How long will a battery run a CPAP machine?
Pick what you own and what you need to keep on. No watt-hours, no amp-hours, no math.
A CPAP machine draws about 40 watts on average and needs roughly 60 watts for a moment when it starts. A 293 Wh power station such as a Jackery Explorer 300 holds about 237 usable watt-hours after inverter losses, so it would run one for 5 hr 55 min. Most CPAP units draw 30 to 60 W with the humidifier and heated hose switched off. Those two are heating elements, so leaving them on roughly doubles the figure.
293 Wh · 300 W continuous · tap to change
Anything else on it?
3 hr 9 min
Jackery Explorer 300, running cpap machine, two phones charging, wifi router + modem.
The other half of the answer
That is one appliance. How many days of power do you actually have?
Most homes have no emergency source of power when they need it. Provision Planner keeps track of the power you have and helps you build it up before you need it.
About 2 minutes.
What would actually change this
| If you had | Runtime | Starts it |
|---|---|---|
| What you have now | 3 hr 9 min | Yes |
| A second Jackery Explorer 300 | 6 hr 19 min | Yes |
| A Bluetti AC180 insteadcarries it overnight | 12 hours | Yes |
| Any of the above, plus solar | Indefinite, sun allowing | Unchanged |
Solar is the only row that puts energy back in. The rest just start the outage with more of it.
What this assumes
- Most CPAP units draw 30 to 60 W with the humidifier and heated hose switched off. Those two are heating elements, so leaving them on roughly doubles the figure.
- 85% inverter efficiency, and 95% of the 293 Wh on the label as genuinely usable, which gives 237 Wh to spend.
- Your own appliance, your climate and how often the door opens will all move this. It is a close estimate, not a promise.
About CPAP machines specifically
The blower is a small motor and draws very little. The humidifier and the heated hose are heating elements, which is where almost all of the watts go. A higher pressure setting also makes the blower work harder. For your own unit, the power supply label gives a figure no average can match.
Before the next outage
Most homes have about three days of food and water in them.
Provision Planner counts yours and tells you the number: days of food and water covered for your household, what expires when, and what to buy next. Your power is one line in it.
About 2 minutes. Nothing to install.
Read it off the brick, not off a chart
Every one of these ships with an external power supply, and the label on that brick states its output: a voltage and an amp figure, commonly 24 V and somewhere between 1.5 and 3.75 A. Multiply the two and you have the ceiling in watts for your exact model, which is worth more than any average on any website including this one. A 24 V 2.5 A supply tops out at 60 W, and the machine spends most of the night well under that.
Skip the inverter and you gain about an hour
Most of these accept DC directly through a 12 V cord sold by the manufacturer, and plugging into the DC socket on a power station rather than its mains outlet skips the inverter altogether. That is roughly 15 percent of the pack you stop burning as heat. Many power stations also idle a few watts just keeping the AC side awake, which matters over eight unattended hours in a way it never does over twenty minutes.
Count in nights, not in hours
A runtime of eleven hours and a runtime of seven hours sound similar and are not: one covers a night with room to spare and the other stops before morning. Eight hours is the figure worth planning against, and it is the reason the humidifier question below decides so much. Charging the pack to full the evening a storm is forecast is the cheapest thing on this page.
| Setting | Typical draw | On a 293 Wh power station |
|---|---|---|
| Humidifier and heated hose off | about 40 W | 5 hr 55 min |
| Humidifier on, hose off | about 65 W | 3 hr 39 min |
| Humidifier and heated hose on | about 90 W | 2 hr 38 min |
Same machine, same battery, three different nights. Running on DC rather than through the inverter adds roughly 15 percent to each figure.
The 5 people ask about most
Provision Planner
See exactly where your household stands.
Provision Planner counts what is already in your house and tells you how many days of food, water and power it covers for the people who live there, what expires next, and what to buy this month.
See how long my preps will lastAbout 2 minutes. Nothing to install.
The next questions, answered
Can a CPAP machine run off a battery overnight?
The arithmetic is straightforward. With the humidifier and heated hose switched off a typical unit averages around 40 watts, so a 293 Wh power station delivering about 237 usable watt-hours through its inverter covers roughly 5 hours 55 minutes, and the same pack used through its DC socket covers closer to 7 hours. Switch the humidifier on and the draw roughly doubles, which halves both figures. Your own machine's power supply label gives the ceiling for your model, and the manufacturer's documentation covers which batteries they support.
Why does the humidifier change the number so much?
Because it is a heating element rather than a motor. The blower that moves the air is small and cheap to run; the heater plate that warms the water, and the wire running down a heated hose, turn electricity straight into warmth at about one watt for one watt. That is the same reason a kettle empties a power station in minutes while a router runs for days.
Is it better to use the DC socket or the mains outlet on a power station?
DC, where the manufacturer sells a cord for it. Converting the pack's stored DC up to household AC and back down again inside the machine's power supply wastes roughly 15 percent as heat, and the inverter itself draws a few watts simply being switched on. Over a single night that difference is worth most of an hour.
How long will a battery run a CPAP machine?
A CPAP machine draws about 40 watts on average and needs roughly 60 watts momentarily to start. On a 293 Wh power station with about 237 usable watt-hours, that is about 5 hr 55 min. Most CPAP units draw 30 to 60 W with the humidifier and heated hose switched off. Those two are heating elements, so leaving them on roughly doubles the figure.
How long will a battery last running a refrigerator?
A 293 Wh power station such as a Jackery Explorer 300 delivers about 237 usable watt-hours after inverter losses. A full-size refrigerator averages about 50 watts because the compressor cycles roughly a third of the time, so the runtime is around 4 hr 44 min. The catch is start-up: a compressor needs roughly 800 watts for a fraction of a second to kick on, and a unit that surges to only 600 watts will not start it at all.
Why is my battery's real capacity lower than the label?
Two losses. Converting stored DC into household AC costs about 15 percent as heat, and not all of the stored energy is safely usable: lithium power stations give up roughly 95 percent, lead-acid deep-cycle batteries about half, and a car starting battery only about a third, because you still need it to start the car.
What drains a portable power station fastest?
Anything that makes heat. Space heaters, kettles, hair dryers and microwaves convert electricity to warmth about one watt for one watt, so a 1500 watt heater empties a 293 Wh power station in roughly ten minutes. Motors come second because starting them costs several times what running them does. Lights, routers and phone charging are negligible by comparison.
How many days of power does my whole household have?
One battery and one appliance is the easy question. The harder one is everything at once: the lanterns, the spare cells in a drawer, the power bank nobody has charged since spring. Provision Planner counts what is already in the house and turns it into days of light and power for the people who live there, alongside days of food and water, then names the cheapest thing that would add the most.
Can a portable power station run a space heater?
In practice, no. A 1500 watt space heater draws its full rating continuously, which exceeds the continuous output of most portable power stations and would empty even a large one within the hour. Warmth in an outage comes from insulation, layers, and shutting the doors on one room you all sit in.
Battery figures come from manufacturer specs for 45 models across Jackery, EcoFlow, Goal Zero, Anker and Bluetti, plus generic car and deep-cycle setups. Where a brand advertises a boosted output mode, we use the lower rating. Appliance draws are typical household figures, shown on the page with the reasoning behind them rather than buried. If the power is out right now, the live power outage map shows what is reported near you, and how long a freezer stays cold without power covers the food side. Wondering whether you could refill a battery yourself? Work out how many months of the year solar would cover you.
About medical devices. These figures are planning estimates, not medical advice, and nothing here should replace guidance from your doctor or your equipment supplier. If anyone in your house relies on a CPAP, an oxygen concentrator or any other powered medical device, confirm the power requirements in that manufacturer's own documentation and arrange backup power with them. Do not use this page to decide whether a device will keep someone safe.