CPAP Battery Calculator — How Long Will My Battery Last?

Enter Your CPAP Setup

Select your machine type and settings. We'll calculate what battery size you need to get through each night — and how many nights a given battery will last.

1. Machine type

2. Pressure setting (cm H₂O) Check your prescription or machine display. If unsure, enter 10 — a common midrange setting.

3. Heated humidifier?

Yes — humidifier onAdds 20–40W to power draw No humidifier / turned offSignificantly extends battery life

4. Hours of use per night

5. How many nights of backup do you need?

I have read and agree to the Terms of Use, including the calculator disclaimer and the binding arbitration and class-action waiver. I understand that all results are planning estimates only, are not medical or safety determinations, and that I use them at my own risk.

Your CPAP Battery Requirements

Recommendations:

Planning estimate only. Actual power consumption varies by machine model, mask type, pressure fluctuations, altitude, and humidifier settings. These calculations are estimates based on typical wattage ranges for each machine class. Consult your CPAP equipment supplier or respiratory therapist for precise specifications for your machine. Always test your battery system before an actual emergency.

Does Your CPAP Already Have a Battery?

Before you buy anything, find out what you already own. Some CPAP makers sell a battery built for their own machine, and a few sell it in a bundle with the machine. If yours came with one, the night is already covered, and the calculator above only has to tell you whether that battery lasts as long as the outage.

Most bedside machines have no battery inside. The machines most people sleep with, such as the ResMed AirSense 10 and AirSense 11, run from the wall. The battery is an extra you buy separately. ResMed made its own Power Station II for the AirSense 10. The AirSense 11 is usually paired with a battery from another company, such as the Medistrom Pilot-24 Lite, using a cable kit made for that machine.

Travel machines are built around batteries, but the battery is still usually extra. The Transcend Micro, the Breas Z1 and Z2, the ResMed AirMini and the Philips DreamStation Go all have batteries made for them. Most of these are sold separately. Some come bundled with the machine: Transcend sells a Micro package that includes its PowerAway battery, which the company rates at up to 17.5 hours.

If you have a Philips machine: Philips stopped selling new CPAP machines in the United States in January 2024 under an agreement with federal regulators. It still services the machines already in people's homes and still sells accessories and parts for them.

How to find out in five minutes

Look in the box and the carrying case for a separate battery or a pack that clips onto the machine.
Look on the back of the machine and in the manual for the words "DC input" or "battery." DC input means it can run straight from a battery with the right cable. That skips the power-wasting inverter.
Call the supplier who gave you the machine. They can tell you in one call whether your model has a battery made for it, and what it costs.
Expect to pay for it yourself. Insurance often treats a CPAP battery as a convenience rather than a medical need. See the Medicare question below.

If you have one, test it before you need it

Charge it fully and run one ordinary night on it with the power still on. Leave the humidifier off, because the heater is usually the biggest power draw. Next morning, check how much charge is left. That tells you what one night really costs your machine.

A CPAP with its own battery also makes the rest of the house easier to plan for. The home backup no longer has to carry the machine overnight. It only has to recharge the CPAP battery during the day while the generator is running.

If you are putting together that kind of home backup on a tight budget, the poor man's battery backup walks through it: a generator by day, a few batteries by night, and nothing wired into the house.

Common Questions

A senior woman sleeping peacefully while her oxygen concentrator runs from a battery power station on the nightstand — She is asleep, which is the only measure of whether any of this worked. **A battery station does not have to run a house — it has to run one machine from bedtime until morning**, and that is a far smaller and far cheaper problem than the one people imagine.

What happens if I skip CPAP during a power outage?

For most people with sleep apnea, one or two nights without CPAP causes disrupted sleep and increased apnea events, leading to fatigue and elevated blood pressure the next day. For people with severe sleep apnea or related cardiovascular conditions, extended periods without therapy can increase risk of cardiac arrhythmia or other events. Talk to your doctor about your specific risk level.

Can I use my car battery to run my CPAP?

Yes, with the right equipment. Most CPAP machines can run from a 12V DC car adapter (check your machine's specifications). A dedicated portable power station (like a Jackery or Goal Zero) is safer and more reliable than running directly from your car battery. Running a car continuously to power a CPAP is dangerous due to carbon monoxide risk — never run your car in a garage.

What size battery bank do I need for my CPAP?

A basic CPAP without humidifier at mid-range pressure uses approximately 30–45 watts per hour. For 8 hours of use, that is 240–360 watt-hours. A 288Wh battery (such as the Jackery 300 or similar) provides approximately one night. For multiple nights, look at 500–1000Wh portable power stations. With humidifier, double these figures.

Does my CPAP come with a battery backup?

Some do, most do not. Bedside machines such as the ResMed AirSense 10 and 11 have no battery inside and run from the wall. Travel machines such as the Transcend Micro, Breas Z1 and Z2, ResMed AirMini and Philips DreamStation Go have batteries made for them, usually sold separately and sometimes bundled. Check the box, look for "DC input" on the machine, or call your supplier. See the section above for how to test one before an outage.

Does Medicare cover CPAP battery backup?

Medicare Part B covers CPAP machines and supplies as durable medical equipment. Coverage for battery backup systems varies — some portable power stations used for CPAP are covered under certain circumstances. Contact your Medicare plan and CPAP supplier for specifics. Your physician may need to document medical necessity for battery backup coverage.