How many watt-hours is a 1kWh battery?

A 1kWh battery is about 1.0 kWh (996 Wh nominal). On LiFePO4 roughly 757 Wh is usable; on lead-acid about half is.

What can a 1kWh battery run?

A 1kWh LiFePO4 battery (~757 Wh usable) can run, for example, a 150W refrigerator for about 5.0 hours, or LED lights (40W) for about 18.9 hours.

Battery capacity

What can a 1kWh battery power?

A 1kWh LiFePO4 battery holds about 1.0 kWh, of which roughly 757 Wh is usable. Here is roughly how long it runs common devices — adjust any load in the calculator below.

Device	Typical power	Run-time
Refrigerator	150 W	5.0 hours
CPAP	45 W	16.8 hours
TV	90 W	8.4 hours
Laptop	50 W	15.1 hours
LED lights	40 W	18.9 hours
Space heater	1500 W	0.5 hours
Ceiling fan	60 W	12.6 hours
Router	12 W	63.1 hours

Calculate for your device

Battery capacity (Ah)

Battery voltage (V)

Device load (W)

Chemistry

Run-times assume LiFePO4 (~80% usable) and typical inverter loss. Lead-acid of the same rating gives roughly 60% as long, since only ~50% is usable. To build a full system, use the system calculator.

Estimates for planning only. See the methodology.