Backup power for medical devices: generators, batteries and a plan for CPAP, oxygen and more

For people who rely on electrically powered medical equipment, a power outage is more than an inconvenience. Ready.gov advises anyone who uses medical equipment requiring electricity to talk to their doctor or health care provider about how to keep it running during an outage, and to ask their power provider about being put on a list for priority power restoration. This guide covers the practical side: how much power your devices need, the backup options, and how to put together a plan.

This information is general. Always follow your device manufacturer's instructions and your clinician's advice.

Step 1: List devices and their power needs

Common home medical devices include:

• CPAP and BiPAP machines. Draw varies widely with the humidifier and heated tubing. Without the humidifier, many draw tens of watts. With heat, they can draw much more.
• Oxygen concentrators. Often in the range of a few hundred watts for stationary units.
• Powered wheelchairs and scooters, which need battery charging.
• Nebulizers, used intermittently.
• Home ventilators, which usually have internal batteries and specific backup requirements.
• Feeding pumps, suction machines, infusion pumps, often battery-capable.
• Refrigerated medications, such as insulin. Ready.gov notes that if power is out for more than a day, you should discard medication that should be refrigerated unless the label says otherwise, and consult your doctor or pharmacist for a new supply.

For each device, find the watts or the volts and amps (watts = volts × amps) on the label or in the manual, and note whether it has an internal battery and how long it lasts.

Step 2: Choose a backup strategy

Manufacturer batteries. Many CPAP machines, concentrators, and ventilators have approved external or internal batteries. These are the simplest, safest first layer. They switch over seamlessly and work indoors.

Portable power stations. Lithium battery units with built-in inverters can run low-wattage devices for hours. To estimate runtime: battery watt-hours × about 0.85 (to allow for inverter losses) ÷ device watts. For example, a 1,000 Wh station running a 50 W CPAP gives about 1,000 × 0.85 ÷ 50 ≈ 17 hours. Turning off the humidifier typically extends runtime a lot. Check that the station's continuous and surge ratings exceed the device's draw, and that it provides a pure sine wave output.

Generators. A generator can run devices indefinitely with fuel and can recharge batteries. Inverter generators produce cleaner power, which is generally better for electronics. The best setup is often a generator that recharges a battery or UPS, with the device running from the battery. That way the device never loses power during refueling or if the generator stalls.

Uninterruptible power supply (UPS). A UPS can bridge short interruptions and the switchover to a generator. Check with the device maker whether a UPS is appropriate.

Step 3: Power quality matters

Some medical devices are sensitive to voltage fluctuations and waveform distortion. Prefer:

• inverter generators with low THD;
• pure sine wave power stations or UPS units;
• surge protection between the source and the device.

Avoid running medical equipment on the same cord or circuit as large motor loads, such as refrigerators, sump pumps, or well pumps, whose starting surges can cause momentary voltage dips.

Step 4: Register and communicate

• Utility priority programs. Ask your power company whether it has a medical certificate or priority restoration list. Programs vary, and none guarantee power will be restored first, but they may provide advance notice of planned shutoffs.
• Equipment supplier. Ask about backup batteries, loaner equipment, and emergency oxygen cylinders.
• Local emergency management. Some counties keep registries of residents who need help during emergencies.
• Family and neighbors. Make sure someone knows your plan and can check on you.

Step 5: Know when to go elsewhere

If an outage is long, your backup is running low, or conditions become unsafe, go somewhere with power: a family member's home, a shelter that can accommodate medical needs, or a hospital in an emergency. Ready.gov advises people on dialysis or other life-sustaining treatment to know the locations of more than one facility that can help. Decide in advance what conditions will trigger a move.

Generator safety is non-negotiable

People with breathing or heart conditions are especially vulnerable to carbon monoxide. The CDC notes that people with chronic heart disease, anemia, or breathing problems are more likely to get sick from CO. Run the generator only outdoors, more than 20 feet from windows, doors, and vents, and keep battery-powered CO alarms near sleeping areas. Never run a generator in a garage to keep it close to the device. Use a properly rated extension cord instead.

Testing your backup before you need it

A plan that hasn't been tested is a guess. At least twice a year:

• Run your device from its battery for the length of time you're counting on, and confirm the runtime.
• Charge the power station fully, run the device from it overnight, and note how much capacity is left in the morning.
• Start the generator, connect it, and confirm the device runs normally, with no alarms or error codes.
• Check battery ages. Many rechargeable batteries lose capacity over a few years, so replace them on the manufacturer's schedule.
• Make sure chargers, adapters, and cords are stored with the backup equipment, not in a drawer somewhere else.

Travel and evacuation

If you might have to leave, pack the device, its batteries, its charger, a car charger or DC adapter if available, a printed copy of your prescription settings, and a list of your supplier's contacts. Many devices can run from a vehicle's 12-volt outlet with the right manufacturer-approved adapter, which can be a useful bridge during evacuation.

A sample plan

1. Device: CPAP, 40 W without humidifier, 90 W with.
2. First layer: manufacturer battery, about one night.
3. Second layer: 1,000 Wh power station, about 2 more nights without humidifier.
4. Third layer: 2,200 W inverter generator to recharge the station daily, with 5 gallons of stored fuel.
5. Contacts: utility medical program, equipment supplier, family member.
6. Trigger to leave: if the outage is expected to last more than 3 days, or the generator fails.

Write your plan down, test it before you need it, and review it with your clinician each year.