What Size Power Station for a 12V Fridge?

This is the most commonly over-sized purchase on the site, and it happens for a specific reason: people read the household-refrigerator figure, apply it to a camping fridge, and buy three times the unit they need. A 12V compressor fridge and a kitchen refrigerator are different appliances with different physics, and the gap between them is about 800Wh a day.

Why a 12V fridge is so much cheaper to run

• It is smaller. 40-75 litres against 400-600 litres of cabinet to keep cold.
• It is better insulated for its size. A camping fridge is built to hold temperature in a hot car, which is a harder brief than a kitchen appliance faces.
• It has a DC compressor. No inverter in the path when you run it from a 12V socket, which removes the 15-20% conversion loss a household fridge on a power station always pays.
• It cycles less in cool conditions. A fridge in a shaded van at 70F has a much lower duty cycle than the same fridge in a 100F car.

The exception worth naming is a thermoelectric or Peltier cooler, which is a completely different device despite looking similar. Those draw continuously rather than cycling, and they are far more expensive to run than a compressor fridge of the same size. If your cooler has no compressor, every figure on this page is optimistic — check which type you own.

The arithmetic

Read the plate on your own fridge for its running wattage, and then be honest about the duty cycle you will actually see. Ambient temperature is the biggest variable by a wide margin, and the figures above are a worked example rather than a measurement of your appliance. How many watt-hours does a refrigerator use covers how to measure a duty cycle properly if you want your own number.

The sizing table

For most people the honest answer is the 1kWh class: two days of fridge with the phones, lights and a laptop evening alongside, and a weekend is the trip most people actually take. If your trips are longer, the fix is usually a panel rather than a bigger battery — see below.

The surge question, which is smaller here

A 12V compressor still demands more current at start than it does running, but the absolute numbers are far smaller than a household fridge's. Where a 150W kitchen fridge can ask for 600-1,200W at start-up, a 45W camping fridge's inrush sits well inside the smallest inverters here. That is why a 286Wh unit with 600W of continuous output runs one without complaint, where the same unit cannot start a kitchen refrigerator at all. Can a power station run a refrigerator covers the household case where surge genuinely decides it.

Solar makes this load disappear

A 12V fridge is the one significant load that a single portable panel can genuinely cover. A 200W panel at five peak sun hours and a 0.75 derate delivers roughly 750Wh a day, against a 432Wh fridge — which means in reasonable sun the fridge runs indefinitely and the surplus charges everything else.

That is the reason best solar generator for a refrigerator splits its advice by fridge type: 100-200W of panel for a 12V unit, 400-500W for a household one. How much solar input do you need has the derate reasoning, and how long to charge a power station with solar covers the refill time.

Five practical savings

1. Run it on DC. The 12V socket rather than the AC inverter. Worth 15-20% for nothing.
2. Keep it out of the sun. Ambient temperature drives the duty cycle more than any setting does.
3. Pre-chill at home. Arrive with the fridge and its contents already cold and the first day's draw drops sharply.
4. Fill it. A full fridge holds temperature between compressor cycles; a half-empty one cycles more.
5. Open it less. Every opening dumps cold air, and on a 40 litre box that is a meaningful fraction of the contents.

Which unit, and where this fits

For a weekend with a fridge, best power station for a camping fridge is the commercial shortlist built on exactly this arithmetic. For a van where the fridge runs permanently, what size power station for van life adds the rest of the build — and once a diesel heater, lights and a water pump are in the total, the fridge is still the biggest single line.

On a boat the same numbers apply with a weather caveat: best power station for a boat notes that no unit in this registry publishes a water-ingress rating, so the battery has to live somewhere dry even though the fridge does not.

What we have not done

We have not metered a 12V fridge, and the 40-60W and 30-50% duty-cycle figures are category bands rather than measurements of your appliance — read your own plate and, if the purchase is large, measure a day with an energy meter. Every power-station figure is the manufacturer's published specification, linked below. How we choose.