Verify your watts
- Check the device label for running watts or input amps and volts.
- Use a plug-in watt meter for AC loads when the result matters.
- For cycling loads, measure long enough to capture on/off behavior.
CPAP battery backup guide
CPAP Battery Backup Guide
A cautious CPAP backup hub for choosing planning watts, nights, reserve, and power path before trusting a portable power station overnight.
Do not treat this as medical advice
Use these numbers only as a battery-planning estimate. For critical backup, follow the CPAP manufacturer's battery guidance, ask your clinician or equipment provider when needed, and test the exact setup before relying on it overnight.
Check output path
- AC inverter loads usually lose more energy than direct DC loads.
- Keep reserve for cold weather, battery age, and load changes.
- Do not treat label capacity as fully usable watt-hours.
Medical-device planning
- Use this site as a planning estimate, not medical advice.
- Follow the device manufacturer's battery guidance.
- Test the full setup before relying on it overnight.
Choose the closest CPAP power profile
Start with the closest generic profile, then replace it with your measured watts or manufacturer battery table when you have it.
Without heated humidifier
A lower-draw overnight profile for a CPAP setup with heated comfort accessories off.
- Planning wattage range: 30-60 W
- 8-hour load energy before station losses: 240-480 Wh
- Calculator default: 40 W
- Confidence: estimated
With heated humidifier or heated tube
A higher-draw profile for comfort heat. Heat settings can dominate battery size.
- Planning wattage range: 60-100 W
- 8-hour load energy before station losses: 480-800 Wh
- Calculator default: 85 W
- Confidence: estimated
Travel CPAP
A smaller-device planning profile. Confirm the travel adapter and battery cable path before depending on it.
- Planning wattage range: 5-20 W
- 8-hour load energy before station losses: 40-160 Wh
- Calculator default: 12 W
- Confidence: estimated
How to plan nights of backup
CPAP backup is a nights-of-use problem first, then a watts and power-path problem.
- Pick the scenario that matches humidifier and heated-tube use.
- Use 8 hours per night unless your prescribed sleep target is different.
- Prefer the manufacturer-supported DC path when available; AC inverter paths usually lose more energy.
- Keep reserve for battery age, cold conditions, pressure changes, mask leaks, and comfort settings.
- Run a full overnight test before trusting the setup during an outage.
AC vs DC path
The same CPAP can need a different battery class depending on the power path.
- AC inverter: Easiest to plug in, but inverter losses reduce usable Wh and the power brick still matters.
- Manufacturer-supported DC cable: Often more efficient, but only use a cable and voltage path the manufacturer supports.
- Power bank or USB-C adapter: Treat adapters cautiously. Confirm voltage, current, polarity, and overnight behavior before relying on them.
Sources and confidence
The hub uses source-linked generic ranges and keeps the confidence label estimated because exact draw depends on the prescribed device setup.
Next step
Use the calculator for your actual station and then save or print an outage plan if the setup matters.
CPAP backup FAQ
Should I plan with the humidifier on or off?
Plan the way you will actually sleep. If you might turn heat on during an outage, use the heated profile or measure the setup with heat enabled.
Is a calculated runtime enough for medical backup?
No. Treat runtime math as a planning estimate only. Follow manufacturer battery guidance and test the exact CPAP, cable, battery, and settings together.
Why does DC sometimes help?
A supported DC path can avoid inverter losses. It is only appropriate when the voltage, cable, and connector are manufacturer-approved for your setup.