CPAP: how much battery you need
CPAP (no humidifier) draws about 35 W (25–60 W range), runs 100% of the time and uses 280 Wh per day. Start-up surge: 40 W.
~300 Wh a night without the heated humidifier, 600–800 Wh with it. Use the DC cable (12/24 V) from the station to skip inverter losses.
Battery needed
| Hours | Wh | Battery (Wh) | Inverter (W) |
|---|---|---|---|
| For 8 hours | 93 | 142 | 39 / 40 |
| For 24 hours | 280 | 425 | 39 / 40 |
| For 72 hours | 840 | 1273 | 39 / 40 |
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Stations that fit (24 h)
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FAQ
How many watts does a CPAP (no humidifier) use?
Typically 35 W while running, with a range of 25–60 W depending on model and age. Start-up surge can reach 40 W.
How long will a 1000 Wh power station run a CPAP (no humidifier)?
About 18.9 hours on the clock, allowing for the 100% duty cycle, inverter losses and a 20% reserve.
What size power station do I need for a CPAP (no humidifier) overnight (8 h)?
About 142 Wh of battery and an inverter rated at least 39 W continuous with 40 W surge.
Can I run a CPAP (no humidifier) on solar during an outage?
You need roughly 187 W of panels in winter to replace a day's use (280 Wh), charging through a station with a big enough MPPT input.
Other sizes
Other appliances
1 Approximate values: estimated from motor or heater power and typical figures published online, not from a manufacturer chart. Check your appliance label.
Inverter efficiency 88%, usable depth of discharge 90%, reserve 20%. Full method: How we calculate. source