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.
Follow Dave’s RV adventures as he travels the West in search of forgotten and unique places. For Dave, home is where you park it, the more remote the better!