In preparation for a motorcycle camping trip, I had some new considerations to accommodate my recent diagnosis of Sleep Apnea.
It had been awhile since I last went backpacking and a thorough inventory of my equipment was a must. Proper storage, good equipment and care has kept my equipment in nice condition over the past 8 years. Digging through my camping storage bin revealed most all the equipment I would need. Much of what I found in that bin will cover most of my needs however, being recently diagnosed with Sleep Apnea has put some constraints on the sleeping freedom I had taken for granted.
Every night since my Sleep Apnea diagnosis I have had a ResMed S9 Auto CPAP machine clung to my face like an alien face hugger from the movie Alien. With a sleep dependency as my top concern, finding an alternative power source that could run my CPAP machine while I slept at night was my top priority.
While my riding group were still in the trip planning phase, I stopped into my local medical supplier to acquire a power adapter and battery that would give me some independence from the AC power outlet I'm currently chained to. Unfortunately, the medical supplier had only the necessary attachments to run my CPAP machine from a 12-volt power source but not a 12v battery.
The accessories I was given had some large alligator clips to attach to the terminals on a 12 or 24-volt battery. On the other end of the clips was a car lighter receptacle. The power supply provided for the CPAP machine had a male car socket that attached to the receptacle leading from the battery. My next problem was finding a battery that was light enough to carry on the motorcycle and backpacking, durable, and could power a the machine for a a minimum of 8 hours.
Several options came to mind ranging from RC battery packs, car batteries, even power wheel batteries. After doing a bit of research I decided the best option would be an Absorption Glass Mat battery. An AGM would provide the benefits of a deep cycle battery while keeping the battery light and leak free.
|MagnaPower AGM Battery with ResMed Power Supply|
Stopping into the local auto part store, I found was a small 12-volt ATV battery with 180 cold cranking amps which would provide a 10amp hour run time. Produced by MagnaPower. Sealed and rugged, these batteries can take a beating and can out perform a deep cycle battery on discharge and charging. The price of the battery was around $75.
Eager as I am to try new things, I attached the accessories to the battery and ran my CPAP machine for 1 night at home. When I woke the next morning the machine was still running. The battery came pre-charged with a voltage reading of 12.45v. After running the CPAP for 7 hours from the better the voltage indicated 11.45v. Given that the machine was still running I would presume that at a certain voltage the power supply will cut off.
Unpacking and assembling the CPAP machine was a breeze. At night I protected the battery leads, using the box, just in case I kicked the battery over in my sleep. The machine ran a full 6-8 hours and in the morning I was able to charge my phone from it as well.
More recently I've been doing research on this particular battery and the power consumption of the CPAP machine. ResMed provides a nice guide that explores each model, the amp draw at different power settings and a recommendation for the size of battery. According to the chart I would need to use a 12 amp hours per 8 hours of continuous power and ruining a treatment pressure of 10 on my ResMed S9 Auto CPAP. Here is a link to ResMed's Battery Guide.
Though this battery worked for a single night, a daily charging solution will need to be considered. I will be looking into a solar charging option that will also work as a tender for the battery. The solar charging option will give me the ability to charge during the day with out the need to tap into my alternator and risk over taxing it. Overall though, I would recommend purchasing a larger battery that at minimum would last 2 days or if weight isn't a concern, a more traditional sized battery.