Running a Fridge Through a Power Outage — What Each Battery Size Actually Buys

Before buying anything, know the baseline. US food-safety guidance is that a refrigerator holds a safe temperature for about 4 hours if you keep the door closed, and a full freezer for about 48 hours (24 hours if half full).

The single most effective thing you can do during an outage is not open the door. That is free, and it beats any battery.

Not what the label says. A refrigerator's compressor cycles on and off, so the figure that matters is the running average.

A typical full-size household fridge rated at 150 W therefore consumes roughly 52 watt-hours per hour. A 12 V compressor camp fridge averages about 45 W.

Two caveats. Duty cycle rises in a warm house — during a summer outage with no air conditioning, expect closer to 45–50% and size accordingly. And the compressor draws several hundred watts for a fraction of a second when it starts, so the unit's surge rating matters even though the running draw is small.

Calculated from independently measured usable capacity at a 52 W average — assumptions here.

Note that these are usable figures, not ratings. To convert to a rating to shop by, divide by about 0.85 — or better, use a unit with a published measurement.

The fridge is rarely the only thing you want during an outage. Add the realistic rest of it and the numbers change sharply:

A chest freezer is generally easier than a refrigerator, not harder. It is better insulated, opened less, and its duty cycle is often lower once at temperature — typically 40–60 W average for a domestic chest freezer.

The catch is the starting surge, which is usually larger than a fridge's. Check the unit's surge rating, and be aware that surge claims are not always reliable — one independent test recorded a shutdown at 3,140 W against a 3,900 W claim.[2]

Plug in before the outage, not during. Several units here specify UPS switchover between 10 and 30 ms, and the Bluetti AC70's was independently measured at 14 ms.[3] With the fridge permanently plugged into the power station and the power station plugged into the wall, an outage causes no interruption at all.

Do not run it through the wall. Connecting a battery to house circuits needs a transfer switch and, in most US jurisdictions, a licensed electrician. An extension lead to the fridge is a purchase; backfeeding a panel is an installation.

Recharge matters as much as capacity. If power returns briefly, a unit that refills in 54 minutes recovers a full charge where one taking three hours recovers a third.[4]

Keep it charged. A backup at 40% is not a backup.

For the full ranking by measured capacity see the best power stations, or work out your own total with the sizing guide.