Backup Power for Medical Equipment: Sizing a Solar Generator for CPAP, Oxygen Concentrators, and Power Chairs

Last updated: 2026-07-07

For most households, a power outage means a few hours of inconvenience — melting ice cream, a dark living room, a mildly annoying dinner by flashlight. If someone in your home depends on a CPAP machine, an oxygen concentrator, a nebulizer, or a power wheelchair, an outage is a different category of problem entirely. These are not comfort devices. Sleep apnea therapy interrupted for a night is a real health setback, and for a homeowner or family member relying on supplemental oxygen, going without power isn't an inconvenience — it can mean a trip to the emergency room.

The good news: sizing backup power for medical equipment is one of the more straightforward calculations in the home backup world, because most of these devices draw far less power than people assume. This guide walks through exactly what CPAPs, oxygen concentrators, nebulizers, and power wheelchairs actually draw, how to size a portable power station correctly, and what to do differently than you would for a refrigerator or sump pump.

Why Medical Equipment Backup Is Its Own Category

Most home backup power guides start with the refrigerator, the sump pump, or the well pump — big, power-hungry appliances that need serious wattage and careful surge planning. Medical equipment is almost the opposite problem. A CPAP machine draws less power than a hair dryer. An oxygen concentrator draws roughly what a window fan does. The challenge isn't finding enough capacity — it's making sure the device never loses power even for a few seconds, and that the battery you're relying on is rated for the exact plug and waveform these devices expect.

There's also a reliability standard that's different from every other backup power use case in this guide. If your sump pump backup runs a little short, you clean up some water. If your CPAP backup runs short, someone doesn't get their prescribed therapy for the night — and if it's an oxygen concentrator, the stakes are considerably higher. That changes how much margin you should build in, and it's worth being conservative rather than cutting sizing close.

What Medical Devices Actually Draw

The numbers below are useful as planning figures, but always confirm the actual wattage on your specific device's label or manual — output varies by model, pressure setting, and oxygen flow rate.

| Device | Typical Draw | Notes |

|---|---|---|

| CPAP/BiPAP (no humidifier) | 30–60W | Most modern travel and home CPAPs |

| CPAP with heated humidifier | 60–90W | Humidifier heating element adds meaningful draw |

| Oxygen concentrator (portable) | 60–150W | Pulse-dose units draw less than continuous-flow |

| Oxygen concentrator (home stationary) | 300–600W | Continuous-flow units at higher liter-per-minute settings |

| Nebulizer | 100–200W | Only runs during treatment, not continuously |

| Power wheelchair charger | 100–300W while charging | Charges the chair's battery, doesn't run continuously |

| Electric hospital bed | 150–300W | Mostly used briefly for positioning, not continuous |

The most important distinction on this list is between devices that run continuously (CPAP overnight, a stationary oxygen concentrator around the clock) and devices that draw power only intermittently (nebulizer treatments, wheelchair charging, bed positioning). Continuous-use devices are what determine your runtime math — the intermittent ones are essentially free to add to a system already sized for the big continuous load.

Sizing for CPAP Alone

A CPAP machine without a humidifier drawing 40W runs for roughly 25 hours on a 1,000Wh battery before accounting for inverter losses — in practice, closer to 20–22 hours once you factor in the roughly 10–15% efficiency loss that comes with converting DC battery power to the AC power most CPAPs plug into. That's enough for two to three full nights of sleep on a single charge, even before any recharging.

Jackery Explorer 1000 — 1,002Wh capacity, 1,000W AC output

This is the practical sweet spot for CPAP-only backup. It's compact enough to keep on a nightstand, runs a standard CPAP for multiple nights per charge, and is light enough (about 22 lbs) for someone to move between rooms without help. If a heated humidifier is part of your setup, expect closer to 12–15 hours per charge rather than 20+, which is still more than one full night with margin to spare.

If your CPAP is your only backup power need, you don't need to size for surge the way you would for a well pump or refrigerator — a CPAP has no meaningful startup spike, so any unit with sufficient continuous wattage and Wh capacity will handle it without complication.

Sizing for Oxygen Concentrators

Oxygen concentrators are the device on this list where sizing mistakes carry the most risk, because a portable concentrator and a stationary home concentrator have very different power profiles.

Portable pulse-dose concentrators (the kind rated for travel) draw 60–150W and are the easier case — a mid-size power station comfortably runs one for 10+ hours per charge.

Stationary continuous-flow concentrators used at higher liter-per-minute settings can draw 400–600W continuously, and unlike a CPAP, this is not a device where you want to cut sizing close. A unit drawing 500W continuously will drain a 1,000Wh battery in under two hours accounting for inverter losses — nowhere near enough for an overnight or multi-hour outage.

EcoFlow DELTA 2 Max — 2,048Wh capacity, 2,400W AC output, expandable

For a stationary continuous-flow concentrator at 500W, this delivers roughly 3.5–4 hours on the base battery alone — and critically, it's expandable with an extra battery module, which is the right call for anyone whose household includes someone on continuous supplemental oxygen. Two battery modules roughly double runtime for a device that genuinely cannot be allowed to lose power partway through the night.

If your household includes a continuous-flow oxygen concentrator, talk to your equipment supplier about backup options specifically designed for medical oxygen delivery in addition to a general-purpose power station — some suppliers offer battery packs built and rated specifically for their concentrator model, and those should be your primary backup, with a portable power station as a supplement or second layer, not a replacement.

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Running Multiple Medical Devices Together

Many households aren't sizing for a single device — it's a CPAP for one person, a wheelchair charger, and maybe a nebulizer for someone else in the home. Add up the continuous loads (CPAP, concentrator) and treat intermittent loads (nebulizer treatments, wheelchair charging, occasional bed repositioning) as a smaller buffer on top, since they rarely all run at the exact same moment.

Example: a household running a CPAP with humidifier (75W continuous) alongside overnight charging for a power wheelchair (200W while charging, a few hours per night) is looking at roughly 275W of simultaneous draw during the worst-case overlap. A Jackery Explorer 2000 Plus (2,042Wh, expandable to much higher capacity) handles that combination for well over 24 hours per charge, with enough headroom to also keep phones charged and a lamp running.

The Feature That Matters More Than Capacity: Pass-Through and UPS Mode

For medical equipment, one spec matters more than raw battery size: whether the power station has a genuine uninterruptible power supply (UPS) mode with a fast transfer time. UPS mode means the unit stays plugged into wall power continuously, charging itself, and instantly switches to battery the moment grid power drops — with a transfer time typically under 20 milliseconds on EcoFlow and Jackery units with this feature.

This matters because it means the device is never actually relying on someone to notice the power went out and scramble to plug it into a battery. The power station is already in the circuit, all the time, and the switchover happens fast enough that a CPAP or concentrator never registers an interruption. If you take away one specification from this entire guide, make it this: confirm UPS/pass-through mode before buying, and set it up so the medical device is plugged into the station full-time, not just pulled out during emergencies.

Battery Chemistry and Why It Matters Here

Both EcoFlow and Jackery's current generation of power stations use LiFePO4 (lithium iron phosphate) battery chemistry rather than the older lithium-ion NMC chemistry. This is worth knowing specifically in a medical-equipment context: LiFePO4 batteries are rated for roughly 3,000–4,000 charge cycles before meaningfully degrading, versus 500–1,000 for older lithium-ion chemistry, and they run cooler and are considered safer for equipment that may sit plugged in and charging around the clock for months or years at a time — exactly how a medical backup unit is typically used.

Where to Keep It and How to Test It

Keep the power station in the same room as the device it's backing up, plugged in continuously via UPS mode, not stored in a closet for emergencies only. A backup system nobody has tested is not a backup system — it's a hope. Test the full setup monthly: unplug the power station from the wall (simulating an outage) and confirm the CPAP, concentrator, or other device keeps running without any interruption or alarm.

Talk to your durable medical equipment (DME) supplier or physician's office about your specific device's power requirements and any backup guidance they provide — this guide covers general sizing principles, but your supplier knows your exact model's specifications and may have equipment-specific recommendations, especially for oxygen concentrators and other devices where interruption carries meaningful health risk.

What This Costs vs. What's at Stake

A Jackery Explorer 1000 runs roughly $699–$899 depending on current promotions; an EcoFlow DELTA 2 Max runs $1,499–$1,699. Neither is a small purchase, but both function as general-purpose backup power beyond medical equipment — running a refrigerator during a summer outage, powering tools during a home project, or serving as camping and travel power the rest of the year.

Weighed against a night of missed CPAP therapy, an emergency room visit for oxygen desaturation, or the stress of not knowing whether a loved one's equipment will keep running during a storm, the cost of correctly sized backup power is a small price for a genuinely different kind of peace of mind than the rest of home backup power addresses. If you're deciding between a portable power station and a whole-home generator for the rest of the house, our comparison guide covers that broader decision, and our 72-hour outage sizing guide is useful if your outages tend to run multiple days rather than hours.

Start Here

The takeaway: medical equipment backup power is a sizing problem you can solve with real confidence, because these devices draw far less than a refrigerator or well pump — the CPAP-only household needs a Jackery Explorer 1000, a household with a continuous-flow oxygen concentrator needs an EcoFlow DELTA 2 Max with UPS mode, and every household running life-sustaining equipment should have that unit plugged in and tested monthly, not sitting in a closet waiting for an emergency.

Check current pricing on the Jackery Explorer 1000 or the EcoFlow DELTA 2 Max before your next storm watch, not during it.

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