Medical Device Power Outage Planning: A Caregiver's Battery Backup Checklist

Power outages in the United States affect millions of households each year. According to FEMA, the average outage lasts 4 to 6 hours, but major weather events regularly push outages past 24 hours and sometimes past a week. Medical devices do not have a pause button. When the grid goes down, a CPAP machine stops delivering air, an oxygen concentrator stops producing oxygen, and a nebulizer stops generating medication mist.

This article is a practical, step-by-step planning guide. It is designed to be bookmarked, printed, or shared with family members. Every wattage figure comes from OEM specifications or conservative engineering estimates verified against our device database. But no guide replaces a conversation with your physician or home medical equipment (HME) provider about your specific needs.

This checklist reduces risk, but it cannot guarantee continuous operation of any medical device. Battery backup equipment can fail, degrade, or behave differently than expected. Always follow the device manufacturer’s guidance and your clinician’s instructions. This guide is informational — it is not medical advice.

Step 1: Inventory Your Medical Devices

Before you can size a backup battery, you need to know exactly what you are powering. Write down every medical device in your household that requires electricity, along with its wattage and daily usage hours.

Common medical device power draws

Device	Typical running watts	Daily hours	Daily Wh
CPAP machine	39–56W	8	312–449 Wh
Portable oxygen concentrator	~120W (operating)	up to 24	~2,880 Wh
Stationary oxygen concentrator	310–350W	up to 24	7,440–8,400 Wh
Nebulizer (compressor type)	25–140W	1–2	25–280 Wh
Electric wheelchair charger	121–341W	6–8	726–2,728 Wh

CPAP figures are from OEM user guides: Fisher & Paykel SleepStyle at 39W, ResMed AirSense 10 at 53W, ResMed AirSense 11 at 56.1W. The 312–449 Wh range reflects an 8-hour sleep session across these models. See our CPAP battery backup guide for model-specific data.

Oxygen concentrator figures distinguish portable from stationary units. The Philips SimplyGo draws approximately 120W during normal operation (150W while simultaneously charging its internal battery). Stationary units like the Philips EverFlo (350W) and Drive DeVilbiss 5L (310W) draw far more and run 24 hours a day. See our oxygen concentrator battery backup guide for detailed runtime calculations.

Nebulizer, wheelchair charger, and other device figures are approximate ranges from our database and published specifications. The range is wide because technology varies significantly — a portable mesh nebulizer draws under 25W while a home piston compressor nebulizer can draw 140W. Always verify against your specific device’s nameplate.

Use your exact model’s specs. Look at the label on the back of your device or the power supply brick, or check the manufacturer’s user manual. Do not rely on generic wattage charts or category averages — two CPAP machines from the same brand can differ by 17W, and two oxygen concentrators can differ by 230W. For oxygen concentrators specifically, confirm power draw at your prescribed flow rate and settings, because higher LPM settings and features like heated humidifiers increase power consumption.

Step 2: Calculate Your Battery Needs

Once you have your device inventory, the math is straightforward. Add up the daily watt-hours for all devices, then account for real-world battery losses and a safety margin.

Minimum battery capacity for medical backup

Total Daily Wh / 0.70 derate × 1.20 safety margin = Minimum Battery Capacity (Wh)

The 0.70 derate factor accounts for inverter conversion losses, battery voltage sag, and reduced efficiency at partial loads. The 1.20 safety margin (20% extra) is specific to medical devices — you cannot afford to run the battery to zero with life-critical equipment.

Example: CPAP user

A ResMed AirSense 11 at 56.1W for 8 hours = 449 Wh. Add phone charging at 50 Wh. Total daily need: 499 Wh.

499 Wh / 0.70 × 1.20 = 856 Wh minimum battery capacity for one night.

Example: Stationary oxygen concentrator user

A Philips EverFlo at 350W for 24 hours = 8,400 Wh. Add phone and light at 75 Wh. Total: 8,475 Wh.

8,475 Wh / 0.70 × 1.20 = 14,529 Wh minimum for one full day.

This number illustrates why a single portable power station is not a complete solution for stationary oxygen concentrators. Even the largest units on the market hold approximately 4,000–5,000 Wh. You need an expandable system, solar recharging, or a backup generator to cover a full day.

Multi-day planning

Multiply the daily minimum by the number of days you want covered. For CPAP: 856 Wh × 3 nights = 2,568 Wh for a 3-day outage. For stationary oxygen: multi-day coverage requires a system approach (see Step 3).

Step 3: Choose Your Backup Power Source

Tier 1 — One night (CPAP, nebulizer, phone)

Need: 500–1,000 Wh of backup power. A single CPAP session plus phone charging and a light.

Any power station rated 500W or above with at least 500 Wh capacity handles a CPAP machine comfortably. Pure sine wave output is required — all portable power stations in our database use pure sine wave inverters, but verify before purchasing any unit not in our listings. At this tier, size and weight matter because you may need to transport the unit. Our best power stations for CPAP machines page ranks every unit in our database by CPAP compatibility.

Tier 2 — Two to three days (CPAP + essentials)

Need: 2,000–4,000 Wh. Multiple nights of CPAP plus continuous phone, light, and a small fan or radio.

Expandable systems with add-on battery packs provide the most flexibility at this tier. The Jackery Explorer 2000 Plus (2,042 Wh base, expandable to approximately 12,000 Wh) is an example of a scalable approach — start with the base unit and add capacity as your budget allows.

Tier 3 — Extended or oxygen concentrator backup

Need: 4,000+ Wh, ideally expandable. Stationary oxygen concentrators require system-level planning.

A single 4,096 Wh power station (like the EcoFlow DELTA Pro 3) provides approximately 8.2 hours for a stationary concentrator at 350W — one third of a day. For full-day coverage, you need either:

Expansion batteries to reach 12,000+ Wh (roughly 24 hours at 350W)
Solar recharging with 400–600W of panels to offset daytime consumption
A portable concentrator at 120W if your prescription allows it (roughly tripling battery runtime)

Consult your physician before switching from stationary to portable — flow rate limitations may make a portable unit medically insufficient. Our best power stations for oxygen concentrators page shows which units can handle both portable and stationary models.

Step 4: Set Up and Test

A battery backup that has never been tested is not a backup. It is a hope.

Monthly test. Unplug your medical device from the wall and plug it into the fully charged power station. Run it for at least 30 minutes. Confirm the device operates normally, the power station does not trip or alarm, and the displayed wattage matches expectations.

Pass-through charging (UPS mode). Some power stations can act as an uninterruptible power supply: the station stays plugged into the wall, your device stays plugged into the station, and the station switches to battery automatically when the grid fails.

The critical specification is switchover time — how many milliseconds the transition takes. For most medical devices, a brief interruption of 10 to 30 milliseconds will not cause a clinical issue because the device’s internal circuitry bridges short gaps. But some sensitive equipment may restart or alarm.

Stations in our database with published UPS switchover times include the Zendure SuperBase V4600 (1ms on US model 5-20 outlets), the Anker SOLIX C1000 (20ms), the Bluetti AC180 (20ms), and the EcoFlow RIVER 2 (30ms).

Keep the battery charged. Maintain your power station above 80% charge at all times. LFP (lithium iron phosphate) batteries handle long-term float charging well. Set a weekly reminder to check the charge level.

Label everything. Attach a label to your power station with: the medical device it is for, the device’s wattage, and the expected runtime. In an emergency, a family member or caregiver who has never used the setup should be able to plug in and go.

Minimum evidence to trust your plan

Your backup plan is only as reliable as your worst test. Before you consider your setup ready, confirm all five of these:

You have run your medical device on battery power (not wall power through the station) for at least 30 minutes.
You have tested with the battery at 30 to 40% charge, not just at 100% — some inverters behave differently at low state of charge.
You used the actual cable, extension cord, and outlet configuration you plan to use during an outage. Not a shorter test cable.
You know what triggers your device’s alarms (low power, power interruption, low pressure) and how to silence or respond to each one.
You have recorded the observed runtime and compared it to your calculated estimate.

If any of these five tests reveals a problem, resolve it now. Discovering a compatibility issue during a real outage is not a test — it is a failure.

Step 5: Emergency Contacts and Plan B

Battery backup is one layer. You need at least two more.

Register with your electric utility

Most US utilities maintain a medical baseline or life-support registry. Being on this list does not guarantee faster restoration, but it flags your address for priority consideration during planned and unplanned outages. Contact your utility’s customer service line and ask about their medical equipment program.

Keep backup oxygen tanks

If you use an oxygen concentrator, maintain a supply of compressed oxygen tanks as your last-resort backup. The American Lung Association recommends keeping “a large backup metal tank” — an E-cylinder provides approximately 5 to 6 hours at 2 LPM continuous flow. FEMA’s ready.gov guidance recommends planning for at least 72 hours of backup supplies for any life-sustaining need. Your HME provider can arrange delivery and help determine the right number of tanks for your prescribed flow rate.

Build redundancy into your power plan

A single battery is a single point of failure. For life-critical equipment, consider layering your backup:

Second battery or expansion pack. Two smaller power stations may be more resilient than one large unit. If one fails, you still have the other.
12V DC power. Many CPAP machines accept 12V or 24V DC input directly, bypassing the inverter entirely. DC-to-DC power is more efficient than AC and extends battery runtime by roughly 20 to 30%. Check your device manual for a DC input option.
Vehicle charging. Your car battery can recharge a power station via a 12V car port or charge some medical devices directly. Keep the appropriate cable in your emergency kit. Run the vehicle engine in a well-ventilated area (never in a garage).
Portable generator with transfer switch. For stationary oxygen concentrators or multi-device households, a fuel-powered generator installed by a licensed electrician with a transfer switch provides days of runtime that no battery can match. This is the highest-cost option but also the most capable for extended outages.

Identify a Plan B location

Know at least one location with reliable backup power where you can go if your battery runs out: a hospital, fire station, community shelter with a generator, or a family member’s home. Know the route, the travel time, and whether the location can accommodate your equipment. Keep a portable concentrator or backup oxygen tank ready for transport. If your area faces fire-season evacuations, review our wildfire evacuation power kit guide and pre-pack your critical medical power gear.

Emergency contacts checklist

Keep this list printed and posted near your medical equipment:

911 — if your device fails and you cannot restore power
Physician after-hours line — for clinical guidance during extended outages
HME provider — for emergency equipment delivery or oxygen tank refills
Electric utility medical priority line — to report an outage affecting medical equipment
Local emergency management office — for shelter locations with generator power
Neighbor or family member with a generator — as an immediate backup option

Know the HHS emPOWER program

The Department of Health and Human Services maintains the emPOWER Map, which tracks over 4.6 million Medicare beneficiaries who depend on electricity-powered medical equipment. While the program works through public health agencies rather than individual registration, awareness of it helps you advocate for services in your area during disasters.