Electric car words, explained

22 September 2026 · 6 minute read

The words on a charger's screen, a car's page and every forum thread, in plain terms. Where a longer guide exists, the entry links it.

Power and energy

kW (kilowatt). Power: how fast energy moves. A charger's kW is how fast it can charge; a motor's kW is how strong it is.
kWh (kilowatt hour). Energy: an amount. A battery holds so many kWh, a car uses so many per 100 km, and a charger sells them. One kW for one hour is one kWh.
kWh per 100 km, miles per kWh. Efficiency. Under 15 kWh per 100 km (over 4 miles per kWh) is good; over 20 is thirsty.
AC and DC. Alternating current is what the grid supplies and slow chargers deliver; the car converts it. Direct current is what the battery stores and fast chargers deliver straight in. See charging speeds.
Single and three phase. How a building's electricity arrives. Three phase allows 11 or 22 kW AC charging; single phase allows about 7.

State of charge (SoC). How full the battery is, as a percentage. The fuel gauge.
State of health (SoH). How much of the battery's original capacity remains. A five year old car is typically at 90% or more. See buying used.
Usable and gross capacity. The kWh you can use, and the kWh in the pack. Cars keep a buffer at the top and bottom to protect the cells.
LFP. Lithium iron phosphate, a battery chemistry that is cheap, long lived and happy at 100%, and a little heavier for its energy.
NMC, NCA. Nickel based chemistries: lighter and longer ranged for their size, and best kept between 20 and 80% day to day.
Buffer, reserve. The part of the battery the car keeps back, or the part you keep back. The planner's reserve is yours.
Degradation. The slow loss of capacity with age and use. A few percent early, then under 2% a year.
Preconditioning. The car warming (or cooling) its battery before a fast charge so it can charge at full speed. See cold weather.

Level 1, 2 and 3. The North American names for a household socket, AC charging and DC fast charging.
Fast, rapid, ultra fast. DC charging. On ChargeAlong, fast is 50 to 149 kW and ultra fast is 150 kW or more; the UK says rapid for the first.
Charging curve. How a car's charging power changes as the battery fills: high when low, tapering towards full. The shape matters more than the peak. See how long to charge.
10 to 80. The band a road trip charges in, and the time quoted for it, because charging above 80% is slow.
CCS2, CCS1, Type 2, Type 1 (J1772), CHAdeMO, NACS, GB/T. The plugs. See plug types.
Tethered and untethered. A charger with its own cable, or a socket you bring a cable to. Most AC posts are untethered; all DC chargers are tethered.
Idle fee. A charge per minute for staying plugged in after the car is full, to keep bays moving.
Plug and charge. The car identifies itself to the charger and the account linked to it is billed, with no app or card.
RFID. A card or fob tapped on a charger to start a charge, tied to a network account.
Roaming. Using one network's account or app to charge on another's, often at a higher price.
ICEd. A charging bay blocked by a petrol or diesel car (an internal combustion engine).

Regen, regenerative braking. The motor slowing the car and putting the energy back in the battery. It is why town driving beats highway driving for range.
One pedal driving. Strong regen when you lift off, so the brake pedal is rarely needed.
Onboard charger. The part of the car that converts AC to DC, and sets the AC charging limit: 7, 11 or 22 kW.
Heat pump. A cabin heater that moves heat rather than making it, and saves winter range.
V2L, V2H, V2G. Vehicle to load, home and grid: using the car's battery to run appliances, a house, or feed the grid.
800 volt. A higher voltage battery system that charges faster and loses less energy as heat.
WLTP, EPA, NEDC. Test cycles a rated range is measured on. EPA is the most realistic, WLTP is common in Europe and Australia, NEDC is old and optimistic. See real range.
BEV, PHEV, hybrid. A battery electric car; a plug in hybrid with a small battery and a petrol engine; a hybrid you cannot plug in.

Network, operator, CPO. The company that runs the charger and sets its price.
Site, station. A place with one or more chargers. ChargeAlong pages are per site.
Charger, unit, EVSE. One machine at a site, often with two cables.
Bay. The parking space at a charger.
OCPP. The open protocol chargers use to talk to their network, which is what lets an app start a charge and see its power.
Open Charge Map, OCM. The open register of charging sites most of ChargeAlong's data comes from. See where the data comes from.
Uptime. How often a charger works when you arrive. The number networks are judged on, and the reason to read a site's recent reviews.