What size power station runs a refrigerator, and for how long?

The duty cycle is most of the answer

This site works from 120 W as a standing figure for a full size fridge, inside a range of 80 W to 200 W that depends on cabinet size, age and efficiency class. No fridge draws that continuously. The compressor pulls the cabinet down to temperature, shuts off, and restarts when the temperature drifts back up. Across a normal day in a normal room it is actually running about 35% of the time.

That leaves an average draw near 42 W. Add the conversion loss between the battery and the mains socket, which this site assumes at 85% because almost no maker publishes a figure, and an hour of refrigeration costs a station roughly 49 Wh. Treat the same fridge as a continuous 120 W load instead and the answer comes out about four times worse. Both numbers are arithmetically correct; only one answers the question people are actually asking. The run time calculator puts both assumptions on screen and lets you move them.

Two things push the real duty cycle up, and both are within your control during an outage: a warm room, and a door that keeps opening.

The same fridge on three sizes of station

Each table below applies the same assumptions to a different capacity. The fridge row is the one to read here; the others are there for scale.

Small, roughly a kilowatt hour

Mid sized, around two kilowatt hours

Large, four kilowatt hours and expandable

The gap between them is linear, because the arithmetic is linear: double the usable capacity and you double the hours. What is not linear is what each unit can start, and that is the next section. A unit near the bottom of this range keeps a fridge cold for the length of a typical evening outage. A unit near the top keeps it cold long enough that the food is no longer the problem.

Surge: why a station that fits on paper still trips

A compressor motor pulls several times its running wattage for a fraction of a second as it starts. A station whose continuous rating only just covers 120 W can still shut down on that spike. This is what surge ratings are for: Anker SOLIX C1000 Gen 2 is rated 2,000 W continuous and 3,000 W on surge, and that headroom is the part doing the work here.

One distinction matters and is easy to miss. A surge rating is a brief tolerance of start-up current. It is not the same thing as EcoFlow X-Boost or BLUETTI Lifting Power, which run a load above the nominal rating by lowering the output voltage. That trick suits a resistive load such as a kettle or a heating element. It is the wrong tool for a motor, and it should never be the reason you expect a compressor to start.

Older fridges start harder than recent ones. If yours is elderly, or if it is a side by side with an ice maker, buy the surge headroom rather than hoping.

Three units that suit a fridge

7.0/10

C1000 Gen 2 Anker SOLIX C1000 Gen 2

1,024 WhCapacity2,000 WAC output24.9 lb (11.3 kg)Weight10 msUPS switchover

Check price on Amazon›Full specs and verdict

7.7/10

Elite 200 V2 BLUETTI Elite 200 V2

2,073.6 WhCapacity2,600 WAC output53.4 lb (24.2 kg)Weight15 msUPS switchover

Check price on Amazon›Full specs and verdict

6.7/10

DELTA 3 EcoFlow DELTA 3

1,024 WhCapacity1,800 WAC output27.6 lb (12.5 kg)Weight10 msUPS switchover

Check price on Amazon›Full specs and verdict

Anker SOLIX C1000 Gen 2 is the honest entry point: enough surge headroom for a domestic compressor, 10 ms switchover so the fridge never notices the mains dropping, and a weight of 24.9 lb (11.3 kg) that one person can move to wherever the fridge is.

BLUETTI Elite 200 V2 is the one to pick if the goal is an outage lasting more than a night. Its 2,073.6 Wh is double the entry class, its cells are rated 6,000 cycles to 80%, and it takes 1,000 W of solar, which is what turns a fixed number of hours into a fridge that keeps running while the sun is up.

EcoFlow DELTA 3 earns its place on switchover rather than size: 10 ms is fast enough that the fridge is simply never off, and Expandable to 5,000 Wh means the runtime is not fixed at purchase. Compare the two lines directly on C1000 Gen 2 against DELTA 3.

Cut the load before you buy more battery

Capacity is the expensive way to buy hours. These are the cheap ways.

• Keep the door shut. Every opening replaces cold air with room air and the compressor pays for it. A fridge left alone through an outage runs a far lower duty cycle than one that is checked every hour.
• Fill the empty space. Bottles of water in the fridge and frozen packs in the freezer hold temperature between compressor runs, which lengthens the off periods.
• Run the fridge alone. An inverter left on with nothing else plugged in still draws a few watts. Sharing the station with a kettle or a heater costs hours you wanted for food.
• Plug in before the outage, not during. A unit with a UPS function sits between the wall and the fridge and takes over on its own. You are not woken up and the compressor is not restarted cold.
• Add a panel. A fridge is a small enough average load that a modest solar input can offset most of a day of it.

Then read the plate on your own fridge

The wattages here are common starting points, not measurements of your appliance. The rating plate, usually inside the door frame or on the back, gives the figure that applies to you. If it quotes amps rather than watts, multiply by the mains voltage to get a working number.

Two further corrections are worth making before you trust an estimate. Cold cuts usable capacity, and most units refuse to charge below freezing at all, which makes a winter outage the worst case on both counts. And a cycle rating is quoted to a percentage of original capacity, commonly 80%, sometimes 70%, so a unit near the end of its rated life is meeting its specification while delivering noticeably less than it did new. The method behind these figures sets out every assumption the site makes.