How long will a portable power station run a CPAP?

Short answer: a mid-size station gets a full-size CPAP through the night with room to spare, and the small ones mostly don’t. A ResMed AirSense 11 on an EcoFlow DELTA 2 works out to about 16.5 hours on a DC adapter. Put the same machine on the EcoFlow RIVER 3 Plus and you get 4.5 hours, which is a short night at best. The travel-size ResMed AirMini is the exception. It draws so little that even that small station lasts 41.0 hours.

Where these numbers come from

Every runtime on this page is calculated, not measured. We take the station’s rated capacity, multiply it by an efficiency factor for the power path, and divide by the machine’s average draw. The efficiency factors are our assumptions, because we don’t have published figures for these stations, and they’re printed under each table. The draw figures come from the CPAP makers’ user guides and spec sheets. We haven’t run any of these machines on these stations ourselves. When we do, the table will say “measured” instead of “calculated”.

Your own nights will differ. Pressure setting, mask leak, how dry the room is and whether you use a heated tube all change the draw, and an older battery holds less than its rating. If a station only just covers your night in the table, don’t count on it covering your night in a tent.

What about the humidifier?

Here the manuals are least help. For the two ResMed AirSense machines and both Breas machines, the documents we used give one “typical” power figure, with nothing separate for humidifier on and off. Philips doesn’t publish a typical draw for the Philips DreamStation 2 at all. The only figure in its manual is the power supply rating it asks for when you humidify, so we use that as an upper bound. The ResMed AirMini figure is for its waterless HumidX setup.

So we can’t give you separate humidifier-on and humidifier-off rows yet, and we’d rather leave them out than guess. The usual advice for stretching a battery is to switch off the humidifier and the heated tube. Check what your manual says before you do, and know that how much it saves depends on the machine and your settings. Read the ResMed and Breas tables as “typical use, whatever that included”, and the DreamStation 2 table as a worst case.

AC outlet or DC adapter?

If your machine has a DC adapter, use it. The DC rows below come out a little longer under our assumptions because the station doesn’t have to run its inverter all night. We explain the difference properly in why a CPAP gets more hours from a DC adapter. The two Breas machines only show AC rows, because their user guides don’t describe a DC adapter.

Every station here has a 12V car port rated at 10 A, and all of these machines’ figures fit under that.

Runtime by machine

We picked six stations from small to large. The runtime calculator covers the rest of the stations in our data.

ResMed AirSense 11

ResMed lists one typical figure for this machine, with no humidifier split. A station around a kilowatt-hour covers a night comfortably. The two small ones don’t.

ResMed AirSense 10

By ResMed’s figures the AirSense 10 draws slightly less than the AirSense 11, so its hours come out slightly longer. In practice the two are close enough that the same station advice applies.

Philips DreamStation 2

These hours look short next to the ResMed machines, and that’s mostly down to the figure we have. It’s the power supply rating Philips asks for with humidification, which is a ceiling, not what the machine pulls on an ordinary night. Expect more hours than this table shows. We’ll replace it with a better number when we find one.

ResMed AirMini

The AirMini barely dents these batteries. Even the smallest station here covers several nights, and a mid-size one is close to overkill unless you’re also charging phones, lights and everything else off it.

Breas Z1

Breas gives a typical figure for the Z1 on its power adapter and describes no DC option, so these are AC rows only.

Breas Z2 Auto

The Z2 Auto has the same published typical figure as the Z1, so the numbers match. Again, AC only.

Which size to get

For a full-size machine like the AirSense 10, AirSense 11 or DreamStation 2, we’d skip the EcoFlow RIVER 3 Plus and Bluetti EB3A class unless you only need part of a night. Something like the EcoFlow DELTA 2, Jackery Explorer 1000 v2 or Bluetti AC180 is the sensible starting point, and it leaves margin for a cold night or a leaky mask. If you’re going off-grid for several days without a way to recharge, look at the Jackery Explorer 2000 v2 row, or plan on solar.

With an AirMini, the small stations are fine.