Power Station Size Calculator
Pick the appliances you need to run and get a recommended power station capacity plus matching models.
Results
Enter hours for the appliances you want to run, then compute.
How it works
Add up a day of the appliances you pick, then divide by the delivery fraction (usable capacity × inverter efficiency) to get the nameplate capacity a station needs, and snap up to a standard size. This matches the runtime calculator's loss model.
delivery_fraction = usable_fraction (0.85) × inverter_efficiency (0.85) = 0.7225
required_capacity_wh = daily_wh / delivery_fraction
recommended = smallest standard tier ≥ required_capacity_wh
daily_wh- Energy your selected appliances use in a day, watt-hours.
delivery_fraction- Share of nameplate watt-hours actually delivered to AC loads — usable fraction (0.85) × inverter efficiency (0.85) ≈ 0.72.
required_capacity_wh- Nameplate capacity needed = daily_wh ÷ (usable fraction × inverter efficiency).
recommended- Nearest standard station size (500 / 1000 / 2000 / 3000 Wh) at or above the requirement.
Assumptions
- A station delivers roughly 72% of its rated watt-hours to an AC load — about 15% held by the BMS reserve, then ~15% lost in the inverter — the same figures the runtime calculator uses.
- The recommendation covers one day of the selected loads on a single charge. For multi-day off-grid autonomy, use the solar battery bank calculator.
- The station must also handle the running and peak watts shown, not just the capacity. Suggestions below screen out models whose published surge rating is under the peak; models that publish only a boost mode are kept (surge unknown) and marked, so confirm their startup rating before buying.
- Sizes snap up to the nearest common tier. A requirement above 3000 Wh points to multiple units or a home battery, not a single portable station.
FAQ
What size power station do I need?
Add up the watt-hours your appliances use in a day, divide by about 0.72 (usable capacity × inverter efficiency), and pick the next standard size up. Also confirm the station's rated watts clear your combined running load.
Should I size by capacity or by wattage?
Both. Capacity (Wh) sets how long it runs; rated output (W) sets what it can power at once. A big battery with a small inverter still can't start a 1500 W heater.
Can one power station run my whole house?
Rarely. Portable stations top out around 3–4 kWh and a few thousand watts. Whole-home backup needs a larger home battery — size that with the battery bank calculator.
Sources
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