Portable Fridge Power Consumption Explained: Watts, Ah/h and Wh per Day

Fridge listings are full of power numbers that look precise and mean different things: “45 W”, “8.5 A”, “0.57 Ah/h”, “165 Wh/24h”. If you add a battery or solar based on the wrong one, you’ll either overspend or run out. This explainer sorts out what each number means, how to convert between them, what independent testers measured, and why most bars in our own power chart are labeled as estimates. We haven’t measured these fridges ourselves.

Why doesn’t a “60 W” fridge use 60 W?

Because a compressor fridge doesn’t run all the time. It runs until the inside reaches the set temperature, shuts off, and starts again when the temperature creeps up. Gear Diary watched this on an ICECO VL60 running from a power station’s DC outlet: about 70 W at start-up, 56–58 W while the compressor ran, and 0 W when it cycled off.

So two numbers matter:

• Rated (or maximum) input is the most the fridge will draw, usually at start-up or in a fast-cooling mode. Dometic says to think of it as the maximum current the unit would ever draw, and to use it for sizing wiring and fuses.
• Average draw is what the fridge uses over hours, counting the off time. This is the number for battery and solar sizing.

Dometic’s CFX3 45 shows the gap clearly. It’s rated at 8.2 A on DC, about 98 W at 12 V. Its published average is 1.03 Ah/h at 90°F outside and 39°F inside, about 12 W. The average is roughly an eighth of the rating.

Dometic’s FAQ shows the logic with an older CFX model: about 3.75 A while running, times the share of time the compressor is on (22% in its example), gives an average under 1 Ah per hour.

What do Ah/h, W and Wh mean?

These are the units you’ll see, and how to convert:

A worked example with real published numbers. EcoFlow rates the GLACIER Classic 35L at 0.57 Ah/h in fridge mode (77°F outside, 39°F inside, Eco mode):

• 0.57 × 12 ≈ 6.8 W average.
• 6.8 × 24 ≈ 164 Wh a day. EcoFlow’s own spec says 165 Wh per 24 hours, so the figures agree.
• In freezer mode, EcoFlow publishes 1.8 Ah/h, or 520 Wh a day. That’s about three times as much.

Batteries and power stations use different units, which is where people trip up. A 12 V battery is rated in Ah. A power station is rated in Wh. A 100 Ah LiFePO4 battery is about 1,280 Wh, while a “300 Wh” power station is roughly the same as a 23 Ah battery. Our battery runtime guide does the full math, including how much of each battery is usable.

Why do some specs mention 24 V or AC?

Most fridges run on 12 or 24 V DC and on 100–240 V AC. The current halves at 24 V for the same power. Dometic lists the CFX5 55IM at 8.5 A on 12 V and 4.0 A on 24 V. AC ratings (55 W for that fridge) describe the wall side and don’t translate directly to battery use. Some listings mix these up. The Euhomy 59 Quart listing gives a 45 W “average power consumption”, but OutdoorGearLab measured 9.2 W at steady state. For battery planning, look for a 12 V Ah/h figure with its test temperatures, and be skeptical of anything else.

What have independent testers measured?

OutdoorGearLab logged power for every cooler it tested. The steady-state numbers are useful for comparing fridges, but OutdoorGearLab doesn’t state the ambient temperature, so we don’t treat them as ratings.

Two lessons. First, insulation and compressor design matter: the Anker EverFrost 2 40L and the CFX5 platform sip power once cold. Second, thermoelectric coolers are in a different league. The Igloo drew about ten times as much as the compressor fridges and still never reached 40°F. See compressor vs thermoelectric.

Real camping uses more than a lab steady state. Gnomad Home logged an ICECO VL35 ProS over 123 hours of real use and measured about 508 Wh a day, roughly 1.76 A average. That’s what lid opening, warm food and hot afternoons do.

Why is our power chart mostly estimates?

Because makers rarely publish a comparable average draw. In our data:

• Only the EcoFlow GLACIER Classic 35L publishes a fridge-mode average draw with test conditions.
• Dometic publishes figures for the CFX5 sizes we feature, but not in fridge-only mode. The CFX5 55IM’s 1.55 Ah/h includes the ice maker running. The CFX5 75DZ’s 2.76 Ah/h has one zone freezing. Using them would make those fridges look worse than fridge-only rivals, so our chart uses a fridge-only estimate instead.
• ICECO publishes MAX-mode wattages (45 W for the VL45 ProS, 57 W for the VL75 ProD). Its manual notes the data is only suitable for laboratory testing. These are not averages.
• Most budget brands publish a single rated wattage and nothing else.

So for every fridge without a usable published average, we estimate from size. At 90°F outside and 39°F inside, we use 110 Wh + 3.4 Wh per liter per day, plus 20% for dual zones. We calibrated that on the published figures we do have: Dometic’s CFX3 45 (about 297 Wh), Dometic’s rating for the CFX5 45 (about 248 Wh), and the GLACIER Classic scaled to 90°F (about 219 Wh). Then we scale every figure to the chart’s 90°F/37°F condition by the temperature gap. Thermoelectric coolers are the exception: they run flat out, so we use their full draw all day. That’s why the Igloo isn’t on the chart at all. By our estimate it uses about 1,490 Wh a day.

What this means for you: the chart is good for comparing sizes and types, and a rough guide to battery needs. It isn’t a measurement of any one fridge. If you need precision, measure your own with a shunt monitor like the Victron SmartShunt, or use the Dometic app’s energy graph, which Dometic says shows consumption when running on DC.

What changes how much power a fridge uses?

• Outside temperature. The biggest factor. Scaled from Dometic’s figure, a 45-quart fridge uses nearly twice as much at 100°F as at 70°F.
• Set temperature. Dometic recommends 39°F for refrigeration and notes that even small changes in setting affect consumption.
• Freezer mode. About three times fridge mode, per EcoFlow’s figures.
• Sun, ventilation and placement. See our hot weather tips.
• Lid opening and warm food. Each adds pull-down work.
• Eco vs Max mode. Eco usually runs the compressor slower or the fan less. Anker’s runtime claims for the EverFrost 2 are all in Eco mode.

Bottom line

Ignore the headline watts for battery planning. Look for a 12 V average in Ah/h with its test temperatures, convert it to Wh a day, and scale for your weather. Where a maker doesn’t publish one, which is most of them, our chart gives a size-based estimate you can use as a starting point. Put any of them into the battery runtime calculator to see what it means for your battery and solar.