My ResMed S8 Autoset portable power solution

[akeegan]

I given this problem way too much thought. I want a portable power solution to my S8 AutoSet II to take on a sailboat. I have a mid-priced jump pack with 12 VDC cigarette output from O'Reilly's auto parts. I decided against a directly wired, fused, properly gauged 12 VDC solution because I don't think the potential benefits outweigh the possible risks to the S8.

Here is a very informative link from ResMed that helped guide me. Note that is dated 2007, so your machine may not be on it. Mine isn't; I will have to extrapolate the data.

http://www.resmed.com/us/documents/batt ... ts-usa.pdf

I always thought you would need a pure sine wave inverter for your CPAP. Per Resmed, you only need a modified sine wave inverter. There is a big price difference between the two. Remember, though, laptops, most electronics, and I believe AC cell phone chargers need pure sine wave.

I will design this based on the article's recommendations using the S8 Autoset Vantage specs. A 150W inverter, either pure or modified sine wave depending on my finances (pure is really the best.) My O'Reilly jump pack. H4i humidifier heater set to off (way too much current draw otherwise.) 10 cm H2O. Power draw of 1.4 A, with a ResMed-computed 50% safety margin. This means if I have an 18 AH battery in my jump pack (haven't taken it apart yet to be sure), it will run my APAP for 12.9 hours (18 AH / 1.4 A = 2.9 H), with a 50% reserve. Plenty for me. Remember, jump packs are either gel cell or AGM design, not deep-cycle. A jump pack expects to be charged as soon as possible for long life. As do car batteries. Don't buy inverters from Walmart, unless it's a Schumacher. Their other brands get rated at junk-bond levels.

I'll be back after I build, test, and record data and performance. One caveat; I have NO idea how this will affect the longevity of my nearly new jump pack.

Al

[GumbyCT]

I decided against a directly wired, fused, properly gauged 12 VDC solution because I don't think the potential benefits outweigh the possible risks to the S8.

What risks to the $8?

I simply reversed the connector for my Respironics and powered up an S8 I have laying around.
viewtopic.php?f=1&t=64943&p=652587&hili ... le#p652587

It was that simple. And you will get many more hours sailing or sleeping. Your call.

[akeegan]

I decided against a directly wired, fused, properly gauged 12 VDC solution because I don't think the potential benefits outweigh the possible risks to the S8.

What risks to the $8?

I simply reversed the connector for my Respironics and powered up an S8 I have laying around.
viewtopic.php?f=1&t=64943&p=652587&hili ... le#p652587

It was that simple. And you will get many more hours sailing or sleeping. Your call.

GumbyCT,

Good link. I've PM'd you.

Al