Storage

12V Fridge Power Draw Calculator

Estimate how much power a 12V compressor fridge uses each day, and how long your battery could run it.

A compressor fridge doesn't run all the time. It cycles on and off, so its daily use depends on how long the compressor runs. This works out the daily energy and amp-hours, and how many days a battery could run the fridge on its own. Everything is worked out in your browser. Nothing is saved or sent anywhere.

1. Your fridge

Use the running watts and how much of the day the compressor runs, or the maker's daily figure if they give one.

The draw while the compressor runs, from the label or manual.
Higher in hot weather, with warm food going in, or when it's opened often. A battery monitor can measure it.
Check what temperatures the maker tested at.

2. Your battery

Used to estimate how many days the battery could run the fridge alone, with no charging.

Use the maker's recommended depth of discharge. 80% for lithium and 50% for AGM are common starting points.

3. Results

How it was worked out

    What this does and doesn't tell you

    • This is an estimate. A fridge's real use changes with the weather, the set temperature, how full it is, how often it's opened and where it sits.
    • Makers' daily figures are usually measured in set conditions. Expect more in hot weather.
    • Days on the battery assume the fridge is the only load and nothing is charging. Add your other loads with the Daily Energy Use & Battery Size Calculator.
    • Keep the fridge's cable short and thick enough, because voltage drop can make it cut out early. Check it with the 12V Voltage Drop Calculator.
    • Work on 240V AC wiring, including inverter outputs and mains inlets, must be done by a licensed electrician. For high-current DC gear such as inverters, DC-DC chargers and battery links, follow the maker's installation manual and have an auto electrician check your work if you're unsure.

    Next steps

    Add the fridge to everything else you run with the Daily Energy Use & Battery Size Calculator. Then work out the solar to keep up with it in the Solar Panel Sizing Calculator. Running it from a power station? Try the Power Station Runtime Calculator.

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