What size power station for a 12V fridge?

By the Ferncharge team · Figures last checked 18 October 2026

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The short answer: find your fridge's average consumption in amp-hours per hour (Ah/h), which Dometic publishes for its compressor cool boxes, and multiply by 12 to get average watts. For example, Dometic's UK site states 0.76 Ah/h at 12 V for the CFX5 45 (at 32 °C outside, 4 °C inside), which is about 9.12 W on average (Dometic UK). From a power station's 12 V socket, a 500 Wh model works out at roughly 46 hours and a 1,000 Wh model about 93 hours on our assumptions.

Compared on manufacturers' published specs. Ferncharge has not tested these products. Estimates only.

Work out the size for your cool box (opens the sizing calculator with a 12 V compressor cool box at 9.12 W, 24 hours a day; set your own days and figures).

Average draw vs rated current: the key difference

Dometic explains that its energy consumption figure (Ah/h) is the average the unit uses at a given outside and inside temperature, while the rated input current is the maximum it would ever draw (Dometic product FAQ). For runtime, use the average. To check the socket, use the rated current.

How long will a power station run a 12V fridge?

Runtime (hours) ≈ capacity (Wh) × 0.855 ÷ average watts from the 12 V socket (LiFePO4: 90% usable × 95% DC conversion; see methodology).

Rounded down. Dometic's own example compares a thermoelectric cooler at 47 W (3.92 Ah/h) with a compressor cooler averaging under 1 Ah/h (Dometic), which is why compressor models last much longer on a battery.

What changes it: Dometic notes that even small changes in the inside temperature setting affect consumption, and advises keeping the cooler full, the lid closed as much as possible, and the vents clear. Its stated figure is at a hot 32 °C ambient. In cooler UK weather, consumption may be lower, but Dometic doesn't publish a UK-weather figure on this page, so we plan with the stated one. Dometic UK also lists a minimum operating temperature of 16 °C for the CFX5 45, so check the manual before relying on it in a cold tent or van.

Check the 12 V socket

The power station's car-style socket must handle the fridge's rated current. Stated ratings (alphabetical):

• Anker SOLIX C1000: car charger output 12 V 10 A (Anker UK user guide); 120 W max (Anker SOLIX UK)
• BLUETTI AC180: 12 V/10 A car outlet, regulated (BLUETTI UK)
• EcoFlow RIVER 3: car output 12.6 V, 10 A, 126 W max (EcoFlow UK)
• Jackery Explorer 1000 v2: car port 12 V 10 A (Jackery user manual)

All four are stated at 10 A, above the CFX5 45's stated 9.4 A rated current at 12 V, though not by much. More models in the spec table. Current prices are on the makers' UK product pages: Anker SOLIX UK product page, BLUETTI UK product page, EcoFlow UK product page, Jackery UK product page.

Dometic also advises against splitters and extension leads on the 12 V lead, because they add voltage drop (Dometic FAQ).

12V or mains socket?

Running a dual-voltage cool box from the 12 V socket avoids the inverter (we assume a 10% loss on AC). Dometic UK lists the CFX5 45's rated AC input power as 43 W, a maximum figure, not an average.

A household fridge in a power cut

A household fridge typically uses 40–120 W (Energy Savers) and runs from the mains socket, with a compressor start-up surge. See power stations for power cuts.

Recharging while you go

Solar panels or charging while driving can top the power station up. How much depends on the panel, weather and season. Use the solar fields in the sizing calculator.

FAQs

How long will a power station run a fridge?

Divide the usable energy by the fridge's average watts. A 1,000 Wh power station running a compressor cool box averaging 9.12 W from the 12 V socket works out at about 93 hours on our assumptions.

What size power station do I need for a 12V fridge for a weekend?

For 48 hours at 9.12 W average from the 12 V socket, about 440 Wh of energy plus losses: roughly 510 Wh rated capacity, before any safety margin. Our calculator adds a 20% margin.

Why does my fridge's rated current look so high?

It's the maximum, used for checking sockets and wiring. The average consumption (Ah/h) is usually much lower, because the compressor cycles on and off.

Are thermoelectric cool boxes OK on a power station?

They work, but they draw power continuously. Dometic's example is 47 W, so they use the battery much faster than a compressor model.

Related: Camping · Campervan · Runtime calculator · Safety