Target
2 nights (16 hours)
Target-duration planning
Run a CPAP for 2 nights from a power station
This pilot uses an explicit 8-hour-per-night planning target and the no-heated-humidifier CPAP scenario. Change the hours and watts if your prescribed setup differs.
Planning load
40 W
- Running watts: 40 W
- Duty cycle (%): 100%
Estimated nominal battery
850 Wh+
Scenario confidence
estimated
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.
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.
Reverse runtime formula
This page solves for battery Wh instead of asking how long a battery lasts.
Load energy
40 W × 2 nights (16 hours) = 640 Wh
Usable factor
85% × 90% × 100% × 100% = 0.77
Estimated nominal battery
640 Wh ÷ 0.77 ≈ 850 Wh
Scenario behavior
The CPAP no-humidifier scenario is treated as a continuous load. Heated humidifiers, heated tubes, pressure, mask leaks, and AC vs DC power paths can change draw materially.
Wh-class guidance
Use the computed Wh as a no-humidifier planning floor. Add a larger margin or switch to the heated-humidifier scenario when comfort accessories are enabled.
Assumptions used
- CPAP without heated humidifier: 30-60 W
- Efficiency (%): 85%
- Reserve kept unused (%): 10%
- Output path: AC inverter
- Battery health (%): 100%
- Cold weather loss (%): 0%
Caveats
- For critical medical backup planning, follow the device manufacturer's battery guidance.
- Test the exact CPAP setup before relying on it overnight.
- Keep an independent backup plan for medical-adjacent use.
Sources
Humidifiers and heated tubes can more than double power draw. Users should check their device label and prescription setup.
Next steps
This pilot uses an explicit 8-hour-per-night planning target and the no-heated-humidifier CPAP scenario. Change the hours and watts if your prescribed setup differs.