EV Range Added per Hour of Charging

How many miles of driving range an hour of charging adds.

Run the calculator

Example

You enter

EVSE power (kW, e.g. 7.7) 7.7
Charge efficiency (0-1, ~0.88) 0.88
Vehicle efficiency at the battery (mi/kWh; an EPA sticker figure is wall-based, so set charge efficiency to 1 with it) 3.5
Target range to add (mi) 100

You get

Range added 23.716
Hours to add the target 4.217

Checked against published worked examples from: NREL.

Details, formula, and sources

ScopeThe number that sizes an EVSE to a commute or a fleet's daily miles. Range per hour = EVSE power (kW) x charge efficiency x the vehicle's efficiency (mi/kWh): the kilowatts delivered, after the ~10-15% AC losses, times how far the car goes per kWh. A 7.7 kW Level 2 charger at 88% on a car getting 3.5 mi/kWh adds ~23.7 mi of range per hour, so a 100-mile commute replenishes in ~4.2 hr, comfortably overnight. A 9.6 kW circuit adds range proportionally faster, but the vehicle's ONBOARD charger caps the AC rate, and a less efficient vehicle (truck / cold weather) adds fewer miles/hr. A steady AC Level 2 estimate; DC fast charging tapers, and the onboard-charger limit and actual efficiency govern.

Formula or tablerange_added_mi_per_hr = evse_power_kw x charge_efficiency x vehicle_efficiency_mi_per_kwh; hours_to_add_target = target_range_mi / range_added_mi_per_hr.

Source and editionEV range-added-per-hour of AC Level 2 charging (energy identity; SAE J1772 onboard-charger limit), by name; the vehicle's onboard charger and actual efficiency govern.

Free accessThe range-per-hour relation is a public energy identity; the EVSE power, charge efficiency, and the vehicle's mi/kWh are the charger and vehicle values the user supplies.

What governsEstimate. AHJ and licensed professional govern.

API field namesevse_power_kw, charge_efficiency, vehicle_efficiency_mi_per_kwh, target_range_mi, range_added_mi_per_hr, hours_to_add_target

Range-per-hour identity range/hr = EVSE kW x charge efficiency x mi/kWh; hours = target range / (range/hr)energy identity
Onboard-charger cap AC rate is capped by the vehicle's onboard charger (a bigger EVSE does not charge faster, see ev-charge-time); DC fast charging tapers separatelySAE J1772 / vehicle spec