Size a power station by energy (watt-hours) and output (watts). Runtime in hours is roughly watt-hours × 0.85 ÷ device watts, allowing for inverter losses. A 1,000 Wh unit runs a 50-watt CPAP for about 17 hours or a full-size fridge for several hours of real use. LiFePO4 batteries last far more cycles than NMC. Solar panels recharge during long outages.
Power stations are silent battery packs with outlets. They are safe indoors, which makes them the go-to backup for apartments and medical devices.
Two numbers
| Spec | Measures | Decides |
|---|---|---|
| Watt-hours (Wh) | Stored energy | How long it runs |
| Continuous watts | Inverter output | What it can power at once |
| Surge watts | Short peak output | Starting motors such as fridges |
Runtime math
Runtime (hours) ≈ Wh × 0.85 ÷ device watts. The 0.85 allows for inverter and conversion losses.
| Device | Typical watts | Hours on 500 Wh | Hours on 1,000 Wh |
|---|---|---|---|
| Phone charging | 10 to 20 | 20+ charges | 40+ charges |
| Wi-Fi router | 10 to 20 | 21 to 42 | 42 to 85 |
| CPAP without humidifier | 30 to 60 | 7 to 14 | 14 to 28 |
| LED lamp | 10 | 42 | 85 |
| Full-size fridge (average while cycling) | 100 to 200 | 2 to 4 | 4 to 8 |
Check your own devices’ labels; these are typical ranges.
Battery chemistry
| LiFePO4 | NMC | |
|---|---|---|
| Typical cycle life | Thousands | Hundreds to about a thousand |
| Weight | Heavier | Lighter |
| Heat tolerance | Better | Lower |
Recharging
Wall charging is fastest. For outages longer than a day, solar panels matched to the station’s input limit keep it going. Car charging is slow but useful.
Bigger needs
Related: How to Stay Warm Without Power in a Winter Outage.
To power circuits in the house, see whole-home batteries and generators on our sister site HomeSystemsTested. For outage planning, read the power outage checklist. Browse power, light and comms.
Common questions
What size power station do I need for a fridge?
Usually 1,000 to 2,000 Wh with at least 1,000 W continuous and good surge capacity for the compressor start. Check your fridge's daily kWh.
How long will a power station run a CPAP?
Roughly watt-hours × 0.85 ÷ CPAP watts. Turning off the heated humidifier and using DC power extends runtime a lot.
Is LiFePO4 better than NMC?
LiFePO4 typically lasts thousands of cycles and is more heat-tolerant. NMC is lighter for the same capacity.
Can I run a power station indoors?
Yes. Unlike generators, power stations produce no exhaust, so they are safe indoors.