Trek4Tech

CPAP Runtime Calculator

How many nights will a power station actually run your CPAP? Set your machine's draw, your sleep hours, and a station — the calculator does the math we publish on every guide: usable capacity is rated Wh × 0.85 for inverter loss (or full rated capacity on 12V DC), and nights round down to half nights.

Runtime figures are calculated from manufacturer-published specs, not field measurements. Your machine's real draw varies with pressure and temperature — measure it with a plug-in watt meter for exact numbers. Method: how we research.

1. Your CPAP's average draw

2. Hours of sleep per night

3. Power station

4. How the CPAP is plugged in

Anker SOLIX C1000 Gen 2 · 62W × 8 hrs/night · AC inverter

1.5 nights

870Wh usable ÷ 496Wh per night = 1.75 — rounded down to half nights, because a night you finish at 80% is not a night. Total runtime ≈ 14.0 hours.

$699.99 · Amazon · checked Oct 19, 2026

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How the CPAP runtime calculator works

Three numbers decide how long a power station runs a CPAP: the station's rated capacity, your machine's average draw, and how many hours you sleep. The calculator uses the same formula as every CPAP guide on this site:

  • Usable Wh = rated Wh × 0.85 on the AC outlets (inverter loss, applied once). On a 12V DC cable the full rated capacity is available.
  • Wh per night = CPAP watts × hours asleep, used as-is.
  • Nights = usable Wh ÷ Wh per night, rounded down to the half night, so you never plan on a night the battery can't finish.

Worked example: a 1,024Wh station has about 870Wh usable on AC. A CPAP averaging 60W for 8 hours uses 480Wh a night. 870 ÷ 480 = 1.8, which rounds down to 1.5 nights.

CPAP runtime by power station (8-hour nights)

Nights per charge on the AC outlets for the stations in the calculator. 40W is a typical machine with the humidifier off, 60W with the humidifier on, and 90W with a heated hose as well.

StationRatedUsable (AC)40W60W90W
EcoFlow River 2 Pro Solar Generator (220W)768Wh~653Wh210.5
Anker SOLIX C1000 Gen 21,024Wh~870Wh2.51.51
EcoFlow DELTA 3 Portable Power Station1,024Wh~870Wh2.51.51
Jackery Explorer 1000 v21,070Wh~910Wh2.51.51
EcoFlow Delta 2 Max2,048Wh~1,741Wh53.52

CPAP runtime calculator FAQ

How long will a power station run a CPAP?

Divide the station's usable watt-hours by what your CPAP uses in a night. A 1,024Wh station has about 870Wh usable on AC. At 60W for 8 hours (480Wh a night) that's 1.5 nights; with the humidifier off at 40W (320Wh) it's 2.5 nights.

Why does the calculator use 85% of the rated capacity?

The AC outlets run through an inverter that loses roughly 15% as heat, so we apply 0.85 once, to the capacity. Running the CPAP on a 12V DC cable skips the inverter, which is why the calculator shows more nights in DC mode.

How many watts does my CPAP use?

It depends on the humidifier and heated hose more than the machine. ResMed publishes a typical draw of about 53W for the AirSense 10 and 56W for the AirSense 11. The figures by model are in how many watts a CPAP uses.

Why round down to half nights?

A battery that runs out at 4am hasn't given you a night. Rounding down means the number the calculator shows is a number of nights you can actually finish.

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