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Resmed S9 optimal battery runtime configuration questions
#1
Resmed S9 optimal battery runtime configuration questions
I have a Resmed S9 and the 90 watt 12-24 volt DC power supply. I understand that there is rarely a 1:1 trade off, thus my questions.  My questions are in 2 parts. Ultimately, I'm looking at the most effective configuration.
Part 1 - If I use two 12 volt batteries of the same size which would be the most advantageous wiring method, in series. in parallel, or no difference?

Part 2 - What would be a better configuration; two 12 volt "X" amp hour batteries wired in series to produce 24 volts, or one 12 volt at double (X*2) the amp hour ranting of the 2 smaller ones.
Crimson Nape
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#2
RE: Resmed S9 optimal battery runtime configuration questions
Ifvi am getting you question right. I know for instance when we have a 24 volt scissor lift we get longer battery life using 4 -6 volt deepcycle batteries wired in series for24 volts. I think the same applies to your question.
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#3
RE: Resmed S9 optimal battery runtime configuration questions
Thanks!  I think srlevine1 answered my question in another thread (Referenced Thread).  There is some energy loss whenever you change it.  I'll experience less loss if I input 24V into the power supply as opposed to inputting 12V and letting it convert it to 24V.
Crimson Nape
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___________________________________
Useful Links -or- When All Else Fails:
The Guide to Understanding OSCAR
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Apnea Helpful Tips

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#4
RE: Resmed S9 optimal battery runtime configuration questions
There is not enough energy loss with ResMed's 12-24 V DC converter to worry about. I had a friend once that referred to a syndrome called PII (Preoccupation with Inconsequential Increments). I think this falls under that category.

If ResMed was not of a mind to force their customers into buying their converter to make the unit run, I would say sure, go with 24 V direct. But since you can't go 24 direct, then just use 12 and don't worry about it. Without heated humogrification, the S-9 on the converter is really energy efficient anyway. I can safely get 8 nights out of a 35 AH battery on it.

OMMOHY
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#5
RE: Resmed S9 optimal battery runtime configuration questions
A big Thank You for that information.  I didn't know what the conversion loss would be.

Red
Crimson Nape
Apnea Board Moderator
www.ApneaBoard.com
___________________________________
Useful Links -or- When All Else Fails:
The Guide to Understanding OSCAR
OSCAR Chart Organization
Attaching Images and Files on Apnea Board
Apnea Helpful Tips

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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