How long will a power station run a CPAP?
A 1,000Wh power station runs a typical CPAP for about 98 hours — roughly 12 nights — with the humidifier off. Switch the heated humidifier on and the same battery gives about 20 hours, or 2.5 nights. The humidifier, not the machine, is what drains the battery.
Power-draw figures for the machines below are provisional estimates, not yet our own meter readings. See how we test.
That gap between 12 nights and 2.5 nights is the whole answer, and it is why most advice on this is useless. Retailers quote battery capacity in watt-hours and CPAP runtime in vague "nights", without ever saying whether the humidifier was running. The humidifier is a heating element. It draws roughly five times what the blower does.
Below is the runtime for common machines against common batteries, with the assumptions stated. Every figure comes from one shared calculation so nothing on this site contradicts anything else on it.
The maths, so you can check it
Runtime is capacity divided by draw, minus losses. Two losses matter and both are easy to forget.
Usable capacity. A battery rated 1,000Wh does not deliver 1,000Wh. Cells are not run to absolute zero, so plan on about 90% being usable.
Inverter loss. Running your machine from the AC outlet means the battery converts DC to AC and your CPAP's brick converts it back to DC. That round trip costs roughly 10–15%. Running the machine on DC skips it — which is a bigger deal than it sounds, and has its own guide.
So: hours = (capacity × 0.9 × 0.85) ÷ watts on AC, using 0.95 instead of 0.85 on DC.
Runtime by battery size — humidifier off
A ResMed AirSense 11 at around 10 cmH₂O draws roughly 8W with the humidifier off. At that draw, capacity goes a long way:
| Battery | Capacity | Runtime | Nights (8h) |
|---|---|---|---|
| EcoFlow River 3 | 245Wh | 23 hours | 2.9 |
| Jackery Explorer 300 | 293Wh | 28 hours | 3.5 |
| Anker SOLIX C300 | 288Wh | 28 hours | 3.4 |
| Bluetti Elite 100 V2 | 1,024Wh | 98 hours | 12.2 |
| EcoFlow Delta 2 | 1,024Wh | 98 hours | 12.2 |
Runtime with the humidifier on
Switch the heated humidifier on and the same machine draws around 40W. Every figure above collapses by a factor of five:
| Battery | Capacity | Runtime | Nights (8h) |
|---|---|---|---|
| EcoFlow River 3 | 245Wh | 4.7 hours | 0.6 |
| Jackery Explorer 300 | 293Wh | 5.6 hours | 0.7 |
| Anker SOLIX C300 | 288Wh | 5.5 hours | 0.7 |
| Bluetti Elite 100 V2 | 1,024Wh | 19.6 hours | 2.4 |
| EcoFlow Delta 2 | 1,024Wh | 19.6 hours | 2.4 |
What this means in practice
For a power outage of a night or two, a 300Wh station is enough only if you turn the humidifier off. Most people find dry air tolerable for a couple of nights; it is a far better trade than no therapy.
For camping or an outage lasting several days, 1,000Wh is the sensible tier — about 12 nights without humidification, or 2.5 with. That is also the point where the battery becomes useful for phones, lights and a CPAP together.
If you must have humidification every night, budget on watt-hours rather than nights: roughly 320Wh per night of heated humidification, before losses.
BiPAP and travel machines differ
Bilevel machines cycle between two pressures and draw more — an AirCurve 10 runs closer to 12W without humidification, so subtract about a third from the figures above.
Travel machines go the other way. A ResMed AirMini uses waterless humidification, so there is no heating element at all: about 6W all night, humidified or not. On a 1,000Wh station that is over 130 hours.
- Can I run a CPAP on a 300Wh power station all night?
- Yes, with the humidifier off — a 300Wh station gives roughly 28 hours on a typical CPAP, so three nights. With heated humidification on, it gives about 5.5 hours, which is less than a full night.
- Does turning off the humidifier really matter that much?
- Yes. The blower draws around 8W; the humidifier's heating element pushes total draw to about 40W. Turning it off multiplies your runtime by roughly five.
- What size power station do I need for three nights?
- About 250Wh with the humidifier off, or roughly 1,000Wh with it on, assuming eight hours a night at typical pressure.
- Is it safe to run a CPAP from a power station?
- Running a CPAP from a pure sine wave power station is electrically fine and widely done. Check that your unit specifies pure sine wave rather than modified sine wave, and confirm the machine's power requirements in its manual.
Keep reading
Keep reading
- Does the CPAP humidifier drain the battery?
Yes — dramatically.
- What size power station do you need for a CPAP?
For dry therapy, budget roughly 65Wh per night — so about 200Wh covers three nights.
- Should you run a CPAP on DC or AC from a battery?
Run it on DC if your machine supports it.
- Does a CPAP need a pure sine wave inverter?
Use pure sine wave.