A CPAP uses much less than you think
Most CPAP machines draw 30–60W in normal use. Over an eight-hour night that is roughly 250–500Wh — well within even a modest battery. People routinely over-buy for this.
The heated humidifier is the whole story. Running it can double or triple consumption. Switching it off — or using a heat-and-moisture exchanger instead — is the single biggest change you can make to runtime.
Nights per charge
| Station | Capacity | No humidifier | With humidifier |
|---|---|---|---|
| EcoFlow Delta 2 | 1,024Wh | 2–3 nights | ~1 night |
 Bluetti AC200L | 2,048Wh | 4–6 nights | 2 nights |
 Bluetti Apex 300 | 2,764Wh | 6–8 nights | 2–3 nights |
Two things worth doing
- Use the DC output if your machine supports it. Going battery → inverter → AC adapter → DC wastes energy at every step. A DC cord can cut consumption noticeably.
- Turn off the humidifier for battery nights. It is the difference between one night and three.
This is general information, not medical advice. If your CPAP therapy is medically necessary, do not rely solely on a battery for backup — talk to your equipment supplier about what they recommend.
What to buy
For occasional camping, 500–1,000Wh is plenty. For outage backup where you also want a fridge running, size for the fridge instead — it dwarfs the CPAP. See power station for a refrigerator or use the picker.