Medical backup power is where outage planning stops being about comfort. These questions come from patient and caregiver forums, and they deserve answers stated as facts — manufacturer specs, published thresholds, runtime math with the derating shown — not advice. What a machine draws and how long a battery lasts are facts we can give you. Decisions about care belong to your oxygen supplier, your pharmacist, and your home-health provider, and these pages will keep pointing you back to them. This shelf hangs off our Power hub.
The runtime questions
How long will a power station run an oxygen concentrator?
A home concentrator draws roughly 300–600 watts depending on its flow setting, so a 2 kilowatt-hour station runs one about 3–5 hours — a bridge that buys time to arrange tanks, a generator, or a move, not a full night at high flow. The honest plan is built around that number, not around hoping it’s bigger.
How long will a power station run my CPAP?
About 4 nights with the heated humidifier on, or 5–6 with it off, on a 2 kilowatt-hour station — the humidifier is nearly the whole spread. Our runtime page works the same question for fridges and freezers with the same math (a station really delivers about 85% of its rated watt-hours).
Covered in: How long will a power station run your CPAP, fridge, or freezer?
How long will a 12-volt car battery run a CPAP machine?
About 5.6 hours with the heated humidifier on, and about 8.6 hours with it off through a DC converter — a 60 amp-hour car battery holds 720 watt-hours on paper, but only about half is safely usable, and the conversion takes its cut too. Our CPAP runtime calculator runs the same math for your battery and your machine’s exact draw, on DC or AC.
Oxygen concentrator: Draws roughly 300–600 watts by flow setting — a 2 kWh station runs one about 3–5 hours, a bridge, not a full night.
CPAP on 2 kWh: About 4 nights with the heated humidifier on, or 5–6 with it off.
CPAP on a car battery: A 60 Ah battery holds 720 Wh on paper, about half safely usable: about 5.6 hours with the humidifier on, 8.6 off.
The medicine question
Keeping insulin and fridge medicines safe in an outage
The numbers that govern it: refrigerated insulin belongs at 36–46°F, freezing ruins it as surely as heat does, and most in-use insulin tolerates room temperature (below about 77–86°F, depending on the product) for a stated number of days on its label. A fridge on a mid-size station holds temperature for a day or more; after that, the plan is a cooler, ice packs, and a thermometer you trust — and your pharmacist is the authority on your specific product.
The planning question
What belongs in place before the outage, not during it?
Three things, all free: your name on the utility’s medical-priority or life-support registry if you qualify (it does not guarantee faster restoration, and the page should never pretend otherwise — it does get you notified); your oxygen supplier’s after-hours number and their tank-loaner policy in writing; and your concentrator’s actual draw measured with a plug-in watt meter, because the whole plan is arithmetic built on that one number.
How we answer
Ordinary Prepper is a research desk, not a test lab, and not a medical practice. Power figures come from manufacturer specifications; storage thresholds from the manufacturers’ and FDA labelling; runtime uses the same honest 85% factor as our power sizer. Facts here, care decisions with your providers — that line does not move.