If you use a CPAP for sleep apnea, you have probably thought about what happens when the power goes out. Maybe you have already lived through it: a thunderstorm at midnight, a transformer blowing down the street, and suddenly the gentle hum of your machine goes silent. You lie there, mask on your face, airway unassisted, doing the math on whether the power company’s “estimated restoration” is optimistic or conservative.
CPAP therapy works because it is continuous. One night without it and you are back to the apnea events, the oxygen desaturation, the fragmented sleep, and the next-day fatigue that your machine exists to prevent. For people with moderate to severe obstructive sleep apnea, an untreated night is not an inconvenience. It is a medical setback.
A portable power station can keep your CPAP running through a blackout. The good news is that CPAP machines are among the most power-station-friendly medical devices in existence. They draw very little power, they produce no startup surge worth worrying about, and they run comfortably on every power station in our database rated at 300W or above. The real question is not compatibility. It is runtime: how many nights can a given battery sustain your specific machine at your specific settings.
This guide answers that question with verified power consumption data from three CPAP models, a clear sizing framework, and practical settings that can stretch your battery life by 30 percent or more.
How Much Power Does a CPAP Actually Use?
Less than most people think. A CPAP machine is a small blower motor that pushes filtered air through a tube into your mask. At its core, it is one of the lowest-draw medical devices you can own.
The power consumption varies by model, by pressure setting, and especially by whether the heated humidifier and heated tube are running. Here are the verified figures from three models in our database:
ResMed AirSense 11 AutoSet — 56.1W running, 73.2W peak. This is ResMed’s current-generation machine, released in 2021, with a 65W power supply unit. The 56.1W figure represents typical operating draw with humidifier active. Peak draw (73.2W) occurs briefly when the humidifier heater ramps up.
ResMed AirSense 10 AutoSet — 53W running, 104W peak. The previous-generation ResMed, still widely used. The higher peak (104W) compared to the AirSense 11 reflects the older 90W power supply design. Running draw is comparable.
Fisher & Paykel SleepStyle Auto — 39W running, 76W peak. The most efficient of the three. Fisher & Paykel’s integrated humidifier design contributes to the lower draw. The SleepStyle has an AC input range of 100–115V at 1.2A typical.
What drives the wattage up or down
The blower motor itself draws relatively little power, roughly 10 to 25 watts depending on the prescribed pressure and the model. What pushes total consumption toward 40 to 56 watts is the heated humidifier. The humidifier contains a small heating element that warms water in the chamber to add moisture to the airstream, reducing dryness and irritation in the nose and throat.
The heated tube (called ClimateLineAir on ResMed machines and ThermoSmart on Fisher & Paykel) adds another 10 to 15 watts. Its job is to maintain the temperature of humidified air as it travels through the tubing, preventing condensation from pooling in the hose (a phenomenon CPAP users call “rainout”).
Higher pressure settings also increase draw. A machine set to 20 cmH2O works harder than one set to 8 cmH2O. Auto-adjusting machines (AutoSet, APAP) vary their pressure throughout the night based on detected events, so their power draw fluctuates rather than holding steady.
What Size Power Station Do You Need?
This is where the math matters. A CPAP runs for 7 to 9 hours per night. Unlike a refrigerator that cycles on and off, a CPAP draws power continuously from the moment you press start to the moment you wake up.
Nightly energy requirement
CPAP Watts × 8 hours = Watt-hours per night (raw)
Battery capacity needed
Watt-hours per night ÷ 0.70 = Minimum battery capacity (Wh)
The 0.70 derate accounts for inverter losses, battery management overhead, and real-world efficiency. The battery’s nameplate capacity is never fully available at the AC outlet.
Here is what that looks like for each CPAP model over a single 8-hour night with humidifier running:
Fisher & Paykel SleepStyle Auto (39W): 39 × 8 = 312 Wh raw. 312 ÷ 0.70 = 446 Wh battery needed.
ResMed AirSense 10 AutoSet (53W): 53 × 8 = 424 Wh raw. 424 ÷ 0.70 = 606 Wh battery needed.
ResMed AirSense 11 AutoSet (56.1W): 56.1 × 8 = 449 Wh raw. 449 ÷ 0.70 = 641 Wh battery needed.
For a single night, you need a power station with roughly 450 to 650 Wh of capacity, depending on your model and settings. For multi-night backup, multiply accordingly and add a 20 percent safety margin.
Power station recommendations by tier
| Power station | Capacity | F&P SleepStyle Auto 39W (typical) | ResMed AirSense 10 53W (typical) | ResMed AirSense 11 56.1W (typical) |
|---|---|---|---|---|
| Anker SOLIX C300 Budget | 288 Wh | 0.6 nights (5.2h) | 0.5 nights (3.8h) | 0.4 nights (3.6h) |
| Jackery Explorer 1000 v2 Recommended | 1,070 Wh | 2.4 nights (19.2h) | 1.8 nights (14.1h) | 1.7 nights (13.4h) |
| EcoFlow DELTA 2 Max Premium | 2,048 Wh | 4.6 nights (36.8h) | 3.4 nights (27.0h) | 3.2 nights (25.6h) |
Runtime = Capacity × 0.70 derate ÷ CPAP watts. Nights = runtime ÷ 8 hours. Figures reflect typical use with humidifier on. With humidifier off, expect 25–35% longer runtime.
Budget tier: Anker SOLIX C300 (288 Wh, 300W). This is the smallest station in our database that we would consider for CPAP use. With the humidifier off on a Fisher & Paykel SleepStyle (39W), it delivers roughly 5.2 hours of runtime. That is not a full night, but it covers a short outage or a situation where you disable humidification and lower pressure. It will not sustain a ResMed AirSense at full settings for a complete sleep session.
Recommended tier: Jackery Explorer 1000 v2 (1,070 Wh, 1,500W, $799). This is the sweet spot for most CPAP users. With 1,070 Wh, it delivers 2 or more full nights even with the higher-draw ResMed models. Enough capacity to ride out a typical weather-related outage without changing your CPAP settings at all.
Premium tier: EcoFlow DELTA 2 Max (2,048 Wh, 2,400W, $1,899). Four or more nights of CPAP runtime, plus enough headroom to charge your phone, run a light, and keep other small devices going. This is the station for someone who wants outage coverage measured in days, not hours, or who also needs to run other devices alongside the CPAP.
Settings That Extend Battery Runtime
If you are running your CPAP on battery during an outage, every watt you save translates directly to more sleep time. Here are the settings that have the largest impact, in order of energy savings.
Disable the heated humidifier
This is the single biggest change you can make. The humidifier heating element accounts for roughly 15 to 25 watts of your total draw, depending on the humidity level setting. Turning it off reduces power consumption by approximately 30 percent.
Without humidification, you may experience dryness in your nose and throat. This is uncomfortable but not medically dangerous for most users. If you regularly experience nosebleeds or severe nasal congestion with dry air, talk to your physician about whether this trade-off is acceptable during emergencies.
Disable the heated tube
The heated tube (ClimateLineAir or ThermoSmart) adds 10 to 15 watts. Disabling it saves roughly 10 to 15 percent of total draw. Without heated tubing, you may get condensation in the hose if the room temperature is cool, but the therapy itself is unaffected.
Use a DC power adapter instead of the AC outlet
This is the most underappreciated way to extend runtime, and the one most CPAP-on-battery guides overlook.
When you plug your CPAP into the AC outlet on a power station, the electricity follows this path: battery (DC) → inverter (converts to AC) → CPAP power supply (converts back to DC). Each conversion step loses energy. The inverter alone typically operates at 85 to 90 percent efficiency, and the CPAP’s AC-to-DC power supply loses another 5 to 10 percent.
A DC-to-DC converter plugs directly into the power station’s 12V cigarette lighter port and outputs the voltage your CPAP needs (24V for ResMed devices), bypassing the inverter entirely. ResMed sells an official DC-to-DC converter for both the AirSense 10 and AirSense 11 lines. Third-party options also exist for other models.
The efficiency gain is substantial. Instead of the 0.70 derate factor we use for AC output, DC-to-DC operation typically achieves 0.85 to 0.90 efficiency. On a 1,070 Wh battery running a ResMed AirSense 11 at 56.1W:
AC path (0.70 derate): 1,070 × 0.70 ÷ 56.1 = 13.4 hours
DC path (0.85 derate): 1,070 × 0.85 ÷ 56.1 = 16.2 hours
That is nearly 3 extra hours, close to a 20 percent improvement, from a $30 to $60 adapter.
What you need for DC-direct operation:
- A DC-to-DC converter matched to your CPAP model and voltage (24V for ResMed, check your model)
- A power station with a 12V cigarette lighter (DC) output port — most stations include one
- The correct barrel connector for your machine (ResMed AirSense 10 and 11 use different connectors)
If you can run DC, do it. AC wastes energy on two unnecessary conversions. A DC adapter is the single highest-value accessory for battery-powered CPAP use. Check which power stations work best for CPAP.
Lower pressure (only with physician guidance)
Higher pressure settings increase blower motor draw. A machine set to 20 cmH2O draws more than one set to 10 cmH2O. Some physicians may approve a temporary reduction during an emergency, but this is a clinical decision that depends on the severity of your apnea. Do not adjust your prescribed pressure without consulting your physician first.
Keep the power station at room temperature
Lithium batteries deliver less capacity in cold conditions. If you are using your CPAP during a winter storm outage in an unheated room, your power station’s effective capacity may be 10 to 20 percent lower than its nameplate rating. Keep the station near you, under blankets if necessary, to maintain its temperature.
Inverter Quality: Pure Sine Wave
All portable power stations in our database are specified by their manufacturers as producing pure sine wave AC output. This matters for CPAP machines because the CPAP’s internal power supply converts the AC power back to DC, and that conversion process works best with a clean, consistent waveform.
ResMed’s official battery guide specifies that a pure sine wave inverter is required for their devices and recommends a continuous power rating of at least 300 watts. Modified sine wave inverters can cause buzzing, overheating of the power supply, or erratic machine behavior.
Fisher & Paykel’s documentation states that their SleepStyle devices are compatible with both modified sine wave and pure sine wave inverters, provided the inverter meets the minimum 200W continuous rating. This is one of the few CPAP brands that explicitly supports modified sine wave.
Pass-Through and UPS Mode: Switchover Time Matters
Many CPAP users want to keep their power station plugged into the wall and their CPAP plugged into the station, so the battery takes over automatically if the grid fails. This is called pass-through charging, and it works — but with an important caveat.
When the grid drops, the power station needs a fraction of a second to switch from pass-through to battery output. That gap is the switchover time. If it is too long, your CPAP loses power, shuts down, and reboots. That reboot takes 10 to 15 seconds, during which your airway is unassisted. You wake up, often with a gasp.
For CPAP use, you want a switchover time under 20 milliseconds. At that speed, the CPAP’s internal capacitors bridge the gap and the machine never notices. Six power stations in our database publish UPS-grade switchover specs:
- Zendure SuperBase V4600 — 1ms switchover
- Anker SOLIX C300 — 10ms switchover
- Bluetti AC180 — 20ms switchover
- Jackery Explorer 2000 v2 — 20ms switchover
- Pecron E3600LFP — 20ms switchover
- VTOMAN Jump 1500X — UPS supported (switchover time not published)
Camping and Travel with CPAP
A portable power station is not just an emergency backup device. For CPAP users who camp, hike, or travel off-grid, it is the difference between leaving the machine at home and getting a full night of treated sleep in the backcountry.
Air travel
CPAP machines are classified as medical devices by the FAA and TSA. The ResMed AirSense 11 carries an FAA compliance label on the bottom of the unit. You can bring your CPAP as a carry-on in addition to your regular luggage allowance, and it does not count against your bag limit. Lithium battery power stations are subject to airline restrictions (typically 100 Wh per battery without approval, up to 160 Wh with airline approval), so check your carrier’s policy before flying with a large power station. Smaller units like the Anker SOLIX C300 (288 Wh) exceed the 160 Wh limit and cannot be carried on commercial flights. For air travel, purpose-built CPAP batteries under 100 Wh are the practical option.
Solar recharging for extended trips
For multi-day camping, a solar panel can recharge your power station during the day while you sleep on battery at night. The math is straightforward: a 100W solar panel in good sun conditions (roughly 5 peak sun hours per day) produces approximately 350 to 400 Wh per day after losses. That is enough to replenish a single night of CPAP use on most models, creating a sustainable daily cycle. Use our solar charge time estimator to calculate recharge times for your specific setup.
A 288 Wh station paired with a 100W panel reaches full charge in roughly 4 to 5 hours of direct sunlight. A 1,070 Wh station needs 200 to 300W of panels to fully recharge in a single day, or you can accept a partial recharge and size your battery to carry the deficit.
The DC adapter advantage for camping
The DC-to-DC converter discussed earlier is even more valuable for camping than for home outage backup. Every watt-hour saved is a watt-hour you do not need to replace with solar. Running DC-direct instead of through the inverter effectively gives you 20 percent more capacity from the same battery, which can mean the difference between needing a 100W panel and needing a 200W panel.
Our Compatibility Results
Every CPAP machine in our database receives a SAFE verdict against every power station rated at 300W continuous or above. All 33 power stations in our database clear the surge check, the running watts check, and the runtime check with margin.
This is not surprising. A CPAP machine drawing 39 to 56 watts with a peak of 73 to 104 watts is among the easiest loads a portable power station can handle. Even the smallest station in our database (the Anker SOLIX C300 at 300W continuous, 300W peak) has roughly 3 to 5 times the continuous capacity and 3 to 8 times the surge capacity needed. See our CPAP compatibility results for a detailed example.
The compatibility question for CPAP is fully settled. The sizing question is where the real decision lives: how many nights do you need, with what settings, and are you willing to use a DC adapter to stretch the runtime. Our compatibility calculator can help you compare options.
Frequently Asked Questions
Can I use a modified sine wave inverter with my CPAP?
ResMed explicitly requires a pure sine wave inverter for AirSense devices. Fisher & Paykel states that their SleepStyle is compatible with modified sine wave. If you are using any standalone inverter (not a dedicated power station), verify the waveform type before connecting your CPAP. All portable power stations in our database output pure sine wave, so this concern only applies to DIY setups with standalone inverters and car batteries.
Will my CPAP work on a car battery with an inverter?
Technically, yes. A 12V car battery with a pure sine wave inverter (minimum 300W continuous for ResMed, 200W for Fisher & Paykel) can run a CPAP. However, there are practical problems. A car battery is designed for short, high-current bursts (starting the engine), not sustained low-draw overnight use. Deep-discharging a starter battery damages it and may leave you unable to start your car. If you go this route, use a deep-cycle marine battery, not your car’s starter battery. A dedicated portable power station is a simpler, safer, and more reliable solution.
How many nights will my power station last?
Night count formula
Nights = (Battery Wh × 0.70) ÷ CPAP watts ÷ 8
For AC power (plugged into the wall outlet of the power station), use 0.70. If you are using a DC-to-DC adapter, replace 0.70 with 0.85. The CPAP watts figure should reflect your actual settings: full draw with humidifier on, or reduced draw with humidifier off.
Does my CPAP have a battery inside?
No. Standard CPAP machines (ResMed AirSense 10, AirSense 11, Fisher & Paykel SleepStyle) do not contain internal batteries. They require an external power source at all times during operation. Some travel-specific CPAP models exist with integrated batteries (such as the ResMed AirMini, which can use an optional battery), but these are separate products with different power characteristics than the bedside machines covered in this guide.
Should I keep my power station plugged in all the time?
Yes, if your station has UPS-grade switchover (under 20ms). See the pass-through and UPS section above for the six stations in our database with verified switchover specs. If your station does not publish a switchover time, keep it charged and switch to battery manually before bed during outage-prone weather.
Sources: ResMed AirSense 10 power consumption from ResMed Battery Guide (53W typical, 104W peak, pure sine wave inverter required, minimum 300W continuous). ResMed AirSense 11 power supply rated at 65W per ResMed product specifications; operating draw 56.1W typical, 73.2W peak from GeneratorChecker device database. Fisher & Paykel SleepStyle Auto specifications: AC input 100–115V, 1.2A typical per F&P product documentation; compatible with modified sine wave inverters per F&P Portable Power Guide. Jackery Explorer 1000 v2: 1,070 Wh, 1,500W. EcoFlow DELTA 2 Max: 2,048 Wh, 2,400W. Anker SOLIX C300: 288 Wh, 300W. All power station specifications from manufacturer product pages. FAA CPAP compliance per ResMed AirSense 11 unit labeling.