Tent Camping

Hello friends,
I am an aerospace engineer under a doctor’s care for severe OSA but that has not kept me from tent camping each year. I would like to share with you my experience and knowledge so that maybe one day you can also enjoy the great outdoors in a tent. For the purpose of this post I will only reference my ResMed S9 Auto CPAP, H5i humifier, heated hose and a Swift nasal mask. The principle of using a portable 12VDC supply would apply to most CPAP equipment and I would recommend a little research before you spend any money. I typically camp for 3-4 nights and power my equipment with a ResMed R360-792 power inverter (comes with a battery adapter) and a 115 amp hour deep cycle battery. I have used this system for 7-8 hours each night without requiring a charge. Obviously you should fully charge the battery before your trip and having a portable trickle charger (cigarette lighter or solar) would be a good addition. Now for the downside of tent camping with a CPAP. In the late night and early morning hours the temperatures drop and the heated humidifier and hose do not work correctly when exposed to cold. I tried pushing my hose in my sleeping bag and covering my CPAP with a blanket but I ended up without a good night sleep. The next camping year I bought a Coleman Sport Cat portable tent heater and the problem was solved. This is a pretty generic type of set up and I wanted to write a post that was not too technical or discouraging. Oh, a charged deep cycle battery and power inverter is a great addition for your emergency preparedness kit if the power goes out!
Happy Camping

A good post but I must add one more point: Powering a CPAP through an inverter is usually only 60-70% efficient. Resmed offers a DC/DC converter that raises the voltage from 12 to 24 volts, which (I'm guessing) is more like 90%. Respironics is 12v powered so their DC cord is 100% efficient. Avoiding the inverter will translate into less power needed. This means more time on the battery, longer battery life, or a smaller battery.

While that is true...

The inverter will warm up and that may be welcome during a chilly night.

Good information here and a more efficient system with an extra set of clothes is most likely lighter than carrying a bigger battery.

Hi there, going camping soon and I have a question that relates to remaining battery charge and treatment pressure.

I have a ResMed S9, a ResMed DC/DC converter and a fully-charged Optima boat battery.

My question is this: as the battery loses power with each night, will the treatment pressure (strength of blowing air) decline slowly or will the converter/S9 suddenly stop when it no longer has the minimum power?

maviduya wrote:Hi there, going camping soon and I have a question that relates to remaining battery charge and treatment pressure.

I have a ResMed S9, a ResMed DC/DC converter and a fully-charged Optima boat battery.

My question is this: as the battery loses power with each night, will the treatment pressure (strength of blowing air) decline slowly or will the converter/S9 suddenly stop when it no longer has the minimum power?

There should be little or no effect from the declining voltage of the battery as long as its above about 11.6 volts, which is about 20-30% capacity. You should avoid taking it below 50% if you want a long life. I've never taking my batteries low enough on the CPAP to notice any affect. Some equipment is designed to shut down at 11 or 11.5 volts, and generally works fine until that point.

Hopefully your Optima is a BlueTop or YellowTop, which are deep cycle. I happen to have a pair or Optima Redtop batteries which are starting batteries, not suitable for running a CPAP.

Ok, thank you!