Power Station Runtime Calculator
Enter a power station’s capacity and pick a device, and the calculator estimates how long it will actually keep that device running — after the losses that shrink real-world runtime below the sticker math.
How it works
Runtime is not simply capacity divided by watts. Only about 85% of a battery's rated watt-hours are usable, and converting DC into AC gives up a little more, so the honest figure is lower than a quick division suggests.
Most appliances also cycle rather than run flat out. A fridge compressor switches on and off; the calculator uses each device's typical duty cycle, so the hours reflect how it really behaves instead of a worst-case constant draw.
Frequently asked questions
How long will a 1,000Wh power station run a refrigerator?
Roughly 12–18 hours for a typical fridge, because it only runs about a third of each hour. A chest freezer or an over-full fridge lands at the lower end. Enter 1000 above and pick your device for a closer estimate.
Why is the runtime shorter than capacity divided by watts?
Because raw division ignores losses. Batteries deliver about 85% of their rated capacity usefully, inverters give up a little converting to AC, and the result is real hours rather than lab math. Planning to the raw number is how people end up in the dark early.
Can a power station run a space heater or air conditioner?
It can, but not for long. A 1,500W heater drains a 1,000Wh station in well under an hour, and high-draw heating and cooling are the fastest way to empty a battery. For heat during an outage, most people plan around a fuel generator or a non-electric backup.
Does the duty cycle really matter that much?
Hugely. A fridge rated at 150W that runs a third of the time uses a third of the energy a constant 150W load would. Ignoring duty cycle can throw a runtime estimate off by two or three times, which is why the calculator builds it in.