Power Stations
Rechargeable battery units with AC/DC outputs
A portable power station is a battery, an inverter, and a charge controller in one case. Capacity (watt-hours) decides how long it runs; inverter output (watts) decides what it can run at all. Those two numbers answer different questions, and buying on capacity alone is the most common sizing mistake.
How to choose
Start with output, not capacity
A 2000Wh station with a 1200W inverter will not start a typical fridge compressor, while a 700Wh unit with a 1800W inverter will — and then run flat in a few hours. Check the continuous rating against the running draw of your largest device, and the surge rating against its startup spike, which for anything with a motor or compressor can be three to seven times higher. Surge watts vs running watts covers how to measure both.
Then size the capacity
Usable capacity runs roughly 85% of the rated watt-hours after inverter losses, so a 1024Wh station delivers about 870Wh. Divide that by your device's average draw for a realistic runtime: a 60W CPAP gets about 14 hours, a full-size fridge cycling at an average 65W gets about 13. Averages matter more than peaks here — a fridge's compressor only runs part of each hour.
Battery chemistry sets the lifespan
Almost everything current uses LiFePO4, rated for 3,000–4,000 cycles to 80% capacity against roughly 500–800 for the older NMC packs. At one cycle a week that is the difference between a decade of service and about three years, and it is the spec that most changes cost-per-year. LiFePO4 vs NMC works through the math.
Match the unit to the job
For outage backup, the switchover time decides whether your equipment even notices — see using a power station as a UPS. For medical equipment, overnight draw and pure sine wave output are the constraints; our CPAP sizing guide covers that case. For a broader shortlist across capacities and budgets, start with best portable power stations.