How long will a power station run my fridge?
About 14 hours per 1,000 Wh for a typical full-size fridge. Here is where that number comes from, and a calculator for your fridge and your station.
A fridge is the appliance most people want to keep running in an outage, and it is also the one that confuses people most. The label on the back says something like 120 V, 6 A. That is 720 W. But a fridge does not draw 720 W all the time. The compressor runs for a few minutes, then rests. Averaged over a day, a modern full-size fridge uses about 1.2 to 1.6 kWh, which works out to 50 to 70 W on average.
The math
Battery size is in Wh Watt-hours. Battery size. How much energy is stored. 1,000 Wh runs a 100W device for about 8.5 hours after losses.. Divide by the average watts and you get hours. Then take off about 15%, because the station loses some energy turning battery power into wall power.
Your fridge, your station
Why the compressor start matters
When the compressor kicks on it pulls 3 to 5 times its running power for a fraction of a second. That is the surge number on a station. A 600 W station with a 1,200 W surge handles a normal fridge. A 300 W station may not.
The timeout trap
Some stations switch their AC outlets off by themselves when the load is small or comes and goes. A resting fridge looks like that kind of load. EcoFlow, for example, says its AC outlets can turn off with an on-and-off load like a fridge unless the AC timeout is set to Never in the app. On any station, look for an AC timeout or auto-off setting and, if there is one, set it to Never.
Rules of thumb
- Keep the door shut. Every opening lets cold air out and makes the compressor run again sooner.
- A full fridge holds cold longer than an empty one.
- For more than a day, add a solar panel or plan to recharge from the car.