CPAP Camping in Cold Weather: How to Keep Your Battery Working on Fall Trips

Yes, you can run your CPAP on a battery through a cold fall night. The EXP48PRO APEX will keep powering your machine when the temperature drops. What changes is how much you get out of each charge, and when you're allowed to recharge. Cold reduces the energy a battery can deliver, and the EXP48PRO APEX, a lithium iron phosphate (LiFePO4) battery, should never be charged below 32°F. Plan around those two facts: keep the battery with you in the shelter and off the cold ground, charge it when it's above freezing, and count on the low end of your runtime estimate. Do that and cold-weather CPAP camping is very manageable.

Here's how that plays out in a tent, a van, a truck bed or a hunting camp.

What cold actually does to your CPAP battery

Every battery delivers less when it's cold. The chemistry inside slows down, so the same battery that gave you a comfortable margin in July can come up shorter on a 30-something-degree night in October. Nothing is broken. You're just drawing from a smaller effective tank.

Two rules matter most for the EXP48PRO APEX:

• Running your CPAP in the cold is fine; expect less runtime. Ambient temperature is one of the things that affects how long your battery lasts, along with your CPAP pressure and mode, your machine model, humidifier and heated-hose use, mask seal and the battery's age.
• Charging has a hard floor. Don't charge below 32°F. The optimum ambient range for charging is 40°F to 110°F. On the other end, the battery should never go above 120°F while charging or running.

So the battery keeps working in the cold, but it won't give you everything it gives you on a mild night. For more on how heat and cold affect lithium batteries in general, see How Does Temperature Affect My Battery?

Plan your nights with the low end of the estimate

The EXP48PRO APEX is a 153.6 Wh LiFePO4 battery. With the humidifier and heated hose turned off, it's estimated to run a CPAP for 2 to 3 nights on a single charge. That's always an estimate, and in cold weather you should plan on the lower end of it.

A practical way to plan a fall trip:

• Count on 2 nights per charge, not 3. If you end up with a third, that's a bonus.
• Check the LCD every morning. The screen shows your battery percentage. Note the number each day so you can see your real usage on this trip, with your machine and this weather.
• Plan a charge before you need one. If the morning reading tells you tonight will be tight, use today's drive or today's midday sun to top up.

Your own numbers will depend on your machine and pressure. For a full breakdown of what drives runtime, read How Long Will a CPAP Run on a Battery?

The humidifier question on cold, dry nights

Here's the tradeoff that surprises people in the fall. Cold air is dry, and it's exactly when you might want your humidifier. But the humidifier and heated hose are large power draws. That's physics, not a battery flaw: heating water and heating a hose takes a lot of energy.

The 2 to 3 night estimate for the EXP48PRO APEX assumes both are off. If you need them on, you'll use your battery much faster. Here's how to handle it:

• Turn them off for battery nights. Here's our step-by-step guide to turning off the heated hose and humidifier on your CPAP.
• Ask about a heat moisture exchanger. An HME is a small passive device that many CPAP users ask about for comfort when the humidifier is off. Talk to your equipment provider or sleep provider about whether one fits your setup. Our overview explains what an HME is and why you might consider one.
• Size up if the humidifier has to stay on. The EXP96PRO APEX holds 307.2 Wh. It's estimated at 4 to 6 nights with the humidifier and heated hose off, and roughly 1 night with both on. For drive-in camps where weight isn't the issue, it's the better fit for heavy use.

Any questions about your therapy comfort or settings belong with your sleep provider. Your battery plan should work around whatever setup they recommend.

Keep the battery with you and off the cold ground

Where the battery spends the night matters more than almost anything else you can control. Cold ground pulls heat out of whatever sits on it, fast.

In a tent: Keep the battery inside the tent with you, not in the vestibule. Set it on your sleeping pad, a folded jacket or a closed-cell foam scrap rather than directly on the tent floor. Keeping it in the gear bag also adds a layer between the battery and the ground.

In a van or SUV: Keep it in the living space where you sleep, not against an exterior wall or on a bare metal floor. A rug, a pad or a seat cushion under it helps.

In a truck bed or camper shell: Keep the battery up on your sleeping platform or pad, not in a toolbox or on the bed liner. If you're sleeping in the cab, bring it in with you.

At hunting camp: Keep the battery in the tent or wall tent with you overnight. Don't leave it in the truck while you're out before first light, then expect it to be ready to charge the minute you get back.

Two more habits help:

• Keep it dry. Frost, dew, snow and condensation all count. Never expose the battery to liquids. If it's been sitting in cold air and you move it somewhere warm, let it warm up and wipe off any moisture before you connect anything.
• Run a short, direct setup. Plug your CPAP DC cord straight into the battery's DC port and keep the cable run tidy so nobody kicks it loose in a cramped tent.

Charging when temperatures are near freezing

This is where fall trips take some thought. The rule is simple: do not charge the EXP48PRO APEX below 32°F. Charging does best between 40°F and 110°F.

On a trip with frosty mornings, that means you charge during the warm part of the day, not at dawn.

Charge on the drive. The DC car charger fills an EXP48PRO APEX in about 4 hours. With the cab heater running, you're comfortably in the right temperature range. If you're driving between campsites, into town or out to your hunting spot, that's charging time.

Charge midday on solar. The Summit 60W solar panel charges the EXP48PRO APEX in under about 5 hours. Fall sun sits lower and the days are shorter, so give the panel the full middle of the day and aim it at the sun. Put the panel in the sun and keep the battery in the shade. For help choosing a panel, see 60W vs 100W Portable Solar Panels.

Charge on AC when you have it. A campground outlet, a lodge or a friend's cabin gets you a full charge on the AC wall charger in about 2.5 hours.

Bring it to room temperature first. If the battery spent the night in a cold truck, let it warm up in the heated cab or indoors before you plug it in. Don't start charging a cold-soaked battery just because the air around it has warmed up.

And the safety basics apply every time: never charge a battery that's visibly damaged or bulging.

Longer cold trips: two batteries or a bigger one

If you're out for a long weekend or more with limited charging, you have two good options.

Two EXP48PRO APEX batteries. You can connect two EXP48PRO APEX batteries in parallel, no more than two, using the DC method in the user manual. That doubles your capacity while keeping each battery light enough to carry. Don't chain them through USB-C. Many people simply run one battery per night and keep the second charged and ready.

One EXP96PRO APEX. At about 6.5 lb, it's a drive-in camp battery, not a backpacking one. It has two DC output ports, so it can power two CPAP machines at once, and it's rated IP65 for dust and low-pressure water jets. It's not submersible, so still keep it dry. The EXP96PRO APEX is not airline-eligible, so if your fall trip starts with a flight, the EXP48PRO APEX is the one to pack.

Your cold-weather CPAP camping checklist

Before you leave:

• Check your cord. CPAP DC cords are specific to your CPAP model, not the battery. The most common mistake is the wrong generation, like a ResMed AirSense 10 cord for an AirSense 11. Test the full setup at home.
• Charge fully at home in a warm room.
• Set your CPAP up for battery nights, with the humidifier and heated hose off, and ask your provider about an HME if you want one.
• Pack a way to charge: DC car charger, Summit solar panel or AC charger.
• Pack something to set the battery on: a foam pad scrap works well.

At camp:

• Keep the battery in the shelter with you, off the ground.
• Check the percentage on the LCD every morning.
• Charge on the drive or at midday, only when the battery is above 32°F.
• Keep it dry and let it warm up before charging.

For the rest of your camping prep, read our Top 10 Things to Know Before Going Camping With a CPAP Machine.

Storing your battery at the end of the season

When the last trip of the year is done, set the battery up for the off-season. If you're storing it for more than 3 months, charge or discharge it to 40 to 50% and keep it in a cool, dry place. Recharge it at least once every 3 months while it's in storage. That's required to keep your warranty valid, and it keeps the battery healthy for spring. More tips are in Maximizing the Lifespan of Your Lithium Iron Phosphate Batteries.

Go enjoy the cold nights

Fall is some of the best camping of the year. The crowds thin out, the bugs are gone, and a clear, cold night in the tent is hard to beat. Your CPAP can come along. Keep the battery with you, charge it when it's above freezing, and plan with a margin.

Find the right battery for your CPAP: Shop the EXP48PRO APEX, bundled with the CPAP DC cord for your machine.

Frequently asked questions

Can I use my CPAP battery below freezing?

Yes. You can run your CPAP from the EXP48PRO APEX on a cold night. Expect less runtime than on a mild night, and plan with the low end of the 2 to 3 night estimate. What you can't do is charge it below 32°F.

Why won't my battery last as long when it's cold?

Cold slows the chemistry inside any battery, so it delivers less usable energy. Keeping the battery inside your shelter and off the cold ground helps. Humidifier and heated-hose use have an even bigger effect on runtime.

Can I use my humidifier while camping in cold weather?

You can, but it uses much more power. The EXP48PRO APEX estimate of 2 to 3 nights assumes the humidifier and heated hose are off. If you need them on, the EXP96PRO APEX is estimated at roughly 1 night with both on. Some people ask their equipment or sleep provider about a heat moisture exchanger (HME) for comfort with the humidifier off.

How do I charge my CPAP battery on a cold camping trip?

Charge when the battery is above 32°F, ideally in the 40°F to 110°F range. Use the DC car charger while you drive, a Summit solar panel at midday, or AC power when you have it. If the battery has been cold overnight, let it warm to room temperature first.

Should I keep my CPAP battery in the car overnight?

Keep it where you sleep. Whether that's a tent, a van or a truck cab, the battery belongs in the shelter with you and up off the cold ground or floor.