What a portable power station will actually run

One page per appliance, each working from the same arithmetic: usable watt hours after inverter losses, divided by average draw rather than peak. Two appliances of the same rated wattage can give wildly different run times, and the reason is almost always how much of the time they actually draw power.

PowerStationFacts takes part in the Amazon Services LLC Associates Program. When you buy through a link on this page we may earn a commission, and the price you pay does not change.

RefrigeratorA fridge averages about 40 W once the compressor duty cycle is taken into account, so the battery lasts far longer than the rating plate suggests.CPAP machineA small load that runs all night, and a heated humidifier that quietly doubles it. The sizing question is nights, not watts.Router and modemThe smallest load on the site, and the one where the inverter's own idle draw costs more than the appliance does.Chest freezerThe kindest large appliance on the list: a low average draw, a lid that traps cold, and thermal mass that buys you hours for nothing.Sump pumpA heavy motor that runs in short bursts. Sizing is decided by the start-up surge and by how hard it is raining, not by watt hours.TelevisionA modest continuous load that grows fast once the soundbar, the box and the console join it on the same battery.LaptopThe one appliance where the right answer is to avoid the mains socket altogether and charge over USB-C.MicrowaveThe number on the front of the oven is cooking output, not what it pulls from the socket. Size on input, and count minutes rather than hours.Space heaterThe honest answer is short: no battery in this catalogue heats a room for a night. Here is the arithmetic, and what to do instead.Induction hobA heavy continuous load that is only ever on for minutes. Size it by the meal, not by the day.Portable air conditionerA compressor load with a thermostat, which helps, and an appetite that still empties the largest battery here before morning.

Why the rated wattage is only half the answer

A fridge and a space heater can carry the same figure on their plates and behave nothing alike. The heater draws that power continuously until you switch it off. The fridge runs its compressor until the cabinet is cold, stops, and starts again when it drifts, which across a day works out at roughly a third of the time.

That difference is worth more than any battery specification. Treat a fridge as a continuous load and you will conclude a kilowatt hour unit dies in half a day; treat it properly and the same unit runs it well past a full day. Each page below states which assumption it uses.

Start-up current, the other thing plates do not tell you

Anything with a motor pulls several times its running wattage for a fraction of a second when it starts: fridges, freezers, sump pumps, power tools. A unit whose continuous output only just covers the running figure can still trip on that spike. This is what surge ratings exist for, and it is why continuous output matters more than capacity when the load has a motor in it.

For your own appliance, the run time calculator lets you enter its real wattage and shows every assumption on screen.