How long will a power station run it?

Enter the battery capacity and the average watts your devices draw. We allow for about 15% inverter and battery losses.

Capacity (Wh)

Average load (W)

Efficiency (%)

Or start from an appliance

Enter a capacity and a load.

Runtime for common appliances

Estimated runtime on portable power stations
Appliance	500 Wh	1,000 Wh	2,000 Wh	3,000 Wh
Refrigerator60 W average	7.1 h	14.2 h	28.3 h	42.5 h
Chest freezer24 W average	17.7 h	35.4 h	70.8 h	106.2 h
Mini fridge32 W average	13.3 h	26.6 h	53.1 h	79.7 h
CPAP machine22 W average	19.3 h	38.6 h	77.3 h	115.9 h
TV80 W average	5.3 h	10.6 h	21.2 h	31.9 h
Starlink90 W average	4.7 h	9.4 h	18.9 h	28.3 h
Wi-Fi router and modem15 W average	28.3 h	56.7 h	113.3 h	170 h
Window air conditioner396 W average	1.1 h	2.1 h	4.3 h	6.4 h
Portable fridge21 W average	20.2 h	40.5 h	81 h	121.4 h
Electric blanket50 W average	8.5 h	17 h	34 h	51 h

Hours = capacity × 0.85 ÷ average watts. Fridges and freezers cycle, so their average is well below the running watts.

The formula

Runtime (hours) = battery capacity (Wh) × efficiency ÷ load (W). Inverters lose some energy turning battery DC into 120 V AC, and most power stations keep a small reserve, so about 85% of the rated capacity is a fair planning figure. For appliances that cycle, such as fridges and freezers, use the average draw over a day, not the running watts. The runtime guide works through examples.