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Thanks for clearing that up. I feel like I've been though this discussion before and just forgot. Definitely more complicated than I thought or remember with the Resmed machines. Doable, but not easy. I guess I would look at getting a Phillips Resperonics which allows for a simple 12v hook up.

Rob K wrote: ↑

Sun Jul 15, 2018 10:33 am

Are you set on getting a different machine than what your used to? From what I've read over the years the S9 is one of the best units on the market. The simplest thing would be to run your S9 from two 12v batteries in series to get the needed 24 volts.

The best solution would be to get the new pump (whatever, but staying with ResMed is easy) and use that at home. Keep the old S9 for camping/backup. If the S9 is dying then this would be a time to consider how important it is to move to the most efficient pump.

I never saw the advantage of using two batteries to make a 24 volt pack. There are too many little complications and the only saving is the DC converter. By staying in the 12V world there are a variety of benefits, like running other devices, charging from any source, jump starting, etc. I use a 4 battery bank built of 6volt batteries, but once setup it isn't touched for 6-7 years so it acts like a single battery. It would be a mess if I had to take it apart for charging, etc.

That's some good insight. I was thinking more along the lines of a battery setup dedicated to xpap since that's what I do for long stays. Everyone has different needs though.

If money means less than using a 12 volt XPAP, They do make 24 volt wet batteries. I took one from Chopper in 1966 and tapped it to output 12 volts to run me face shaver under my bunk, it was out of a Huey.

I'm sure the 24 Volt battery option is more costly. I don't like Resmed for many things, proce fixing marketing, 24 volt power so they can sell more high priced add on's.

I use the K.I.S.S. Method for everything, Resmed doesn't come close, they use the $$$$ Method. Jim

That's why I was thinking two 12v batteries would be a better option, less expensive. And like the Cap'n says you would have more options to run other equipment with 12v batteries.

Rob K wrote: ↑

Sun Jul 15, 2018 4:56 pm

That's why I was thinking two 12v batteries would be a better option, less expensive. And like the Cap'n says you would have more options to run other equipment with 12v batteries.

But, they're not. 12>24v boost converters are very efficient > 95%,

yeah, you get half the runtime out of one battery vs two, but also half the weight.

There are some third party resmed compatible boost converters out there now, for less $$

95% efficiency is pretty good and hard to argue with that. I'm glad you guys are on top of this stuff. Always learn a lot.

So bottom line it sounds like the best option for camping with Resmed is to get something like an S9 with the converter and the proper sized 12v deep cycle. I keep think of switching to a Resmed unit for my next machine. Good info for the OP also. The Poweradd must have been what was giving the OP problems.

Thanks for replies, I use inverter chord, and the battery I posted for a camp trip I have to fly to. For car camp trips, I use deep cycle marine battery.

Dive Apnea wrote: ↑

Mon Jul 16, 2018 10:17 am

Thanks for replies, I use inverter chord, and the battery I posted for a camp trip I have to fly to. For car camp trips, I use deep cycle marine battery.

There's a huge difference in an 'inverter' and a 12v dc cord.