Home charging glossary

kW (kilowatt). A rate: how fast energy flows. A charger's power. Volts times amps, divided by 1,000.

kWh (kilowatt-hour). An amount: what your utility bills and what a battery holds. One kW for one hour is one kWh.

kWh per 100 miles. How much energy a car uses to go 100 miles. Lower is more efficient. It is printed on the fueleconomy.gov label.

EVSE (electric vehicle supply equipment). The wall unit or cordset. It does not charge the battery itself: it checks the connection and tells the car how much current it may draw.

Onboard charger. The part inside the car that turns AC from your wall into DC for the battery. Its rating caps Level 2 speed.

Level 1 / Level 2. 120-volt and 240-volt AC charging at home. DC fast charging is the roadside kind and is not a home installation.

Continuous load. A load that runs three hours or more. EV charging is treated as one, which is where the rule that a charger may draw 80 percent of its breaker comes from.

NEMA 14-50. A 240-volt, 50-amp receptacle, the most common plug-in Level 2 outlet. See plug-in or hardwired.

J1772 and NACS (SAE J3400). The two connectors on North American cars. See connectors.

Load calculation. The arithmetic an electrician does to decide whether your service can take another big circuit. See panel capacity.

Time-of-use rate. A utility plan that prices electricity by the hour. See charging on a schedule.