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Will it run my ___? Power station runtime calculator

Add what you need to keep running, set how many hours a day and for how many days, and get the battery size you need plus the stations from our guides that can carry it.

1 What do you need to run?
  • Full-size fridge
    Startup watts and where these numbers come from
  • Phone charging
    Startup watts and where these numbers come from
2 For how long?
Assumptions (tap to edit)
  • Usable capacity 90%, AC efficiency 85%: the figures BLUETTI's own manual uses in its runtime formula (source). Stations keep a reserve, and the inverter loses energy turning battery power into wall power.
  • DC efficiency 90%: our estimate. Running a device from a 12 V or USB-C port skips the inverter, which is why a CPAP DC cable stretches a battery.
  • Light loads: stations burn power just keeping the inverter on (often 15-20 W, per Anker in CNET's test). For small AC loads like a CPAP alone, real runtime can come in below this estimate; add a buffer or use DC.
  • Buffer: 0% by default. Add 10-20% for medical devices or long outages, and for older batteries, which hold less than when new.

The math: energy used = watts × hours × quantity × days. Battery drawn = energy ÷ efficiency (AC or DC). Rated capacity needed = battery drawn ÷ usable share × (1 + buffer). Output check: the station's continuous rating must cover everything's running watts at once, and its surge rating must cover those plus the largest single startup jump.

Stations this calculator compares (9, from our guides)
StationTierRated WhAC outputSurge
EcoFlow RIVER 3 Plusentry286 (to 858)600 W1,200 W
Anker SOLIX C300 DCentry288None (DC only)—
Anker SOLIX C1000 Gen 2mid1,0242,000 W3,000 W
Jackery Explorer 1000 v2mid1,0701,500 W3,000 W
BLUETTI FridgePowerpremium2,0161,800 W3,600 W
Jackery Explorer 2000 v2premium2,0422,200 W4,400 W
Anker SOLIX C2000 Gen 2premium2,048 (to 4,096)2,400 W4,000 W
BLUETTI Elite 200 V2premium2,073.62,600 WNot published
BLUETTI Apex 300premium2,764.8 (to 19,353.6)3,840 WNot published

Manufacturer specs, linked from each guide's research. Capacity in parentheses needs the maker's add-on battery.

An estimate, not a guarantee. Run a test at home before you depend on a station, especially for medical devices. Hardwired loads like well pumps, furnaces and 240 V appliances need an electrician and a transfer switch, not an extension cord.

Why watt-hours on the box aren't what you get

A power station's rated capacity is what the cells hold, not what reaches your fridge. The battery keeps a reserve, and turning battery power into wall power costs energy. In CNET's 2026 lab test, stations in the 1.3-2.2 kWh class kept the same full-size fridge running anywhere from about 12.6 to 29.3 hours, largely because some waste more energy just keeping their inverter on. That's why this calculator starts from your devices and works back to the rating you need, and why it uses conservative defaults you can change.

Guides that use this calculator