Short answer: a portable power station’s runtime is usable Wh × inverter efficiency ÷ your load in watts. A 1,000 Wh unit can run a typical refrigerator for roughly 7-17 hours, a Wi-Fi router for days, and charge a phone dozens of times. It can’t run central air, an electric furnace or a water heater for any useful time.
Two numbers on the box
- Capacity (Wh): how much energy it holds. 1,000 Wh = 1 kWh. This sets how long things run.
- Output (W): how much power it can deliver at once, plus a short surge rating for motors starting. This sets what can run.
Usable capacity is lower than the label: LFP batteries deliver about 90-95% and the inverter loses about 10-15%, according to PowerOutage.us, which uses 0.87 inverter efficiency in its examples.
Runtime table for a 1,000 Wh station
| Device | Average draw | Approximate runtime |
|---|---|---|
| Wi-Fi router | 10 W | about 3 days |
| CPAP (no humidifier) | 30-60 W | about 15-29 hours |
| Standard refrigerator | 50-125 W average | about 7-17 hours |
| LED lights (5 × 10 W) | 50 W | about 17 hours |
| Laptop | 60 W | about 14 hours |
| Space heater on low | 750 W | about 1 hour |
Calculated as 1,000 Wh × 0.87 ÷ watts. Fridge averages from PowerOutage.us (standard models use about 1.2-1.5 kWh a day); device wattages are typical examples, so check your own labels. Medical device users should confirm runtime with the device maker.
What size do you need?
- List what you want to run and each device’s watts.
- Estimate hours per day for each.
- Add up watt-hours (watts × hours) for a day.
- Divide by 0.85 to cover losses. That’s your minimum capacity.
- Check that the output rating covers everything running at once, and that the surge rating covers your fridge or pump startup (often 2-3 times running watts).
Recharging options
- Wall outlet before a storm (keep it topped up).
- Car outlet, slowly.
- Portable solar panels, which can stretch runtime for days in sunny weather.
Power station, generator or home battery?
A power station is safe indoors, silent and affordable, but small. A portable generator gives far more energy but must run outside, at least 20 feet from the house. A home battery covers much more of the house automatically. Compare them in home battery vs generator and how long a home battery lasts.
FAQ
LFP or NMC? LFP (lithium iron phosphate) lasts more cycles and is more heat-tolerant; it’s heavier. See LFP vs NMC.
Can I plug it into my house wiring? Only through a proper transfer switch or inlet installed by an electrician. Never backfeed an outlet.