Electric Vehicle Charging Glossary & Technical Terminology

A reference guide to essential electrical and automotive terms used throughout our calculators:

Kilowatt-Hour (kWh):: The standard unit of electrical energy measurement. In electric vehicles, battery pack capacity is measured in kWh (analogous to the gallon capacity of a gas tank).
Kilowatt (kW):: The rate of electrical power transfer. Charger speeds and motor power outputs are expressed in kW. One kilowatt equals 1,000 watts.
State of Charge (SOC):: The current energy level of the vehicle’s battery pack expressed as a percentage from 0% (empty) to 100% (fully charged).
Level 1 Charging (120V):: Charging via a standard 120-volt household AC outlet at 12 to 16 amps (delivering 1.4 kW to 1.9 kW), adding 3 to 5 miles of range per hour.
Level 2 Charging (240V):: Charging using a 240-volt single-phase AC circuit (such as a NEMA 14-50 or hardwired wall connector) delivering 7.7 kW to 19.2 kW, adding 25 to 45 miles of range per hour.
DC Fast Charging (DCFC / Level 3):: Commercial high-voltage direct current charging supplying 50 kW to 350 kW directly to the battery, bypassing the onboard AC rectifier to recharge 10% to 80% in 18 to 35 minutes.
NACS (North American Charging Standard / SAE J3400):: The standardized vehicle charging connector developed by Tesla, now adopted across major automotive manufacturers in North America.
Time-of-Use (TOU) Rate:: A utility tariff pricing structure where electricity rates fluctuate depending on the time of day, offering significant discounts during overnight off-peak periods.