How much battery and solar does a 12V compressor fridge need?

Answered by RV Parts Giant · Upland, CA · October 11, 2026

Short answer: Our calculator counts a 12V compressor fridge at 25Ah a day. With the basic loads of lights, pump, phone charging and fans, that is about 550Wh a day: a 150Ah LiFePO4 battery and 150W of solar for two days off-grid. A big fridge in hot weather can draw far more, so size for your worst week, not your best.

A compressor fridge is usually the biggest load that runs all day and all night, so it sets the size of most small systems. Here is what our calculator does with it.

The figures the calculator uses

Load	Amp-hours a day (12V)
12V compressor fridge	25
Lights, water pump, phone charging, vent fans	18
Total	43Ah, about 550Wh

The math uses a 12V bank, 85% usable LiFePO4 capacity and 75% real-world solar harvest, with about five peak sun hours unless you choose otherwise.

Battery and solar

Days off-grid and sun	Battery	Solar	Controller
2 days, mixed sun	150Ah	150W	MPPT 75/15 or 100/20
3 days, mixed sun	200Ah	150W	MPPT 75/15 or 100/20
3 days, cloudy (about 3 peak hours)	200Ah	250W	MPPT 100/30

No inverter: the fridge runs on 12V directly.

Swapping a propane fridge for a compressor fridge

An absorption fridge on propane only draws about 3Ah a day for its controls. Swap it for a compressor fridge and the same basic setup goes from 269Wh to 550Wh a day. For two days that takes the battery from 100Ah to 150Ah and the solar from 100W to 150W.

The hot-weather check

The 25Ah figure is an average. Our fridge buying guide notes that a well-insulated 50L fridge might average 30 to 45Ah a day in mild conditions and double that in 35°C heat. Put 45Ah into the same formula and the answer for two days becomes 150Ah and 250W:

Daily use: 45 + 18 = 63Ah, about 806Wh.
Battery: 63 x 2 / 0.85 = 148Ah, so 150Ah.
Solar: 806Wh / 5 sun hours / 0.75 = 215W, rounded up to 250W.

So the battery holds up, but the array needs more. If you camp in summer heat with a larger fridge, size the panels for the hot case.

Measure your fridge

A SmartShunt on the battery shows the real daily draw in a day or two. Swap your measurement in for the 25Ah and the calculator gives you an exact build.

Run your own numbers in our RV solar & battery calculator: choose "It runs on battery only (12V compressor fridge)" and add the rest of your loads.