What size power station do you need to keep a fridge running for three days?
Short answer: 6,099 Wh of rated capacity — that's the 4 kWh+ — expandable system or generator territory. Multi-day resilience — at this scale, solar recharging starts to matter more than raw capacity.
The math, appliance by appliance
Appliance
Avg draw
Hours used
Energy
Refrigerator (full-size)
60 W
72 h
4,320 Wh
Energy needed over 72 hours
4,320 Wh
÷ 0.85 inverter efficiency
5,082 Wh
× 1.2 headroom (ageing, cold, overrun)
6,099 Wh
Recommended: 4 kWh+ — expandable system or generator territory. Output check: 150 W continuous, 900 W surge.
Fridges and freezers use their average cycling draw for energy and full compressor draw for the output check — that's why the numbers differ from the label.
The bare energy need is 5,082 Wh after inverter losses; the extra 20% covers battery ageing, cold weather, and outages running long. A smaller unit works on a good day — this size works on a bad one.
What about output watts, not just capacity?
The station must sustain 150 W continuous and survive a 900 W start-up surge. Nearly every unit in the 4 kWh+ clears both comfortably.
Could solar keep this running indefinitely?
Roughly 480 W of panels replaces a day's usage with ~4 hours of decent sun at real-world (75%) efficiency. Half that solar doubles your runtime instead of sustaining it.