During a power outage or a camping trip, the question every CPAP user asks is simple: will my machine last the night? With a portable power station, the answer is usually yes, and you can work out exactly how long with one formula.
This guide is about power, not therapy. Always follow your doctor’s and equipment provider’s advice for your CPAP settings.
Skip the math: use our CPAP battery calculator to get your hours and nights instantly.
The formula
Runtime (hours) = power station capacity (Wh) × 0.85 ÷ CPAP power draw (W)
- Capacity is printed on every power station, in watt-hours (Wh).
- 0.85 accounts for the energy lost when the power station converts battery power to AC for your machine’s adapter. If you run from a DC cable instead, you can use about 0.9–0.95.
- Power draw is what your CPAP actually uses, in watts. It varies a lot with your pressure setting and, above all, with the humidifier.
How much power does a CPAP use?
The wattage printed on your CPAP’s power supply is the maximum, not what it uses all night. Real consumption depends on the model and your settings. As a rough guide:
- Without humidifier: often in the range of 30–60 W
- With heated humidifier: commonly 60–90 W or more
- With heated humidifier and heated tubing: the highest draw
The most accurate way to know is to measure it: plug the CPAP into a plug-in energy meter at home for one night, then divide the watt-hours used by the hours you slept. Many power stations also show the live wattage on their screen.
Runtime chart
Estimated hours of use when running through the power station’s AC outlet:
| Power station capacity | CPAP at 30 W | CPAP at 60 W | CPAP at 90 W |
|---|---|---|---|
| 300 Wh | ~8.5 h | ~4.3 h | ~2.8 h |
| 500 Wh | ~14 h | ~7 h | ~4.7 h |
| 1,000 Wh | ~28 h | ~14 h | ~9.4 h |
| 2,000 Wh | ~57 h | ~28 h | ~19 h |
Divide by your usual sleep (say 8 hours) to get the number of nights. A 1,000 Wh unit running a CPAP at 60 W, for example, covers about 14 hours, or close to two nights.
How to get more nights out of the same battery
- Use a DC cord if your CPAP supports one. Skipping the AC conversion is the easiest win.
- Lower or turn off the humidifier, if your provider agrees. It is usually the biggest consumer.
- Turn off the heated tube or use a hose cover instead.
- Recharge during the day from solar panels or a car outlet, so you start each night full.
- Keep the power station warm. Batteries deliver less in the cold; keep it inside the tent or the house.
Which power station to choose
For a CPAP, look for:
- Enough capacity for your nights: use the chart above with your real wattage.
- A pure sine wave inverter (standard on reputable power stations), which is safe for medical device adapters.
- LiFePO4 battery chemistry, which lasts thousands of charge cycles.
- A DC output that matches your CPAP’s DC cord, if you use one.
- Solar charging input, for outages longer than a night or two.
Compare power stations for CPAP backup. Look for a model with the capacity you calculated, a pure sine wave inverter and a LiFePO4 battery. Our picks are in the best power station for CPAP guide.
The bottom line
Most CPAP users can get through one or more nights on a mid-size portable power station. Measure your machine’s real draw, apply the formula, and add a margin for cold weather and humidifier use. If you are preparing for outages, pair the power station with a solar panel so you are not limited to what’s in the battery.
Frequently asked questions
- Can a portable power station run a CPAP all night?
- Yes. Most CPAP machines draw far less power than a power station can deliver. Even a compact unit of around 300 Wh can usually cover a full night without the humidifier. With the heated humidifier on, plan for a larger unit or expect fewer hours.
- Should I turn off the CPAP humidifier on battery power?
- The heated humidifier and heated tubing are usually the biggest power draws, often doubling or tripling consumption. Turning them off stretches runtime a lot, but talk to your doctor or equipment provider before changing your therapy settings.
- Is it better to use the DC port or the AC outlet?
- If your CPAP maker offers a DC power cord or converter for your model, running from the power station's DC output avoids the losses of converting to AC and back, which can add noticeable runtime.
- What size power station do I need for a CPAP?
- For one or two nights during an outage or a camping trip, 500 to 1,000 Wh covers most users comfortably, even with some humidifier use. Use the formula in this guide with your machine's real power draw to confirm.