Buying guide

Best Power Station for a CPAP During Power Outages

By Jeremy Kelly · Specs last checked November 7, 2026 · Research-based, not hands-on tested

How many nights a power station can run a CPAP, worked out from ResMed's published current-draw figures. DC adapter vs. AC, why the humidifier changes everything, and four stations compared on manufacturer specs.

This is not medical advice. CPAP therapy is prescribed treatment. Before you rely on a battery, a DC adapter or a power station for your machine, check with your CPAP’s manufacturer (or your equipment supplier) and your doctor. Ask especially about turning off the humidifier or heated tube, which changes how your therapy feels. The figures below are planning estimates from manufacturer documents, not guarantees.

If you use a CPAP, an overnight outage means more than a warm fridge. It can mean a night without therapy. The good news is that a CPAP is one of the easiest medical devices to back up. With the humidifier off, it draws about as much power as a desk lamp. The catch is that the humidifier and heated tube can multiply that draw several times over, and the way you connect the machine (DC adapter or AC outlet) also matters.

This guide works through the arithmetic using the manufacturers’ own published figures, then compares four portable power stations on their spec sheets (checked November 7, 2026). We haven’t tested any of these units or any CPAP machine on them.

The numbers ResMed publishes

ResMed publishes a Battery Guide with measured current draw for its machines at different pressures, taken at 12V DC through ResMed’s own DC/DC converter. Here are the AirSense 10 rows we use below:

AirSense 10 setup (ResMed Battery Guide) Pressure Current at 12V DC Watts (amps × 12V)
SlimLine tubing, humidifier off 6 cm H₂O 0.70 A 8.4 W
SlimLine tubing, humidifier off 10 cm H₂O 0.93 A 11.2 W
SlimLine tubing, humidifier off 20 cm H₂O 1.66 A 19.9 W
SlimLine tubing + humidifier (set to 4) 10 cm H₂O 2.30 A 27.6 W
SlimLine tubing + humidifier (set to 8) 10 cm H₂O 3.66 A 43.9 W

The watts column is our multiplication (amps × 12 volts). The current figures are ResMed’s.

For the AirSense 11, ResMed’s user guide lists a typical power consumption of 56.1W and a peak of 73.2W for its 65W power supply. It doesn’t say which settings produced that typical figure, so we treat it as a cautious “humidifier and heated tube on” planning number. ResMed’s support site says its Air-series devices use “approximately the same power draw” as their S9 equivalents, and recommends turning the humidifier off when running from a battery. ResMed’s Air11 DC/DC converter accepts 12V or 24V DC input (10A / 5A) and outputs 24V at 3.75A.

For Philips DreamStation 2, the instructions for use say an 80W power supply is required to support humidification, and that the device shows a “Humidifier Off” notice on a battery pack that doesn’t support humidification. Philips sells its own DC power cord and battery adapter cable and says to use only those. We didn’t find a Philips table of typical watts, so we don’t estimate DreamStation numbers here.

If you have a different machine, look in its manual for a DC power accessory and any battery guidance, and ask the manufacturer.

The math: how many nights?

Here’s the formula we use, with every assumption labeled:

Nights = (battery Wh × 0.85) ÷ (machine watts × 8 hours)

  • 0.85 is a planning factor for usable energy after conversion losses. It’s the same factor EcoFlow and BLUETTI use in runtime formulas on some of their Amazon listings (capacity × 0.85 ÷ device watts). Real results will vary.
  • 8 hours is a sample night. Use your own sleep time.
  • Watts comes from the ResMed figures above. Your pressure, mask leak and settings change it.

Example 1: AirSense 10, 10 cm H₂O, humidifier off, ResMed DC converter

11.2 W × 8 h = 89.3 Wh per night (using the unrounded 11.16 W).

Station capacity Usable estimate (× 0.85) Nights (÷ 89.3 Wh)
245Wh (EcoFlow RIVER 3) 208 Wh about 2.3
288Wh (Anker SOLIX C300 DC) 245 Wh about 2.7
1,024Wh (Anker SOLIX C1000 Gen 2 or EcoFlow DELTA 3 Plus) 870 Wh about 9.7

For comparison, ResMed’s own table recommends a 12 amp-hour 12V battery for eight hours at this setting, a figure that includes a 50% safety margin.

Example 2: same machine, 20 cm H₂O, humidifier off

19.9 W × 8 h = 159.4 Wh per night. A 1,024Wh station: 870 ÷ 159.4 ≈ 5.5 nights. A 288Wh station: 245 ÷ 159.4 ≈ 1.5 nights.

Example 3: humidifier on (set to 4), 10 cm H₂O

27.6 W × 8 h = 220.8 Wh per night. A 1,024Wh station: 870 ÷ 220.8 ≈ 3.9 nights. A 245Wh station: 208 ÷ 220.8 ≈ 0.9 nights, so not quite one full night.

Example 4: AirSense 11 on AC at its “typical” 56.1W

If you plug the normal power brick into a station’s AC outlet, the inverter itself uses power. BLUETTI’s AC180 runtime formula assumes about 15W of self-consumption, and Jackery lists 18W standby for the Explorer 1000 v2. Using 15W as an illustrative figure:

(56.1 W + 15 W) × 8 h = 568.8 Wh per night. A 1,024Wh station: 870 ÷ 568.8 ≈ 1.5 nights. A 245Wh station: 208 ÷ 71.1 W ≈ 2.9 hours.

The takeaway: the same 1kWh station ranges from about 1.5 nights to almost 10, depending on the humidifier and whether you go DC or AC. These are our calculations on published figures, not test results.

DC adapter or AC outlet?

  • DC (via your CPAP maker’s adapter) skips the inverter, so you lose less energy. ResMed’s Battery Guide says its converter is more efficient than an inverter and shuts down to protect the battery if voltage drops too low. Plug the converter into the station’s 12V car outlet. Check that the outlet’s current rating covers the converter’s input rating. ResMed lists 10A at 12V for the Air11 converter.
  • AC (your normal power brick) is simplest and supports the humidifier on machines that need the full-size supply. It costs you the inverter overhead shown in Example 4.
  • Pass-through/UPS mode: several stations switch over automatically when the grid drops. That means your machine can stay plugged into the station every night and keep running through a sudden outage. Switch times are manufacturer claims, so test with your machine before you count on it.

Comparison table

Spec (manufacturer) Anker SOLIX C1000 Gen 2 EcoFlow DELTA 3 Plus EcoFlow RIVER 3 Anker SOLIX C300 DC
Capacity 1,024Wh 1,024Wh 245Wh 288Wh
AC output 2,000W 1,800W 300W (600W X-Boost) None (DC only)
12V car outlet 12V/10A Check the spec sheet Check the spec sheet Yes
Switchover claim <10 ms <10 ms <20 ms (Amazon listing) Not specified
Weight 24.9 lb 27.6 lb 7.8 lb 6.17 lb
Chemistry LiFePO4 LiFePO4 LiFePO4 LiFePO4
Est. nights, Example 1 ~9.7 ~9.7 ~2.3 ~2.7

“Check the spec sheet” means we didn’t confirm that value on the manufacturer pages we used for this guide.

Anker SOLIX C1000 Gen 2: best overall for multi-night outages

A 1,024Wh unit with a 12V/10A car outlet, a <10 ms switchover and 2,000W of AC. Anker names CPAP machines as an example of a device for its UPS feature. That covers a humidifier-off CPAP on DC for a week or more by our Example 1 math, with AC left over for a fridge or phones. It doesn’t support expansion batteries, and at 24.9 lb it’s a carry-to-the-bedroom unit, not a travel one.

Pros

  • 12V/10A car outlet for CPAP DC adapters
  • <10 ms switchover (claimed)
  • Enough capacity for many humidifier-off nights

Cons

  • Not expandable
  • Heavy for travel

Check Anker SOLIX C1000 Gen 2 on AmazonAffiliate link

EcoFlow DELTA 3 Plus: best if you may need to expand

The same 1,024Wh class, with a <10 ms switchover. EcoFlow says it can add extra batteries for up to 5kWh total. That matters if you want room for the humidifier on longer outages, or for other medical or household loads. It has a 5-year warranty and 27.6 lb listed weight.

Check EcoFlow DELTA 3 Plus on AmazonAffiliate link

EcoFlow RIVER 3: lightest AC option for one or two nights

At 7.8 lb with 245Wh, the RIVER 3 is easy to keep on a nightstand. By our math it covers about two humidifier-off nights on DC at 10 cm H₂O, but less than one night with the humidifier on. Its 300W AC output is plenty for a CPAP power brick. The Amazon listing claims a <20 ms switchover and 1-hour AC recharge.

Check EcoFlow RIVER 3 on AmazonAffiliate link

Anker SOLIX C300 DC: DC-only and efficient

No AC outlets, so it only makes sense if you use your CPAP maker’s DC adapter (or a CPAP that charges another way your manufacturer approves). Because there’s no inverter, there’s no AC idle drain. Anker’s US page doesn’t state a switchover time, so plan on moving the plug yourself when the power goes out.

Check Anker SOLIX C300 DC on AmazonAffiliate link

Before the next outage

  1. Ask your CPAP maker which DC cord or converter fits your exact model, and whether running without the humidifier is OK for you. Ask your doctor too.
  2. Measure a real night. Many CPAP apps and machines report pressure. A plug-in energy meter on the power brick shows actual watt-hours.
  3. Do a dry run on a normal night, with the station unplugged from the wall, and note the battery percentage in the morning.
  4. Keep the station charged. Many people leave it on pass-through charging all the time. Check the manual’s storage advice.
  5. Have a plan B: a spare charged battery, a friend’s house or a local warming/cooling center, and your supplier’s after-hours number.

Bottom line

For most CPAP users who want multi-night backup, a 1kWh-class station with a 12V car outlet is the comfortable choice. By ResMed’s published figures, it covers roughly a week or more of humidifier-off nights on DC at moderate pressure. If you only need one or two nights, a small 250–300Wh unit can do it on DC with the humidifier off. Whatever you choose, confirm the setup with your CPAP’s manufacturer and your doctor, and test it before you need it.

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