Power Station & Solar Generator Runtime Calculator
Enter your battery capacity and the devices you want to run. We estimate runtime for portable power stations and solar generators using real-world inverter efficiency and the usable depth of discharge for your battery chemistry. Don't own one yet? Use the What Size Power Station Do I Need? calculator to work out what to buy.
Your power station
Your devices
Add the devices you want to run. Click a preset to add a typical wattage, or enter your own.
Estimated runtime
- Total load
- 0 W
- Usable energy
- — Wh
- Inverter loss
- —
- Load vs station max
- —
If you ran just one device
- Add devices above to see individual runtimes.
How the math works
Usable energy = Battery capacity × Depth-of-discharge × Inverter efficiency
LiFePO4 batteries can be safely discharged to ~5% without harming cycle life. Lithium-ion (NMC) batteries need to stay above ~20% for similar cycle life — so you only get 80% of rated capacity.
Inverter losses: turning DC battery power into 110/120V AC costs 12-15% of energy as heat. DC ports (USB, car socket) skip this and only lose ~5%.
Real-world tip: cold weather, partial loads (running at 10W on a unit designed for 1800W), and aged batteries can drop these numbers by another 10-20%. Plan for 80% of what this calculator shows for critical use.
Estimates only. Actual runtime varies with temperature, battery age, partial load efficiency, and inverter quality. We are not affiliated with any manufacturer mentioned on this page.
How to use the runtime calculator
Power station marketing claims like "2000Wh — runs a refrigerator for 24 hours" almost always assume best-case conditions: a brand-new battery, 25°C ambient temperature, and a refrigerator's average duty cycle (compressors are only running ~30% of the time). Real-world numbers are 30-40% lower.
This calculator gives you a defensible estimate by:
- Starting from rated capacity (Wh)
- Subtracting the unusable bottom of the battery (5% for LiFePO4, 20% for lithium-ion)
- Subtracting inverter conversion losses (15% AC, 5% DC)
- Dividing by total continuous load
Common questions
Why is my real runtime even shorter than this calculator says?
Three reasons, in order of impact: (1) your device's nameplate wattage is the peak, not the running average; (2) cold weather reduces usable capacity by 10-20%; (3) batteries older than 2 years have lost 10-15% of their original capacity.
Why is LiFePO4 better than lithium-ion for power stations?
Two reasons: deeper usable discharge (95% vs 80%) and longer cycle life (3000+ vs 500-1000 cycles). For the same rated Wh, a LiFePO4 unit gives you ~19% more usable energy and lasts 3-5× longer. Full LiFePO4 vs lithium-ion explainer →
Can I trust the manufacturer's "runs your fridge for X hours" claim?
Treat it as a marketing ceiling. The math assumes the fridge's duty cycle averages out to its rated power — true in a clean lab, optimistic in your kitchen. Use this calculator's number, then multiply by 0.8 for planning.
Power stations that match your load
The runtime number above is one input. The other is whether the station's continuous output ceiling clears your devices' instantaneous peak. Use these capacity tiers as a starting point, then cross-check against the specific model's reviews and troubleshooting notes before buying.
Compact tier · under 1,000 Wh · light loads
Suitable for: CPAP overnight, router + laptop for several hours, mini fridge for half a day. Inverter ceiling around 700-1,200 W.
Mid tier · 1,000-2,000 Wh · whole-day light loads or 6-12 h fridge
Suitable for: full-size fridge for 8-12 hours, small space heater on intermittent cycle, sump pump for an emergency window. Inverter ceiling around 1,500-2,400 W.
Large tier · 2,000 Wh and up · whole-house essentials
Suitable for: fridge + lights + comms for an overnight outage, RV daily driver, expandable battery base. Inverter ceiling around 2,000-3,600 W with X-Boost / Power Lifting on some models.
These three picks anchor the most common buyer questions; we cover other models in depth on the brand pages.