Running a CPAP off-grid: the field guide
A CPAP draws only ~9 W with the heated humidifier off, but ~56 W with it on — a 6× swing that decides how many nights any power station covers.
Sizing a power station for a CPAP isn't about hours, it's about nights — and the one setting that changes everything is the heated humidifier. Here's how to think about it, whether you're prepping for outages or heading off-grid.
The humidifier is the whole decision
A CPAP’s blower motor is tiny; the heated humidifier is what draws real power. Our sourced figures show the gap — and it’s the number that sets how many nights a station lasts.
| Setting | Draw | Energy per night | Source |
|---|---|---|---|
| CPAP (humidifier off) | 9 W | ~72 Wh | 2026-07-06 |
| CPAP (heated humidifier on) | 56 W | ~448 Wh | 2026-07-06 |
Nights per charge, on real stations
Nights per charge is usable watt-hours divided by the energy your CPAP uses each night. Using our published AC efficiency (85%) and an 8-hour night, here’s the swing the humidifier makes across a few well-scored units.
| Model | Usable capacity | Humidifier off | Humidifier on |
|---|---|---|---|
| Bluetti AC70 | 768 Wh | ~9.1 nights | ~1.5 nights |
| EcoFlow DELTA 3 | 1,024 Wh | ~12.1 nights | ~1.9 nights |
| Anker SOLIX C1000 Gen 2 | 1,024 Wh | ~12.1 nights | ~1.9 nights |
| Jackery Explorer 1000 v2 | 1,070 Wh | ~12.6 nights | ~2.0 nights |
Running on the 12 V DC output instead of AC squeezes out a bit more, and your real machine and pressure settings shift these numbers. The CPAP runtime tool gives the exact nights-per-charge for your setup.
Choosing a bedside-safe unit
For a unit that sits by your bed all night, chemistry and noise matter as much as capacity. LFP runs cool and safe; a quiet or fanless-at-low-load design won’t wake you.
Good bedside CPAP unit
- LFP chemistry — cooler, safer for indoor overnight use
- 12 V DC output with your machine's DC cord
- Quiet or fanless at low load (a CPAP barely loads it)
- Enough usable capacity for your nights, plus solar to recharge
Think twice
- NMC chemistry for a sealed bedroom (runs hotter)
- A loud always-on cooling fan next to your pillow
- Sub-500 Wh if you rely on the heated humidifier
- No DC output, forcing the less-efficient AC path
Every unit above appears on our best power stations for CPAP ranking, which sets a usable-capacity floor of ~900 Wh — about two heated-humidifier nights — and orders by the BatteryRank score.
Frequently asked questions
- How many nights will a power station run a CPAP?
- It depends almost entirely on the heated humidifier. With it off, a CPAP draws only ~9 W — about 70 Wh a night — so even a 1 kWh station covers a week or more. With the heated humidifier on, draw jumps to ~56 W (~450 Wh a night), and the same 1 kWh station covers closer to two nights. Turning the humidifier off, or using a heated hose on a low setting, is the single biggest lever on runtime.
- Should I run my CPAP off DC or AC to save power?
- DC, if your machine supports it. Running the CPAP from the station's 12 V DC output (with the manufacturer's DC cord) skips the inverter's AC conversion loss, so you get modestly more nights from the same battery. Many ResMed and Philips machines sell a DC adapter for exactly this reason. If you must use the AC outlet, expect a little less runtime.
- Is a power station safe to run a CPAP overnight by my bed?
- Generally yes. Prefer a unit with LFP (lithium iron phosphate) chemistry — it runs cooler and is far less prone to thermal issues than NMC, which is why it's favored for bedside and indoor use. A quiet or fanless-at-low-load unit is also worth seeking so it doesn't disturb sleep. See our LFP vs NMC guide for the chemistry comparison.
- Will a CPAP's inverter draw drain the battery even without the humidifier?
- A little. An AC inverter uses some idle power just being on, so at very low loads like a humidifier-off CPAP, the conversion overhead is proportionally larger. Running on DC avoids most of this. Either way the humidifier, not the inverter, dominates the math.
- What size power station is best for CPAP camping?
- For humidifier-off use, a compact 500–800 Wh unit covers several nights and stays light enough to pack. If you need the heated humidifier, size up to ~1 kWh or more for two-plus nights, or plan to recharge with solar between nights. Get the exact nights-per-charge for your machine from our CPAP runtime tool.