Sizing a power station for medical equipment: CPAP, oxygen concentrators, home dialysis

If you or someone in your household depends on medical equipment that needs electricity — CPAP, oxygen concentrator, home dialysis, infusion pump — backup power isn't a comfort item, it's a clinical necessity. Sizing it right matters more than for any other application. Here are the real power draws by device class and how to size a portable power station for medically necessary loads.

CPAP and BiPAP

The FDA categorizes CPAP and BiPAP devices as Class II. Real power draws from major models:

• ResMed AirSense 11 (most prescribed): 30–40 W without humidifier, 60–95 W with heated humidifier on low, up to 125 W with heated tube on high.
• Philips Respironics DreamStation 2: 35–45 W base, 80–110 W with humidifier, 130 W full features.
• BiPAP (e.g., ResMed AirCurve 10): 50–65 W base, up to 140 W with all heating active.

For an 8-hour night without humidifier: 30 W × 8 = 240 Wh required, plus inverter losses = ~310 Wh from a power station. A 500 Wh LiFePO4 unit comfortably covers one night with margin. With humidifier on low, plan for 1 kWh.

Oxygen concentrators

Portable oxygen concentrators (POCs) draw more than CPAPs:

• Inogen One G5 (portable): 80–120 W average, 150 W peak during compressor surge.
• Inogen At Home (stationary, used at home): 280–350 W continuous.
• Respironics SimplyGo: 120 W average, 180 W surge.

Continuous use at 100 W from a 1 kWh unit = ~8 hours; from a 2 kWh unit = ~16 hours. For the stationary At Home unit at 300 W, a 2 kWh power station gives roughly 5 hours — enough to bridge a typical outage but not a multi-day event. FDA home-use device guidance recommends having backup power planning documented as part of clinical home-oxygen protocols.

Home dialysis

Peritoneal dialysis cyclers (Baxter HomeChoice, Liberty Cycler) and home hemodialysis machines (NxStage System One) have specific power requirements that demand careful sizing:

• NxStage System One: 600–800 W during pump operation, 1,200 W surge. A 4–5 hour treatment uses 2,400–3,200 Wh.
• Baxter HomeChoice Pro: 350 W continuous during cycles, 800 W warmer-element draw intermittent.

For a single 4-hour NxStage treatment you need 3+ kWh and a pure sine wave inverter rated for 1,500 W+ surge. The EcoFlow Delta Pro 3, Bluetti AC500 + B300, or Anker SOLIX F3800 are realistic options. Smaller units cannot reliably support a full treatment.

The bare-minimum sizing rule

For any medical device:

1. Find the device's actual power draw in its manual (in watts, or amps × volts).
2. Multiply by hours of expected outage (plan for 24-hour minimum).
3. Divide by 0.80 (the realistic delivery ratio after inverter and BMS losses).
4. Add 30–50% margin.
5. Verify pure sine wave inverter — modified sine wave damages many medical devices and is unsafe for life-support.

Then verify the surge rating exceeds your device's surge spec (usually 3× running watts for motor-driven devices).

Sources & further reading

• Sleep Disorder Treatment Devices (CPAP/BiPAP) — U.S. Food and Drug Administration
• Home Use Medical Devices — U.S. Food and Drug Administration
• Standards in Medical Device Safety — Association for the Advancement of Medical Instrumentation (AAMI)
• Durable Medical Equipment Coverage — U.S. Centers for Medicare & Medicaid Services