EV charging basics and glossary
This glossary explains the words you meet when you charge an electric car or run a charging network: kW and kWh, AC and DC, plug types such as Type 2, CCS, GB/T and NACS, and the protocols OCPP, OCPI and ISO 15118. Each entry is one or two sentences, with a link to a longer guide where there is one.
Energy and power
kW (kilowatt)
A measure of power, how fast energy flows. A 7 kW charger delivers up to 7 kWh in an hour.
kWh (kilowatt-hour)
A measure of energy, the unit you pay for and the size of a battery. A 60 kWh battery holds 60 kWh. See the cost calculator.
State of charge (SoC)
How full the battery is, in percent.
Range
How far the car goes on a charge. It falls in cold weather and on mountain roads.
Types of charging
AC charging
Alternating current from the station goes to the car’s on-board charger, which limits the speed. Common, slower, good for stops of an hour or more. All EV Armenia points are AC.
DC fast charging
Direct current goes straight into the battery, much faster, up to hundreds of kW. Needs more grid power.
Wall box
A small AC charger fixed to a wall, for home or business. See home charging.
Idle fee
A charge for staying plugged in after charging has finished, usually after a grace period.
Connectors
Type 1 (J1772)
A single-phase AC connector common on American and some Asian cars.
Type 2 (IEC 62196-2)
The European AC connector, single- or three-phase, up to 63 A.
CCS (Combo)
Type 1 or Type 2 plus two DC pins. CCS2 is the European version, CCS1 the American one.
CHAdeMO
A Japanese DC standard used by older models such as the Nissan Leaf.
GB/T
The Chinese standard, with separate AC and DC versions. GB/T DC is not directly compatible with CCS. See Chinese EVs.
NACS (SAE J3400)
The connector developed by Tesla for AC and DC, now standardised as SAE J3400. See Tesla charging.
The full comparison is in connector types in Armenia.
Protocols and business terms
OCPP
Open Charge Point Protocol, the standard language between a charger and its management software. See OCPP explained.
CSMS
Charging station management system, the back-end software. See what is a CSMS.
CPO
Charge point operator, the company that runs the chargers.
eMSP
E-mobility service provider, the company that gives drivers an account, app and payment.
OCPI
Open Charge Point Interface, a protocol that lets operators and service providers exchange data for roaming.
ISO 15118 and Plug and Charge
A standard for communication between car and charger. Plug and Charge lets the car authenticate itself automatically.
Smart charging
Controlling charging power over time or between connectors, for example to stay within a site’s limit.
V2X / V2G
Vehicle-to-everything or vehicle-to-grid: the car sends energy back. Supported by newer standards such as OCPP 2.1.
Roaming
Using one network’s account to charge at another network’s stations.
Questions and answers
What is the difference between kW and kWh?
kW is power, how fast; kWh is energy, how much. A 7 kW charger running for an hour delivers 7 kWh.
What is the difference between AC and DC charging?
AC goes through the car’s on-board charger and is slower; DC goes straight to the battery and is faster.
What does OCPP mean?
Open Charge Point Protocol, the open standard for communication between chargers and management software.
Sources
Ready to charge?
Open the map, pick a charger and see the price before you start. No account needed.