25-60W
Per Night
50Ah+
Min Battery
100W
Solar Panel
CPAP solar power is straightforward because CPAPs are low-draw devices. Without a humidifier, most CPAPs use just 25-40W - a 50Ah LiFePO4 battery covers 2+ nights. With a heated humidifier (50-60W average), a 100Ah battery handles 2-3 nights. One 100W solar panel recharges enough for the next night in 4-5 hours of sun.
If you rely on CPAP therapy, losing power isn't just inconvenient - it's a health risk. Whether you're camping, living off-grid, or preparing for power outages, CPAP solar power lets you keep your therapy running indefinitely with the right battery and panel setup.
The good news: CPAPs are one of the easiest medical devices to run on solar. They draw less power than a single light bulb. Here's exactly what you need.
CPAP Power Draw by Model
CPAP power consumption varies dramatically based on the model and whether you use a heated humidifier. The humidifier roughly doubles your power draw.
| CPAP Model | Without Humidifier | With Humidifier | 8-Hr Energy (No Hum.) |
|---|---|---|---|
| ResMed AirSense 10 | 30-53W | 60-104W | 240-424Wh |
| ResMed AirSense 11 | 25-40W | 56-73W | 200-320Wh |
| ResMed AirMini (travel) | 20-30W | N/A (waterless) | 160-240Wh |
| Philips DreamStation 2 | 25-45W | 55-80W | 200-360Wh |
| Philips DreamStation Go | 20-35W | N/A (waterless) | 160-280Wh |
| Lowenstein Prisma | 30-50W | 60-90W | 240-400Wh |
| Travel CPAP (typical) | 20-30W | N/A | 160-240Wh |
The heated humidifier doubles your power draw. For camping and emergency backup, consider running without it. Use a heat moisture exchanger (HME) filter instead - it captures moisture from your breath and returns it. Costs $2-5 per filter and cuts your power needs in half.
The wattage ranges above reflect different pressure settings. Higher prescribed pressure means the motor works harder and draws more power. Your actual draw depends on your therapy pressure (typically 7-15 cm H2O).
Battery Runtime: How Many Nights Per Charge?
Runtime (hours) = Battery Wh ÷ CPAP watts
| Battery | Usable Wh | CPAP Only (30W) | CPAP + Hum (60W) |
|---|---|---|---|
| 25Ah LiFePO4 | 320Wh | 1 night | ~5 hrs |
| 50Ah LiFePO4 | 640Wh | 2-3 nights | 1 night |
| 100Ah LiFePO4 | 1,280Wh | 5+ nights | 2-3 nights |
| 200Ah LiFePO4 | 2,560Wh | 10+ nights | 5+ nights |
| 50Ah AGM | 300Wh | 1 night | ~4 hrs |
| 100Ah AGM | 600Wh | 2 nights | 1 night |
LiFePO4 runtime assumes 100% depth of discharge (usable). AGM runtime assumes 50% DoD to protect battery life. See our LiFePO4 vs AGM comparison for why LiFePO4 delivers 2x the usable energy from the same amp-hour rating.
DC vs AC: The 15% Efficiency Gap
Most people plug their CPAP into an inverter, which converts 12V DC battery power to 120V AC. The CPAP's own power adapter then converts it back to DC. This double conversion wastes 10-15% of your battery as heat.
| Feature | AC (via inverter) | DC (direct) |
|---|---|---|
| Power path | Battery → Inverter → CPAP adapter → CPAP | Battery → DC cable → CPAP |
| Efficiency | ~85% | ~98% |
| Effective runtime | Base | +15-20% longer |
| Equipment needed | Inverter ($50-150) | DC adapter cable ($15-30) |
| Noise | Inverter fan may hum | Silent |
Most ResMed machines accept 12V or 24V DC input. Philips DreamStation uses a proprietary DC connector. Always buy the DC cable made for your specific CPAP model - a wrong voltage will damage the machine. ResMed sells an official DC/DC converter (model 24893) for $25-30 that works with AirSense 10 and 11.
Going DC means you don't need an inverter at all if the CPAP is your only load. That saves $50-150 on the inverter AND gives you 15% more runtime from the same battery. For a dedicated CPAP backup system, DC is the clear winner.
Solar Panel Sizing for Daily CPAP Recharge
The goal is simple: your solar panel needs to replace the energy your CPAP used overnight, plus account for charging inefficiency (~20% loss through the charge controller).
| CPAP Setup | Nightly Use | Need to Replace | Panel Size (4 sun hrs) |
|---|---|---|---|
| Travel CPAP (no hum.) | 200Wh | 240Wh | 60W |
| Standard CPAP (no hum.) | 300Wh | 360Wh | 100W |
| Standard CPAP + humidifier | 500Wh | 600Wh | 150W |
| High-pressure + humidifier | 650Wh | 780Wh | 200W |
Panel sizes assume 4 peak sun hours per day (typical US average). Cloudy or northern climates may get 2-3 hours, requiring a larger panel. Southern/desert areas may get 5-6 hours.
Complete CPAP Solar Systems by Use Case
Emergency Backup (1-2 nights)
$80-150Keep at home for power outages. No solar needed if outages are short.
Camping / Weekend Trips
$200-350Solar recharges the battery each day for indefinite runtime.
Full Off-Grid / Extended Outage
$350-550Handles humidifier use, cloudy days, and other small loads.
For help sizing a battery bank that covers your CPAP and other loads, use our Battery Bank Sizing Calculator. For detailed runtime math, see How Long Will a 100Ah Battery Last?
If you're building a larger off-grid system and need to decide how to wire your batteries, read our series vs parallel battery wiring guide.
Frequently Asked Questions
What size battery do I need for a CPAP machine?
For one night without a humidifier, a 50Ah LiFePO4 battery (640Wh) gives you 2+ nights of runtime. With a heated humidifier, you need about 400-600Wh per night, so a 100Ah LiFePO4 (1,280Wh) covers 2-3 nights. For camping trips, size for the number of nights plus one extra as a buffer.
Can a 100Ah battery run a CPAP all night?
Yes, easily. A 100Ah LiFePO4 battery provides 1,280Wh of usable energy. Even a high-draw CPAP with heated humidifier at 60W uses only 480Wh per 8-hour night. A 100Ah battery runs most CPAPs for 2-4 nights without recharging.
How many solar panels do I need to recharge a CPAP battery?
A single 100W solar panel produces about 400-500Wh per day in good sun (4-5 peak sun hours). Since a CPAP uses 200-500Wh per night depending on the model and humidifier, one 100W panel is enough for most setups. Add a second panel if you use a heated humidifier or get limited sun.
Should I run my CPAP on DC or AC power from a battery?
DC whenever possible. Running through an inverter (DC to AC) wastes 10-15% of your battery as heat. Most ResMed and Philips CPAPs accept 12V or 24V DC input with an adapter cable ($15-30). This extends your battery runtime by 15-20% compared to using an inverter.
Can I use a portable power station for my CPAP?
Yes. A portable power station with 500Wh+ capacity runs most CPAPs for 1-2 nights. Popular options include the Jackery 500 (518Wh), EcoFlow River 2 (256Wh, 1 night without humidifier), and Bluetti EB3A (268Wh). For multi-night trips, pair with a solar panel for daily recharging.
Methodology & Sources
CPAP wattage data compiled from manufacturer specification sheets and real-world user measurements. Battery runtime calculations use standard P = V x I formulas with LiFePO4 at 100% DoD and AGM at 50% DoD.
- ResMed specs: AirSense 10/11 clinician manuals and DC battery guide (document 198103)
- Solar sizing: NREL PVWatts calculator for peak sun hour averages by region
- Inverter efficiency: Industry standard 85-90% for pure sine wave inverters at partial load
- How Long Will a 100Ah Battery Last? - Runtime for CPAPs and other common devices
- LiFePO4 vs AGM for Solar Storage - Why LiFePO4 is ideal for CPAP backup
- Series vs Parallel Battery Wiring - How to wire larger battery banks
This content is for informational and planning purposes only. Always consult a licensed electrician or qualified professional before making electrical installations or purchasing decisions. See our terms of use.