CPAP overnight backup: conservative battery sizing
An eight-hour AirSense 11 planning example with phone charging, 30% extra energy margin and explicit medical-device cautions.
Battery target for the night
Stated battery capacity, including a 30% extra energy margin on demand and 80% usable energy.
Adjust this exampleAt the official 56.1W typical AirSense 11 figure plus phone charging, the example uses about 479Wh. With 30% extra energy margin and an 80% usable-energy allowance, the rated battery target is about 778Wh.
- Energy per day
- 479 Wh Power × hours × quantity
- Power check
- 71 / 88 W Simultaneous / peak — planning values
- Solar target
- 250 W 3 peak sun hours · 75% yield
Solar is a separate estimate. The battery target is calculated without intermediate recharging.
Define your power requirements for Ireland.
No product is presented as an Irish candidate until its exact 230V/50Hz Type G execution, Irish delivery, warranty, support and seller evidence are verified.
778 Wh
Includes days, the extra energy margin on demand and the 80% usable-energy allowance
71 W · 88 W
Verify the exact appliance and inverter together
230V · 50Hz · Type G
Confirm the exact model delivered to Ireland, the supplied Type G leads and socket layout, and Irish warranty and support before relying on the setup; no verified Irish retailer, price, stock or affiliate offer is presented, and a UK or Northern Ireland route is not treated as Irish evidence
The devices in this example
These are sensible starting values. Change the hours and exact devices in the planner to make the answer yours.
CPAP planning load
449 Wh per day- Average consumption
- 56.1 W
- Entered peak
- 73.2 W
- Hours per day
- 8 hours
- Quantity
- 1
Phone charging
30 Wh per day- Average consumption
- 15 W
- Entered peak
- 20 W
- Hours per day
- 2 hours
- Quantity
- 1
This calculation is not a backup plan
Test the exact machine, power supply, humidifier, heated tube and station for a complete night. Follow the manufacturer and clinician.
Comfort settings change consumption
Heated humidification can materially change runtime. Do not change therapy settings based on a battery estimate.
Calculation detailsSee the assumptions behind this answer
- AirSense 11 uses its official 56.1W typical figure for eight hours
- The entered 73.2W peak is checked separately
- Phone charging adds 30Wh
- A larger 30% extra energy margin is used because this is a critical load
How the battery target is formed
479 Wh per day × 1 day × 1.3 ÷ 0.8 ≈ 778 Wh
The daily consumption above is rounded for display. The calculation uses unrounded values. The factor is 1 + the extra energy margin, added to demand rather than kept as battery charge; the 80% usable-energy allowance is a separate factor.