Runtime calculator
What will a power station run — and for how long?
Tick the devices you want to keep on, adjust the watts and hours if you know them, and we'll check all 20 power stations: can they start and run everything, how long they last, and how much solar it takes to refill them.
How we calculate
Energy per device = watts × hours × quantity × duty cycle (fridges, freezers and pumps only run part of the time). Stations deliver about 85% of their rated watt-hours to AC devices after inverter losses, so we use that.
Output and surge
Output assumes everything you ticked runs at once, the worst case. Surge checks the biggest motor start (fridge, pump, AC) on top of everything else. If a station's surge rating isn't published, we use its continuous output.
Solar
We assume 4.5 peak sun hours a day and panels delivering 75% of their rating, typical for much of the US. Stations can't use more solar than their maximum input.
Frequently asked questions
How do I calculate how long a power station will last?
Multiply the station's capacity in Wh by 0.85 (inverter losses), then divide by your devices' combined watts. A 1,000 Wh station running 100 W lasts about 8.5 hours.
How many watts does a refrigerator use?
A typical full-size fridge runs at 100–200 W but only about a third of the time, averaging 1–1.5 kWh a day. It needs 600–1,200 W for a moment to start its compressor.
What size power station do I need for a CPAP?
About 400 Wh per night without the heated humidifier and 800 Wh per night with it, after losses.