Devilbiss Intellipap Auto -- fits into a nice sized bag; good quality machine; not too expensive

Very interesting. Is this the product that you're talking about? http://www.amazon.com/Duracell-DPP-600HD-Powerpack-Starter-Emergency/dp/B000TKHMWK/ref=sr_1_1?ie=UTF8&qid=1337801901&sr=8-1 It looks like it has the same basic battery inside of it that I used for my backup -- a sealed, lead-acid AGM b...

Sorry that I don't know exact answers to your questions, but I can give you some general information based on some recent experience camping with my CPAP. 1. I don't know exact figures, but I believe that if you want to get the maximum amount of time out of your battery, get a DC cord and connect th...

Well, I used the back-up battery while camping for two nights this past weekend, and it worked perfectly. When I travel, I use my back-up machine -- a Devilbiss Intellipap Auto, which has a 12-volt DC input. I plugged this directly into the 12-volt "lighter" output from the battery that I built, and...

For the record, you don't need to be "handy" or skilled to build John's design. If you can turn a screwdriver or make a small hole with a drill, then you can build it.

When you see how much more battery power you get for the same $, you will want to build one rather than buy.

Check out posts by a member named JohnBFisher. He's like the battery guru around here.

I just built one using his design, and it was easy. The parts mostly come from a site called http://www.atbatt.com. They are a very good vendor.

Good luck!

Well, I finally received all of the parts from At Batt, and I put them together last night. It didn't take much time at all, and the only real challenge was drilling the holes in the right size for the outlet on the battery box. The whole thing took less than an hour. I was going to post photos of t...

Aha, yes! Good to know. See, I just bought all of the oarts you recommended without really understanding what each one is, but I see now. Anyway, I will post photos as the pieces come in, anf thanks again for the help.

You got to love Devilbiss for using a standard AC connector rather than some proprietary design. Have a great cruise!

John I will do it. Going camping in a few weeks with my son, so it will be pretty soon. One more question for you too, if it's ok. In your earlier post you mentioned that it would be good to add a fuse and a master on/off switch. Can you give me the components that I would need to buy to add this to...

Well, I appreciate all of the good information here, especially the design supplied by John, and I'm excited to get this project started. It's been bothering me quite a bit since I started CPAP that I would be in big trouble if the power ever went out, but it hadn't actually happened until last week...

Well, I appreciate all of the good information and advice. Like I said, without,this site, I would probably just buy one of those Goal Zero batteries and just learn to live with it. I think the setup recommended by John is going to work much, much better. One last question for you -- how do you know...

Since my battery is strictly to use for when the power goes out and one or two nights per year while camping, I'm planning to use it without the humidifer. That's why I picked a 35 Ah battery, and I specifically chose one to fit in a U1 size box, which I thought would be more compact and convenient....

John I am following your design exactly. It's the reason I thought to try this.

I decided to go with a U1 size because I didnt want it to be too big to carry. I just hope that 35 Ah is enough.

To the guest - the shipping was free, and I looked for a local store, but there are none in this area.

Had my worst night ever last night, when the power went out suddenly, and I started to think that I was going to have to sleep in the car just to have power for my CPAP. I looked at some of the ready-made backup batteries on the market, but either they have gotten bad reviews or they cost more than ...