Disclosure: This page contains affiliate links. We may earn a commission if you buy through them. Last updated: 21 September 2026. This is battery sizing, not medical advice. Follow the device maker. Keep a backup plan if the station fails. Evidence: manufacturer watt ranges and planning duty. We do not operate an in-house lab. How we review.
A power station for CPAP is a small, high-stakes load. Watts are modest. Hours are not. The machine runs most of the night. The humidifier is the tax that turns a travel pack into a 1 kWh conversation.
Size it the same way as every load on this site: running watts, surge (usually small), hours, then usable watt-hours.
CPAP night math and humidifier tax: CPAP load card.
Method: Size the Load.
The three numbers
| Number | Typical range | What it decides |
|---|---|---|
| Running watts, no humidifier | 30–60 W | Whether a 256–300 Wh travel station can finish one night |
| Running watts, with humidifier | 50–90 W | Whether you step up a class |
| Night length | 6–8 hours (plan 8) | Energy, not the inverter |
Surge on most CPAP units is mild (often 60–120 W). The fridge problem is surge. The CPAP problem is hours × humidifier.
Read your machine label or manual. If it lists amps: watts ≈ volts × amps. Do not use a neighbor’s number.
Energy math (site default 85% usable)
Wh needed ≈ watts × hours
Then sticker ≈ Wh needed ÷ 0.85
Example A — no humidifier, 45 W, 8 hours
45 × 8 = 360 Wh load → 360 ÷ 0.85 ≈ 424 Wh sticker.
A 256–300 Wh pack is tight (one night, little reserve, no charging the phone).
Example B — humidifier on, 70 W, 8 hours
70 × 8 = 560 Wh load → ≈ 659 Wh sticker.
River-class ~286 Wh is no longer honest. Step toward 500 Wh–1 kWh.
Example C — machine + router, humidifier off
(45 + 12) × 8 = 456 Wh load → ≈ 536 Wh sticker.
Same math as the CPAP worked example on Size the Load.
Add phone charging or a second night without wall power and the 1 kWh class stops being “overkill.”
Humidifier, heated tube, altitude
- Humidifier off: smallest honest pack.
- Humidifier on: size up one class.
- Heated tube / heated humidifier: treat as the high end of the 50–90 W band until the manual says otherwise.
- Cabin or altitude: follow the device maker, not a power-station ad. This page does not adjust therapy pressure.
Station classes that belong here
| Class | Sticker Wh | Honest CPAP job | Not for |
|---|---|---|---|
| Travel 256–300 Wh, ~300–600 W | Tight one night, humidifier off, efficient machine | Humidifier + second night | |
| 500 Wh class | One night with more reserve | Two nights, no recharge | |
| 1 kWh class | Humidifier, router, phone, morning margin | Using it only because an ad said “home backup” |
River-class ~286 Wh / 600 W is a travel and efficient-CPAP candidate only when the humidifier is off and you accept little reserve. Household fridge math lives on Refrigerator — do not buy a CPAP travel pack to start a top-freezer.
What this page will not do
- Recommend a therapy mode, mask, or pressure.
- Tell you a station is “medical grade” because the brand said so.
- Treat a power station as your only overnight plan.
- Use sticker watt-hours as “8-hour runtime” without watts and the 85% factor.
FAQ
Often yes, if watts × 8 hours fit inside usable watt-hours. Confirm the machine label. Humidifier on changes the answer.
Plan ~360–560 Wh of load for eight hours in the ranges above, then divide by 0.85 for sticker. Your manual wins.
Not if the humidifier is off and you only need one night. Yes if you want reserve, humidifier, or a second night without wall power.
No. Battery sizing only.
How the numbers are sourced: How we review.
Fridge is a different load: Refrigerator.
Corrections: Contact.
Disclosure: Affiliate disclosure.