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Find my setup

CPAP battery calculator

How big a power station your CPAP needs for the nights you plan. The default is 40 W for 8 hours, two nights, without a heated humidifier; change the watts to your machine's.

CPAP

Watts are typical averages; the label on your device wins. Set sun to 0 to size the battery alone.

You use
320 Wh
a day
Battery you need
753 Wh
2 days, 15% conversion loss
Output you need
40 W
60 W to start the biggest
Solar to keep up
none
add sun hours to size it

70 stations fit, cheapest first

EcoFlow RIVER 2 Pro768 Wh · 800 W · 220 W solar · 2 days of this load$389BLUETTI Elite 100 mini1,005 Wh · 700 W · 350 W solar · 3 days of this load$429BLUETTI Elite 100 V21,024 Wh · 1,800 W · 1,000 W solar · 3 days of this load$489EcoFlow DELTA 3 Classic1,024 Wh · 1,800 W · 500 W solar · 3 days of this load$499BLUETTI AC1801,152 Wh · 1,800 W · 500 W solar · 3 days of this load$499Jackery Explorer 1000 v21,070 Wh · 1,500 W · 400 W solar · 3 days of this load$519Jackery HomePower 1000 v21,024 Wh · 1,500 W · 400 W solar · 3 days of this load$549Anker SOLIX C1000X1,056 Wh · 1,800 W · 600 W solar · 3 days of this load$600

Quick answers

How big a power station do I need for this?

About 753 Wh of battery for 2 days (320 Wh a day plus 15% conversion loss), with at least 40 W of output. 70 stations we track fit; the cheapest today is the EcoFlow RIVER 2 Pro.

How do you work it out?

Each item's watts times its hours a day gives watt-hours. The battery must hold that for each day without recharging, divided by 0.85 for conversion loss. Solar needed is a day's use divided by the hours of good sun, with panels at 70% of their rating.

Does a heated humidifier change the answer?

Yes, a lot. Heated humidifiers and heated hoses can use several times the power of the CPAP motor. Check the watts on your machine's power supply, or run it from its DC cable where the maker offers one, which skips the inverter.

We may earn a commission if you buy through these links. It never changes a verdict. How the math works.