Medical Backup
Portable power station size for CPAP without humidifier and phone chargers for 24 hours
Use the default WattSizer rule: add running watts, then model the largest startup load while the other selected loads are already running.
The peak-starting assumption is driven by CPAP without heated humidifier. With the default 20% buffer, WattSizer rounds up to the next 100 watts.
| Appliance | Running | Starting | Source note |
|---|---|---|---|
| CPAP without heated humidifier | 45 W | 45 W | CPAP adapters and manufacturer manuals vary; default is a conservative no-humidifier planning value and not medical advice. |
| Four phone chargers | 40 W | 40 W | USB charger labels vary; default assumes several fast chargers in use at once. |
Try the load yourself
Edit this scenario
| Load | Running watts | Starting watts |
|---|---|---|
Power station estimate
For battery units, the selected running load needs about 0 Wh for 8 hours or 0 Wh for 12 hours before weather, battery age, and inverter losses.
Safety check
Never operate a fuel-burning generator indoors, in a garage, on a porch, or near open windows. Use a listed transfer switch or interlock installed by a qualified electrician for home wiring, and verify actual device nameplates before buying equipment.
Generator or power station?
Fuel generators are useful for motor loads and longer outages, while battery power stations are better for indoor-safe electronics and medical-device planning. For battery sizing, this selected running load is about 850 Wh for 8 hours with the same buffer.
Never operate a fuel-burning generator indoors, in a garage, on a porch, or near open windows. Use a listed transfer switch or interlock installed by a qualified electrician for home wiring, and verify actual device nameplates before buying equipment.
Medical-device backup should be reviewed with the device manufacturer, clinician, or power supplier. This calculator is only a planning estimate.