What Size Power Station to Run a Refrigerator? Runtime Math That Actually Works (2026)

The refrigerator is the #1 load people buy power stations for — and the #1 load people size wrong. The mistake is almost always the same: someone buys a big battery and forgets the compressor’s startup surge, or buys a punchy little inverter and discovers it empties in four hours. Here’s the quick answer, the math, and a runtime table for all 12 models we cover.

The quick answer

Full-size fridge: you need about 1kWh of station capacity per 6–8 hours of runtime. A 2kWh station (our recommended minimum for real backup) runs a full-size fridge ~11–12 hours — through a typical overnight outage.

Mini-fridge: about 1kWh per 14–15 hours. The little guys are easy.

The catch: the fridge’s compressor surges to 800–1,200W for 1–3 seconds every time it starts. The station’s surge rating must be higher than that, or the inverter trips the moment the compressor kicks on — no matter how big the battery is. Every model in our table below clears it; stations below ~600W surge don’t.

The math: watts, hours, and the 0.85

Runtime follows one formula:

Runtime (hours) = Capacity (Wh) × 0.85 ÷ Average watts

The 0.85 accounts for inverter losses (~10%) plus a margin for not draining the battery to absolute zero. Your two inputs:

Average watts — the running draw, not the label. Fridges cycle: the compressor runs 30–50% of the time under normal conditions. A fridge drawing 150W while the compressor runs averages out to roughly 50–75W over the day — but for outage sizing, plan on the warmer end (hot kitchen, door opened more often) and use ~100–150W average for a full-size fridge, ~60W for a mini-fridge, ~80W for a chest freezer. When in doubt, plug in an energy meter for 24 hours — the daily kWh it reports is the single most reliable number you can get.

Startup surge — 3–6× the running draw, lasting 1–3 seconds. Full-size: typically 800–1,200W. This is the number that trips undersized inverters. Always check the station’s surge (peak) rating against it.

Note one more hidden load: frost-free fridges run a defrost heater (300–700W for 15–30 minutes, on a timer). It’s within every station’s rating here, but it adds to the day’s total Wh. If you want the full capacity-vs-output framework this builds on, read our sizing guide.

Runtime table: all 12 models, full-size fridge (~150W average)

Calculated as capacity × 0.85 ÷ 150. Real-world runtimes run a bit longer if the door stays closed and a bit shorter in a hot kitchen. Every model here has surge headroom for the compressor’s 800–1,200W startup spike.

Mini-fridge (~60W average) — multiply the full-size numbers by about 2.5×. The 1kWh class gets you ~14–15 hours; the 2kWh class ~29 hours; the F3000 ~43 hours. The Anker SOLIX C1000 is the natural pick here: light (28.4 lb), cheap relative to the class, and its 2,400W SurgePad rating has headroom for anything a mini-fridge throws at it.

The surge gotcha, in detail

This deserves its own section because it’s where sizing fails. A fridge compressor at startup draws its locked-rotor current — a brief spike of 3–6× the running draw. Real-world measured numbers:

• Mini-fridge (50–80W running): 200–600W surge. Nearly any station handles it.
• Small full-size, 15–18 cu ft (~100W running): 500–700W surge. Needs ≥700W peak rating.
• Mid full-size, 19–22 cu ft (~150W running): 800–1,200W surge. Needs ≥1,200W peak rating.
• Large French-door, 23–26 cu ft (~200W running): up to 1,200–1,800W surge. Needs ≥1,800W peak rating.

Practical consequence: a large French-door fridge on a DJI Power 1000 is fine (4,400W surge). The same fridge on a hypothetical 500W/1,000W-peak station is not fine — it has plenty of Wh for hours of runtime but trips instantly at compressor start. Always compare your fridge’s surge to the station’s peak rating, not its continuous watts. If your fridge is the large French-door type, the DELTA 2 Max or Explorer 2000 Plus (4,800W and 6,000W surge respectively) buy you real margin.

Older fridges surge harder and run less efficiently than ENERGY STAR models — a 15-year-old fridge can easily draw 50% more than its modern equivalent. If yours is old, round your average up toward 200W.

Mini-fridge vs full-size vs chest freezer

Mini-fridge (dorm/office, ~60W average, 200–600W surge): any 1kWh station works. The 1kWh class is lighter, cheaper, and does double duty for camping. Our pick: the SOLIX C1000. See the budget power station guide for the full 1kWh field.

Full-size fridge (~150W average, 800–1,200W surge): the 2kWh class is the sweet spot — ~11–12 hours of runtime, enough for most outages, at a reasonable weight (~42–50 lb). Either the SOLIX C2000 Gen 2 or the DELTA 2 Max (the DELTA 2 Max charges faster from solar at 1,000W vs 800W).

Chest freezer (~80W average, 600–1,000W surge): freezers run longer per kWh than fridges because they’re opened less — ~18 hours per 1kWh. But if you’re backing up fridge + freezer together, size them as one ~250W combined load: you want the 3kWh class (SOLIX F3000, ~17 hours combined runtime) or the 4kWh flagships — the DELTA Pro 3 and SOLIX F3800 give ~22–23 hours combined. Compare those two directly in our flagship head-to-head.

Solar top-up for multi-day outages

A battery only covers day one. For outages past ~24 hours, the station has to recharge faster than the fridge drains it — roughly 150W average drain means you need ~150W of sustained solar production to break even, and realistically 400W+ of panels to recover ground. Two things matter:

1. Solar input wattage of the station — the 1kWh units cap out at 500–800W, fine for fridge-only duty; the flagships take 2,400–2,600W, enough to recharge a whole day’s fridge use in a couple of hours of sun.
2. Panel sizing to your roof/yard — our solar pairing guide and the /tools/solar-pairing/ tool size panels to each model, including how many watts you need to keep a fridge neutral through a cloudy day.

Rule of thumb: pair any fridge-backup station with at least 2× the fridge’s average draw in panel wattage (300W+ of panels for a 150W fridge), and keep the panels somewhere you can deploy them in 5 minutes. Our outage scenario walkthroughs model this for 4-, 24-, and 72-hour blackouts.

Picks by scenario

• Day trips and dorm rooms (mini-fridge): Anker SOLIX C1000 — 1,056Wh, 28.4 lb, 2,400W SurgePad. Cheap, light, plenty.
• Full-size fridge, overnight outage: Anker SOLIX C2000 Gen 2 or EcoFlow DELTA 2 Max — both ~2kWh, ~11–12 hours of fridge runtime. The DELTA 2 Max if you plan to add solar (1,000W input).
• Fridge + freezer, multi-day outage: Anker SOLIX F3000 — 3,072Wh, 3,600W continuous, 7,200W surge. The comfortable middle ground.
• Fridge + freezer + the rest of the house: EcoFlow DELTA Pro 3 or Anker SOLIX F3800 — 4kWh-class, ~22–23 hours combined runtime, and expandable. The head-to-head comparison above breaks the tie.

Want the numbers for your whole load list, not just the fridge? The /tools/rv-sizer/ runs the full arithmetic, and our general sizing guide covers capacity vs output for everything else.