. A battery electric vehicle does not emit CO2 or NOx from an exhaust while driving because it has no combustion exhaust. That does not mean the complete lifecycle has zero emissions. Vehicle manufacturing, electricity generation and other upstream activities can still produce greenhouse-gas emissions. Use ZEV when referring to a formal zero-emission vehicle classification.

EV & Vehicle Terminology

Zero-emission vehicle

Also called: ZEV A zero-emission vehicle, or ZEV, is a vehicle classified as producing zero tailpipe CO2 under the relevant regulatory or statistical definition. In current UK vehicle statistics, the category includes battery electric and fuel cell electric vehicles. "Zero emission" in this context is a tailpipe classification. It does not mean that vehicle manufacture, electricity production or hydrogen production has no environmental impact. The UK's Vehicle Emissions Trading Schemes use a specific regulatory ZEV definition based on 0 g CO2/km under WLTP and other qualifying requirements. The exact legal definition should be checked when the term is used for compliance rather than general explanation.

EV & Vehicle Terminology

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400 V / 800 V architecture

400 V and 800 V describe nominal high-voltage EV architecture families rather than one fixed battery voltage. Actual pack voltage changes with cell chemistry, state of charge and vehicle design. For the same electrical power, increasing voltage allows lower current. Lower current can reduce resistive losses and the conductor size or cooling burden needed for high-power charging. An 800 V vehicle still needs the charging system to operate across its required voltage range. Charger power depends on both voltage and current capability.

Charging & Electrical Engineering

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The EV charging glossary

Browse the glossary A to Z

A

A/C

AC

AC and DC charging

Ad hoc charging

AFIR

Agreed export capacity

Agreed import capacity

Alternative fuel vehicle

Autocharge

Autopilot

Availability

B

B2U

Battery

Battery capacity

Battery cells

Battery degradation

Battery Energy Storage System

Battery lease

Battery management system

Battery preconditioning

Benefit in Kind

BEV

Bidirectional charging

BS 7671 Section 722

Building Management System

C

C-rate

CAN bus

Car club

CHAdeMO

Charge flap

Charge Point Operator

Charging capacity

Charging curve

Charging Detail Record

Charging point

Charging rate

Charging station

Cheetah stance

CO2

Combined Charging System

Commando socket

Commissioning

Connector

Connector type

Contactless payment

Control pilot

Cost per kWh

CPMS

CSMS

Current transformer

Customer Limitation Scheme

CVT

Cyber Resilience Act

D

DC

Demand response

Depreciation

DER

Destination charging

DIN SPEC 70121

Distribution Network Operator

Dynamic load management

E

e-Pedal

E-REV

Eco mode

Economy 7

Eichrecht

Electric Highway

Electric Vehicle Homecharge Scheme

eMSP

EV

EVCC

EVSE

EVSE ID