Free CPAP tool
CPAP Power Station and Solar Sizing for Camping
Enter your machine's average draw, hours per night, number of nights, how the machine connects, and a safety reserve. You get the watt-hours your power station should hold. Add a solar panel's rating and your expected sun hours to see whether daily charging covers a night.
Formula
Energy per night = watts x hours. Battery energy per night = that / efficiency. Capacity needed = battery energy per night x nights x (1 + reserve). Solar recharge per day = panel watts x peak sun hours x derate. Daily balance = solar recharge minus one night's battery use.
The defaults are planning examples, not measurements: 12 W is a humidifier-off example, 85% allows for an AC inverter, 20% reserve covers cold nights and battery aging, and 75% derate allows for panel angle, heat and clouds. Use your own machine's measured draw; with the humidifier on it can be several times higher (ResMed lists 56.1 W typical for the AirSense 11 power supply).
Worked example
12 W x 8 h = 96 Wh per night. Divided by 0.85 = 112.94 Wh from the battery. For 3 nights with a 20% reserve: 112.94 x 3 x 1.2 = 406.59 Wh, so choose a station of at least about 410 Wh usable. A 100 W panel with 4 peak sun hours at 75% gives 100 x 4 x 0.75 = 300 Wh a day, and the daily balance is 300 minus 112.94 = 187.06 Wh, so the panel can keep up in good sun.
Assumptions and limits
- Station capacity labels are often total, not usable; check the usable figure or add reserve.
- Peak sun hours vary by place and season; look up your location rather than relying on the default.
- Cold weather reduces battery capacity, and many stations charge slowly below freezing.
- Running the humidifier off battery is often the difference between one night and several.
Supplies that can help
A battery pack that runs a CPAP machine without mains power, for camping, power outages or long flights.
A cord or converter that runs a CPAP from a 12 V or 24 V DC source, such as a car outlet, RV or deep cycle …
A heat and moisture exchanger (HME) that captures warmth and moisture from your breath and returns it on the next breath, used mostly with travel CPAPs …
A padded bag that protects the machine, mask, tubing and power supply in transit.
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Frequently asked questions
What size power station do I need for CPAP camping?
Multiply your machine's average watts by hours per night, divide by efficiency, multiply by nights, then add a reserve. At 12 W for 3 nights through an inverter, about 410 Wh. With the humidifier on, plan for much more or use a heat-and-moisture exchanger instead.
Can a solar panel run my CPAP overnight?
No, solar charges the power station during the day and the station runs the machine at night. The question is whether a day of sun refills one night of use, which is what the daily balance output shows.
Is it better to plug my CPAP into the AC outlet or the DC port?
The DC port with the maker's DC cable or converter avoids inverter losses and usually runs longer. Only use DC accessories your machine's maker approves.
Sources
Last reviewed October 11, 2026. How we research · Report an error