For most people, a mid-sized Bluetti with roughly 500 to 1,000 Wh of capacity covers one night of CPAP use. The right size depends on your machine's draw, and especially on whether you run a heated humidifier. Check your device's power label, do the math below, then confirm current Bluetti models and specs on the official site.
How to size it
Find your CPAP's wattage on its label or in the manual. Multiply by hours of sleep, then add about 20% for inverter losses. The figures below are illustrative assumptions, not measurements of your machine.
| Setup (assumed average draw) | 8-hour night | With ~20% losses |
|---|---|---|
| CPAP only, ~40 W | 320 Wh | ~385 Wh |
| CPAP with light humidity, ~60 W | 480 Wh | ~575 Wh |
| Heated humidifier and tube, ~100 W | 800 Wh | ~960 Wh |
Divide a power station's rated watt-hours by your nightly figure to estimate how many nights it lasts. Usable capacity is a little lower than the rating, so leave some margin.
What matters besides capacity
- Humidifier use. This is the biggest variable. Turning heated humidification down, or using a different setting, can cut consumption a lot.
- DC power. Some CPAPs accept a 12V DC cable, which can be more efficient than running through an AC inverter. Use only the cable your CPAP manufacturer approves.
- Noise. Check the fan behavior in the model's specs, since you'll be sleeping beside it.
- Recharging. If an outage lasts several days, you'll need a plan such as solar input. Check each model's compatible charging options.
- Switchover behavior. Some models advertise UPS-style backup. Confirm how a specific model handles that, because a brief interruption could wake you.
Recommended for youBest Bluetti for Home Backup: Sizing a Setup for Power Outages and Emergency PrepA note on safety
If your breathing therapy is medically essential, don't rely on a single backup. Ask your doctor or equipment supplier about outage plans and about any manufacturer guidance for your machine. Test your full setup, including the humidifier, on a normal night before you need it in an emergency.
Choosing a model
If you only need a CPAP, a smaller unit may be enough. If you also want to keep a fridge, lights or a phone charger running, size for the total load. Our Best Bluetti Power Station: Which Model to Buy by Budget and Use page compares current options, and Choosing the Right Bluetti for Your Situation can help you weigh the trade-offs.
Related
- Best Bluetti for Home Backup: Sizing a Setup for Power Outages and Emergency Prep
- Best Bluetti for Camping, Car Camping and Overlanding
- How do you power essentials quietly without a gas generator?
Keep reading
Best Bluetti for RVs and Van Life: Picking Capacity, Charging and ExpansionThe best Bluetti for an RV or van is the one whose capacity, charging inputs and expansion options…
Best Bluetti for Camping, Car Camping and OverlandingStart with what you actually need to run The best Bluetti for camping is the one sized to your load…
Best Bluetti for Off-Grid Cabins: Solar, Batteries and Appliance PlanningAn off-grid cabin asks more of a power station than a camping trip or a short outage does. You are…