Power It Up: running a chest freezer through an outage
Chest freezers use less energy than fridges. See how far a portable power station goes with one, using the EnergyGuide label.
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A chest freezer rated 300 kWh/yr averages about 820 Wh a day, or 34 W. A 1kWh-class station runs it for roughly a day at that example figure, and because a full freezer holds temperature for about 48 hours when closed, you can run it in shifts.
- Daily Wh = EnergyGuide kWh/yr × 1,000 ÷ 365.
- Keep the lid closed between shifts.
- Running it a few hours at a time stretches any battery.
What a chest freezer draws
| Item | Example figure | Where it comes from |
|---|---|---|
| EnergyGuide figure (example) | 300 kWh/yr | Read your own label |
| Daily energy | ≈822 Wh/day | 300,000 ÷ 365 |
| Average draw | ≈34 W | 822 ÷ 24 |
| Start-up surge | Several times running watts | Compressor motor |
How we do the math
Runtime (hours) ≈ usable watt-hours ÷ the device's average watts. Our reference set is five portable power stations whose specs we compiled in the Spec Check series. Estimated usable AC energy (our estimate: usable ≈ rated Wh × 0.80 (usable depth, Victron LiFePO4 data) × 0.92 (inverter, the NREL PVWatts manual derate) ≈ 0.736. Applying these to a power station gives a planning estimate, not a measurement): RIVER 3 ≈180Wh, DELTA 3 ≈754Wh, Anker C1000 ≈777Wh, Jackery 1000 v2 ≈788Wh, BLUETTI AC180 ≈848Wh.
Every device wattage on this page is an example. Read your own device's label or EnergyGuide sticker, or measure it with a plug-in energy meter, then put your number into the Power Planner.
Runtime on each reference station
| Power station | Est. usable Wh | Est. runtime |
|---|---|---|
| EcoFlow RIVER 3 | ≈180 | Not suitable (300W outlet too small for a compressor) |
| EcoFlow DELTA 3 | ≈754 | ≈22.2 h |
| Anker SOLIX C1000 | ≈777 | ≈22.9 h |
| Jackery Explorer 1000 v2 | ≈788 | ≈23.2 h |
| BLUETTI AC180 | ≈848 | ≈24.9 h |
The smallest station that fits
The DELTA 3 is the smallest reference station by capacity that also has a large surge rating (3,600W) for the compressor start. At the example figure it covers close to a day. The BLUETTI AC180 has the most estimated usable energy of the group.
EcoFlow DELTA 3 (1,024Wh)
About a day at the example figure, high surge rating, expandable.
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BLUETTI AC180 (1,152Wh)
The most estimated usable Wh in our reference set.
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FoodSafety.gov says a full freezer holds a safe temperature for about 48 hours if the door stays closed (about 24 hours if half full). Running the freezer a few hours at a time, then letting it coast, can make a battery last across a longer outage. Use a freezer thermometer to check.
FAQ
Will a power station start my freezer's compressor?
Compressors draw a brief surge at start-up. Pick a station whose surge rating is several times the freezer's running watts, and check the freezer manual for its start-up figure.
Where do I go next?
Try the power planner to put numbers to your own situation, or see the product picks on the deals page.
Terms used here
- Watt (W)
- Rate of power use or production.
- Watt-hour (Wh)
- Energy: one watt for one hour.
- Kilowatt-hour (kWh)
- 1,000 watt-hours.
- Depth of discharge (DoD)
- Share of a battery's capacity that is used.
- LiFePO4 (LFP)
- Lithium iron phosphate battery chemistry.
- Inverter
- Converts DC battery power to AC household power.
- Surge rating
- Short-term peak power an inverter can supply.
- Derate
- Factor for real-world losses in solar output.
Sources
This guide is informational and based on published specifications and general references, not hands-on testing. Check the manufacturer's current specs before you buy.