Solar
Portable Power Station Calculator
Required portable capacity equals load energy divided by usable output efficiency. Runtime and recharge estimates separately apply the candidate capacity and charging efficiency.
Estimate portable power-station capacity, runtime, and recharge time from an AC load, daily hours, trip length, usable efficiency, and charging input.
Calculated result
Portable-power estimate
Calculating…
Calculated locally in your browser
Planning math only. Verify equipment specifications and installation requirements separately.
Equipment planning
Components that meet these requirements
The specification is calculated from the result above. Product links appear only when an enabled catalog entry meets every displayed requirement.
Disclosure: Power Totals may earn a commission from qualifying purchases through the partner links below, at no additional cost to you.
Calculate above to generate a parts requirement.
Cable, fuse, breaker, disconnect, mounting, grounding, and code requirements need separate equipment and installation review.
Data provenance: NLR PVWatts v8 grid awaiting its first private-key refresh; the visible peak-sun-hours fallback is active. EIA residential state averages updated 2026-08-13. ZIP centroids use the 2025 Census Gazetteer. No ZIP or calculator input is sent to those sources. Read the solar data provenance and limitations.
What this calculator returns
Compare required capacity, continuous output, surge rating, port limits, and charging-source limits with the actual station documentation.
Formula and variables
The calculation runs entirely in your browser. Static formulas, definitions, examples, and tables remain readable without JavaScript.
Required Wh = load watts × hours/day × days / usable efficiency; runtime = station Wh × usable efficiency / load watts; recharge time = station Wh / (input watts × recharge efficiency).
- W
- Average real power in watts.
- h
- Operating or charging time in hours.
- kWh
- Accumulated electrical energy in kilowatt-hours.
- rate
- User-entered electricity price per kilowatt-hour.
- η
- User-entered efficiency expressed as a decimal or percentage.
Capacity is the station nameplate watt-hours. Both efficiency factors are visible user assumptions.
Worked example
| Input | Value |
|---|---|
| Continuous load | 100 W |
| Use per day | 5 h |
| Days between charges | 2 days |
| Candidate station capacity | 1000 Wh |
A 100 W load for five hours daily over two days needs about 1,176 Wh at 85% usable efficiency. A 1,000 Wh station runs that load about 8.5 hours.
Reference table
| Load example | Planning watts | Energy for 4 hours | Important check |
|---|---|---|---|
| Laptop on 120 V output | 65 W | 260 Wh | Charger input rating |
| CPAP example on 120 V output | 40 W | 160 Wh | Do not use this page for life-safety planning |
| Portable refrigerator | 60 W average example | 240 Wh | Duty cycle and startup |
| 240 V U.S. load | Use measured watts | W × h | Most portable stations do not supply 240 V; verify the exact model |
Frequently asked questions
How many watt-hours should a power station have?
Multiply load watts by required operating hours and days, then divide by the entered usable-efficiency fraction.
Why can recharge time be longer than Wh divided by charger watts?
The calculator applies the entered recharge efficiency; real charging can also taper or be limited by the station.
Why is nameplate Wh not fully usable?
Conversion losses, reserve limits, standby use, and operating conditions reduce energy available at an output port.
Assumptions and limitations
- Planning energy math only; battery aging, low-temperature limits, standby draw, inverter surge, and charge taper vary by model.
- Verify every output port, charger, cable, and environment limit.
- Do not use the runtime estimate for medical or life-safety planning.
Method and sources
Review the solar data sources, calculation methodology, and electrical formulas for the references most relevant to this calculation. The broader technical sources index records source scope and verification. Last reviewed .