What can a 1,000 Wh battery run during an outage?
A 1,000 Wh rating describes stored energy, not a promise that a particular appliance will run for a fixed number of hours. Real runtime depends on the output path, inverter losses, battery reserve, and the appliance’s changing demand.
Reviewed October 23, 2026 · How we review guides
Start with a realistic usable-energy estimate
For illustration, if 85% of a 1,000 Wh rating is available to the inverter and the inverter is 90% efficient, about 765 Wh reaches AC loads in this simple model. Actual products vary; use the product’s published usable capacity and efficiency when available.
The remaining energy is not necessarily wasted. Some is held as a battery reserve, and some is lost while converting battery power to AC. DC and USB outputs may have different conversion losses.
Runtime depends on average load
Divide delivered watt-hours by the average watts used. In the example above, a steady 50 W load would use about 765 Wh in 15.3 hours. A 150 W load would use it in about 5.1 hours.
Those examples assume a constant load. Refrigerators cycle, routers and lights have their own draw, and many devices use more power during startup. Use measured consumption where possible.
Check power limits as well as runtime
The station must support the load continuously, and it must handle a motor’s startup surge. Add together the devices you may run at the same time, then compare that figure with the station’s rated AC output. Confirm surge duration and output limits in the manual.
Never run a fuel-burning generator indoors or in an enclosed space. Follow official carbon monoxide guidance and the instructions for any equipment you use.