12V Fridge Power Consumption: How Many Amp-Hours a Day?

Dometic publishes the clearest figures: its CFX3 45 uses 1.03 Ah per hour at 32 C ambient and 4 C inside, and its CFX3 100 uses 1.56 Ah per hour at 90 F ambient and 39 F inside. Over 24 hours at those conditions, that is about 24.7 Ah and 37.4 Ah from a 12V battery. Cooler weather and fewer door openings bring it down.

Daily use from the maker's figure

Dometic product pages; 24-hour totals are our arithmetic
Fridge	Ah per hour (maker test)	Ah per 24 h at that condition
Dometic CFX3 45 (46 L)	1.03 at 32 C ambient, 4 C inside	24.7
Dometic CFX3 100 (99 L)	1.56 at 90 F ambient, 39 F inside	37.4

What changes it

Ambient temperature: Dometic tests in hot conditions, so cooler days use less.
Setpoint: freezing uses more than chilling.
Door openings and warm food added.
Ventilation around the compressor.

Battery protection

Dometic says its CFX models use a 3-stage battery protection system that monitors incoming DC voltage. Budget models such as the EUHOMY 23 Qt list 3-level battery protection (per the Amazon listing).

Sizing the battery

Dometic's FAQ for the CFX3 100 recommends a minimum 40 Ah battery with a 100 W or larger solar panel. For several days off-grid, multiply the daily figure by the days you want to cover, plus whatever else draws power. Fridges with Dometic-style figures are in best 12V fridges; CFX3 100 is sold direct.

Two zones

Dual-zone fridges run longer to hold a freezer section: see dual-zone 12V fridges.

Frequently asked questions

How many amps does a 12V fridge draw?

Dometic lists 1.03 Ah per hour for the CFX3 45 and 1.56 Ah per hour for the CFX3 100 under its test conditions; the compressor cycles, so the draw averages out.

How long will a 12V fridge run on a battery?

Divide usable battery capacity by daily use. At about 24.7 Ah a day, a fridge like the CFX3 45 uses roughly a quarter of a 100 Ah battery's capacity daily in hot weather.

What size battery do I need for a 12V fridge?

Dometic recommends a minimum 40 Ah battery for the CFX3 100 alongside a 100 W or larger solar panel; more if you want several days without charging.

Does a 12V fridge use more power in summer?

Yes. Dometic tests at hot ambient temperatures, and use rises with heat and door openings.

Will a 12V fridge kill my van battery?

Most compressor fridges have low-voltage cutoffs; Dometic's CFX models use 3-stage battery protection.

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