Is Boondocking Safe with a CPAP Device?
I am often told, “I would like to boondock, but I / my husband uses a CPAP machine.”
I suspect most CPAP users started using their machines at home and are accustomed to plugging them into a standard wall outlet in their house. However, when you are boondocking/dry camping with a CPAP machine, the wall (120 VAC) outlets in the RV aren’t energized unless you have a built-in inverter or are running a generator.
But here’s the problem: Inverters are inefficient and can use up the house batteries quickly. Besides, who wants to listen to their generator run all night? (Note: your neighbors don’t want to, either.)
Instructions for Dry Camping with a CPAP Machine
While I am not a CPAP user myself, the male half of our friends who travel with us (and love to boondock) does and the following are some things I have learned from him and others.
Running a CPAP machine on 12-volt power
Most CPAP machines operate on low DC voltage like 12 volts, so when you plug them into a 120-volt wall outlet, a transformer in the CPAP steps the voltage down to what the machine needs to operate. So, the first thing you want to do is skip the inverter and power the CPAP directly from the “house” batteries in your RV.
It’s worth noting that not only is an inverter an inefficient way to power a CPAP, but stand-alone inverters are likely to drop out or quit operating when they sense a voltage drop, which is very likely to happen when the furnace in your RV cycles on and off during the night.
If your CPAP did not come with a 12-volt adapter allowing it to operate via 12-volt power, you can likely find one online that fits your machine, such as this one. If you can’t find a 12-volt adapter for your CPAP, you will have to use an inverter. When that happens, obtain one rated for slightly more than the needs of your machine. Consider connecting it to a stand-alone battery (outlined below). This provides a stable voltage source.
Use a portable battery
The next item to consider is adding a battery just for CPAP power. It can be a portable battery designed to be taken anywhere. Even better, and likely less expensive is to add a deep-cycle marine battery. Located it near the sleeping area. This is convenient, but can be mounted elsewhere in the RV too. Use a dedicated 12-volt outlet next to your bed/nightstand.
Wire the battery into the RV’s charging system. Your goal is to ensure it receives a charge when power (shore power, generator, or solar) is coming into the unit. But is needs a method to isolate it from the house batteries when charging isn’t occurring.
How much power do you need?
Finally, do some math. Calculate how long the battery charge will power your CPAP before it will require recharging. Take a volt ohm meter. Then measure the amount of amps needed to operate the CPAP. Do it with the humidifier on and turned off via 12 volts. Then divide the required amps by the usable amp hour reserve in the battery. This determines the duration of run time in hours.
In my friend’s case, he runs his CPAP with the humidifier turned off. This requires less than 2 amps per hour to operate. That way he can go days without recharging the deep-cycle battery supplying power to his CPAP. If the battery is located anywhere within the RV (including exterior baggage compartments), it must be contained in a sealed battery box. The box must be vented to the outside or the equivalent to prevent gasses from entering the living space of the RV.
Typically, you can count on 50% of the rated capacity of a lead acid battery. And you can count on nearly 100% of a lithium battery. Let’s say you have a deep-cycle marine battery labeled with 100 amp hour reserve. You can expect to extract 50 usable amp hours from the battery.
Hopefully these tips will help CPAP users break free from the shore power tether.. They can begin experiencing the freedom of camping in the boondocks. Many adventures in RVing are found there.
For more ways to power a CPAP machine in an RV, motorhome, camper, boat, or tent, check out this helpful video from RV Vagabond Jerry:
RVers looking for valuable how-to information have learned to go to the experts. Forums such as iRV2.com and blog sites like RV LIFE, Do It Yourself RV, and Camper Report provide all the information you need to enjoy your RV. You’ll also find brand-specific information on additional forums like Air Forums, Forest River Forums, and Jayco Owners Forum.
Dave Helgeson’s many roles in the RV industry started before he even had a driver’s license. His grandparents and father owned an RV dealership before the term “RV” had been coined, and Dave played a pivotal role in nearly every position of an RV dealership. He and his wife Cheri launched their own RV dealership in the Pacific Northwest. The duo also spent 29 years overseeing regional RV shows. Dave has also served as President of a local chapter of the Recreational Vehicle Dealers Association (RVDA), worked on the board of advisors for the RV Technician Program of a local technical college, and served as a board member of the Manufactured Home and RV Association. Dave’s reputation earned him the title of “The foremost expert on boondocking,” bestowed by RV industry icon, the late Gary Bunzer (The RV Doctor). When he’s not out boondocking, you’ll find Dave in the spotlight at RV shows across the country, giving seminars about all things RVing. He and Cheri currently roam in their fifth travel trailer, with Dave doing all the service, repair and modifications to his own unit.
JAMES GEER says
Our Resmed CPAP machines run from 24VDC. I did an experiment and found that their dedicated 12V boost power supply was much more efficient than running an inverter and the std AC power supply.
K Langdon says
I use MAXOAK Lithium Portable Power Station by BLUETTI. I can get 3-4 days use and charge an i-pad or phone as well.
Will Belden says
Sometimes these are what you might need. (They come in different sizes.)
I used these to eliminate the need for plug adapters for some networking setups in our rig. It IS important to have an inline fuse, though, to protect your system.
I bought this years ago for a different purpose, but have hung onto it and it works well for a multi-component wiring project.
…but you can get a simple inline fuse at any almost any auto parts store, or these: https://smile.amazon.com/gp/product/B01FOEFYYS/
One last note, and the author’s information does remove the problem, but to be clear, not only are inverters inefficient, but using it in this scenario means you’re going from DC… to AC…. back to DC. Cutting out the middleman minimizes overall power loss, to be sure.
Ron Cadenhead says
Since you only have access to your friend’s information about his CPAP, there are a lot of us out here feeling left out. We are the ones using 24v ResMed CPAPs. It just hit my thoughts while writing this, that perhaps with the humidifier turned off the 24v models may run on 12v. Any ideas about that question?
I have 4 large 6v batteries connected to provide 12v to my trailer. I use solar to recharge the batteries. Is there a way to wire a second set of wires to provide 24v to my CPAP while the main large wiring still provides high amperage 12v to my trailer and inverter?
Do you know of any other way to power a 24v CPAP?
Thank you for your time,
David Gilmore says
My wife has the same CPAP. I think the best option for you is simply purchase an inverter to go from 12VDC to 120VAC.
I think a basic 200 watt inverter should be fine, provided you have 12 volts near your CPAP.
You’d need to really understand your camper battery setup to add a battery to get 24 volts. My guess is that you have 2 – sets of 6 volt batteries in series, and those 2 sets are in parallel with each other to get 12 volts. It could be done, but not worth the hassle.
I wish you success in you endeavor. Dave
My husband uses a bipap machine and we have a van that has been converted into a camper
He bought a deep cell battery, has it wired to the main battery so when the van is running we are charging both batteries. When we stop he turns it off and has a 12 volt charger to plug into and we can/do go everywhere our van will take us!!
Brian Clancy says
What is your actual model number? That’s how they are matched up. I have a Resmed AirSense 10 that runs on 12v but the converter is 19v, it runs fine. Works or AirSense or AirCurve, both. This is the standard converter Resmed dealers offer, called the Resmed 37297 Air10 DC-DC Converter, $55 on Amazon.
Ron Cadenhead says
Bryan Clancy. Thank you for your solution. That converter is just what I need rather than use my inverter 110v output. I have the Resmed AirSense 10 and will order the converter.
Bob Kannitzer says
I have a CPAP and I power it through a 12 volt outlet that runs to a converter that transforms 12 volt to 120vac and runs my CPAP. I have 2 12 volt outlets in my Motorhome, 1 in front of the passenger seat and another 1 under the desk in the bedroom.
George Miler says
Just buy an AGM or Lithium batterie and all will be just fine. George Miller
Good article. Some things I noticed. Lithium will usually drop off after about 80% use but still that’s a lot more than lead acid. If one has 50 usable amps then a 2ah cpap will last about 25 hrs or roughly three 8hr nights. Something to take into consideration if going on a five day trip. And those small book sized lithium units that people think work good for their lapsotps are often 2-3 amps. That relates to 1-2 hours of use for a cpap.
I use a Jackary 293wh portable power pack. It will power 2 CPAP machines, without the humidifier and heated tube, for 8 hours plus charge 2 cell phones. It can be connected to optional solar cells, charged by your vehicle, or plugged in to a generator during the day so as not to make too much noise at night. Takes about 4 hours to recharge.
Doug Grimes says
I was able to purchase a 12v adapter for my cpap and also mount a 12v lighter socket near the nightstand area (both off Amazon). My RV has 12v lamps on either side of the bed that I was able to tap into for power (the lamps aren’t on during sleeping hours…).
As a long time CPAP user, I can relate to the need to have power for your CPP, BUT…as a matter of health and safety, you should NEVER have a battery inside the RV living area, especially near the bed, which is often in a closed off room for privacy. Why? When a battery is charging or discharging, it will give of gases that can be extremely dangerous to inhale, and even more, those same gases are extremely EXPLOSIVE, with only the smallest of sparks. (haven’t you ever heard of a battery exploding when connecting jumper cables????)
adding a 12 volt socket that is directly wired to the house battery is the second safest way to power your device, but for safety sake please include and “inline” fuse just in case of electrical short or other failure of your device. So what is the best option? Most CPAP companies make dedicated rechargeable power packs, and extension hoses for the mask….thus you can have the blower located safely away from the sleeping are, and not have to run any wiring or install extra outlets
A 24V CPAP will still require 24V with the humidifier turned off. It will require fewer amps, and therefore your battery will last longer whether you’re using a 12V to 24V converter or inverter for 120V AC.