As a portable power guy, I get asked quite frequently about powering CPAP & BiPAP machines while camping. My former business partner uses a ventilator in managing his Duchenne's Muscular Dystrophy, so this application is important to me.
First Things First… What is a Watt?
It's difficult to have any discussion of electricity without some basic math. But, I will try to keep it to a minimum. All you really need to know is that I have done some calculations to know how fast your CPAP or BiPAP machine will be taking power out of a battery pack, so that I can estimate how many hours you can operate your machine while camping away from a power source before the battery needs to be recharged.
Powering the Machine…
What I have found in my research, is that a typical machine (Respironics, ResMed, and the like), will draw between 20 & 30 Watts (2-2.5Amps) when not using the humidifier. What this means is that you can use fairly standard battery packs to support your machine through several nights out in a tent.
For example, I have had clients use a battery pack with 150 Watt-Hour capacity to get a full night's sleep of 8 hours with plenty of room to spare. Others have been able to get two 6-hour nights using stingy CPAP machine settings.
Here are a few battery pack options to consider…
Brunton Impel : 145 Watt-Hours : 1-2 nights
Novuscell C150 : 150 Watt-Hours : 1-2 nights
Novuscell C220 : 220 Watt-Hours : 2-3 nights
100 AHr 12V Deep Cycle : 600 Watt-Hours : 3-4 nights
Most CPAP & BiPAP machines either come with a car adaptor, or have one available as an option from the manufacturer. This is a key piece of equipment, because all battery packs are DC, and this "CLA" connector will let you plug your CPAP into the battery pack exactly as you would plug it into the dashboard of your car. All the battery packs listed above come equipped with this 'CLA' socket just like in your car, and are plug-n-play with your CPAP machine.
Can you use AC power if you want? It can be done, but it is NOT recommended for several reasons. First, inverters waste 20-30% of your battery power in making AC power which your CPAP will be turning back into DC power anyway. So don't waste this power if you don't need to... use the DC car plug for your CPAP. Secondly, most Lithium batteries do not support AC inverters. The Novuscell models listed above are able to handle small 200W inverters, but save them the stress and stick to DC. Lastly, using an inverter just adds one more piece of equipment to carry, so use only when necessary.
One of the most important aspects of camping is to be able to go into remote areas. To do this comfortably means NOT packing anything too heavy, so it becomes a balancing act between weight and the amount of power you need each night.
The lightest battery packs are lithium-based, such as the Brunton Impel, and Novuscell models listed above. In a battery that weighs only 2-4 pounds, you can store enough power for up to 3 nights.
Recharging In The Wild…
What do you do if you need more than 1-2 nights' support for your CPAP or BiPAP machine?
In the absence of a vehicle to act as a generator for recharging your CPAP camping battery, one of the most logical solutions is to use portable solar panels. For example, a 20 Watt panel will offset approx 50% of your CPAP power usage, while a 60 Watt panel will completely replace the power you use each night.
Here are a few examples of such panels (smallest I would recommend). I have selected the panels that perform best in partial shade (ie under trees), and in low-light conditions (ie overcast), because you never know what you might get out there…
Powerfilm R-21 : Waterproof, rollable, tough
Solaris 26 : Folding efficiency
Powerfilm 20 : Folding sensitivity (the lightest option)
Affording A Portable Power System…
At this point, you might be thinking that these products are rather expensive for someone who might only be going camping with their CPAP or BiPAP machine a couple of times each summer. To help, Modern Outpost has introduced a power system rental program. Now you can save the expense of owning a portable solar power system, and be sure of getting the latest & greatest equipment for supporting your CPAP while camping.
I hope this helps.
If you have any comments, questions, suggestions, or experience that will add to this discussion, please share it with us.