Best Power Station for a CPAP, Sized Night by Night

Take the published watt-hours, multiply by 0.85 for inverter losses, and divide by the CPAP draw. Our power station sizer does exactly that. At 40 W with the humidifier off, a 288 Wh unit gives about 6 hours, a 768 Wh unit about 16 hours, a 1,024 Wh unit about 22 hours and a 2,048 Wh unit about 43 hours. Plenty of machines at moderate pressure draw closer to 30 W, which stretches a 288 Wh unit to a full 8 hour night. We still size for 40 W so you are not cutting it close.

In practice the 288 Wh class is a one-night unit and the 768 Wh class covers two. The 1,024 Wh class gets you two to three nights, or one night with the humidifier running. Outages longer than that push you toward solar recharge or the 2 kWh class, which the refrigerator guide covers.

Battery percentage on the screen is not all usable. Most units shut the inverter off a little above zero, and lithium iron phosphate cells last longest when you do not drain them flat every night. Buy for the nights you need with some margin left over.

The blower in a CPAP is a small, efficient motor. The heated humidifier is a resistance heater, and heaters drain batteries. Our appliance table puts a CPAP with a heated humidifier at about 110 W with an 80 percent duty cycle, so eight hours is about 700 Wh at the mask and about 830 Wh from the battery. That is nearly three times the draw of the machine alone. It turns a 288 Wh unit into a three-hour unit.

If you can sleep without heated air for a night, switch off the humidifier and heated tube before you plug into the battery. If you can't, size for 1,024 Wh per night at minimum. The EcoFlow DELTA 3, Anker SOLIX C1000 Gen 2 and BLUETTI Elite 100 V2 all sit at that capacity.

Most CPAP makers sell a 12 V DC cord for their machines. On DC, the power station is not converting battery voltage up to 120 V and your machine's power brick is not converting it back down, and those two steps are where the 15 percent goes. Plug a DC cord into the unit's 12 V socket and a 288 Wh unit gets noticeably closer to a full night at 40 W.

The downside is the humidifier. On the DC cord it usually will not run, or runs at reduced heat, so check your machine's manual. Need the humidifier? Use the AC outlet and size up. If you can do without it, the DC cord is the cheapest capacity upgrade you can buy.

A power station with a UPS or EPS mode sits between the wall and the CPAP all the time. The CPAP runs on grid power, the battery stays topped up, and when the power drops the unit switches to battery in the time printed on the spec sheet. EcoFlow, BLUETTI and the newer Anker units advertise 10 ms, while Jackery and the original Anker C1000 advertise 20 ms. A CPAP will not notice either one, and both beat waking up at 3 a.m. to plug things in.

That is the strongest argument for the RIVER 3 Plus or the Elite 30 V2 over a unit like the Goal Zero Yeti 700, which has no advertised switchover time. Pass-through charging is how these units are meant to be used, and the manufacturers' own documentation says leaving one plugged in year-round is fine.

For one night at a time, the 288 Wh units are the right money. They are all LiFePO4 now, all under 11 lb, and close in price, so choose on UPS speed and outlet count. For two nights the BLUETTI AC70 is the standout value at 768 Wh and 1,000 W, 22.5 lb, for around $359. The math gives it about 16 hours at 40 W. For three nights or humidifier use, spend $499 or more on a 1,024 Wh unit like the BLUETTI Elite 100 V2.

None of these units can fly. FAA rules allow lithium batteries up to 100 Wh in carry-on without approval and 101 to 160 Wh with airline approval, and nothing over 160 Wh in carry-on or checked bags. The smallest unit here is 286 Wh. For air travel you need a CPAP-specific battery under 100 Wh from your machine's maker, and most of those last one night.

Road trips and camping are a different story. The 288 Wh units recharge from a car 12 V socket while you drive and from a 100 to 220 W panel at camp. The Jackery 300 v2 and Anker C300 accept 100 W of solar, the RIVER 3 Plus takes 220 W and the Elite 30 V2 takes 200 W. A few hours of real sun refills a CPAP night on any of them.

Want the fridge to stay cold too? Then stop sizing for the CPAP. A full-size fridge averages about 52 W over a day, roughly the same as the CPAP on its own, and the two together need a 1,024 Wh unit to get through 10 hours or a 2 kWh unit to get through a day. Our refrigerator guide sorts those out.

Where outages run multiple days, a bigger power station is the wrong fix. Look at a 240V home battery like the Anker SOLIX F3800 Plus, or a small dual fuel inverter generator that recharges a mid-size station. The home battery guide covers the no-install options.