Power Station Runtime Calculator
Estimate how long your portable power station will run an appliance using battery capacity, real-world inverter efficiency and usable energy—not an ideal laboratory number.
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Tip: use the appliance's running watts here. Motor-driven devices may also need enough inverter headroom for startup surge.
- Usable energy
- 765 Wh
- Total draw
- 105 W
- Load vs inverter
- 10%
Planning estimate, not a guarantee. Temperature, battery age, power factor and device cycling can change real runtime.
How this runtime estimate works
The calculator multiplies the battery’s rated watt-hours by the usable-capacity setting and inverter efficiency. It then divides that usable energy by the appliance load plus the power station’s own idle draw.
1. Usable energy
Capacity × usable percentage × efficiency
2. Total draw
Appliance running watts + station idle draw
3. Runtime
Usable watt-hours ÷ total watts
Example: A 1,000 Wh power station at 90% usable capacity and 85% inverter efficiency provides about 765 Wh. With a 100 W appliance and 5 W idle draw, the estimate is about 7.29 hours.
Power station runtime questions
Why is real runtime lower than battery capacity ÷ watts?
Power conversion creates heat and the inverter consumes energy. Battery-management systems also reserve some capacity, so the full label rating is rarely available at the outlet.
Should I enter running watts or startup watts?
Enter normal running watts for runtime. Then compare the appliance’s startup or surge requirement with the power station’s surge rating to make sure it can start safely.
How do solar panels affect the result?
This calculator shows battery-only runtime. Stable solar input can extend operation, but actual solar production changes with weather, panel angle, shading and charge-controller limits.
Is this calculator tied to a specific power station brand?
No. PowerRuntime is brand-neutral. You can use the watt-hour capacity and inverter rating from any manufacturer’s specifications.
Need the appliance wattage first?
Use practical running-watt and startup-surge ranges from our appliance library.