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feeling_better wrote:Almost nobody designs with the requirements of a current limited supply.

Current limiting is actually quite common. In general, the power supply usually operates at constant voltage, but may be designed to limit current as well. This is mainly for safety, but sometimes, some other components need a "soft start." If the power supply is designed as part of the overall machine rather than as a general purpose DC supply. It's also getting more common for there to be more communication between the "power supply" and the rest of the machine for things such as "voltage good, go to standby mode, more/less voltage, power for humidifier available, etc."

I suspect in this case, it's only "humidifier/heated hose power available" and "make you buy the name brand power adapter" signals.

I don't have one of these to look at, so it is hard to be of any real help. But, you say there is about 3v on this 3rd line and 24v between the 2 main lines. So I am imagining a triangular plug with 3 prongs. When you measured the voltage (dc), were you referencing a ground point, like maybe a chassis ground or earth ground point? And if so, lets call the prongs A, B, and C. From earth ground to point A you had 24v, and from earth to point B you had 0v, and from earth to point C you had 3v. This is how I am imagining what you have explained-is this right?

So, assuming this is correct, I would also assume that the 3v is for the digital circuit board controls since they will run at a range of voltages around 5vdc. I would also assume that the engineers would make things fail-safe in the event of a power supply failure. So, I would open (disconnect somehow) point C and see if the unit even turns on. If the above is true I would think that nothing would happen. And if this is the case you could just get a voltage regulator from Radio Shack and still take care of that line (or you could probably fashion up a few 9v batteries with a voltage regulator for this. I've seen some made in an empty Sucret Lozenges tin with 2 9v batteries. This is not exactly like that, but you'll get the idea: https://www.youtube.com/watch?v=rFmVfJC9scA

From there, you just have to come up with the 24v. This will probably be the tougher part. Sorry I can't be of more help, good luck!

feeling_better wrote:GUESS / SPECULATION: For the s9 power supply brick, the third pin may not be a signal but a second voltage for power. That is, the power supply provides 24V and 3.4V, the latter most likely is used for running the processor and all the logic; the former for the air pump. At this point it is a pure guess on my part. Any electronics members here have any comments or other speculations?

I would like to see someone figure this out so they can stop getting robbed. I googled 3 pin din (or mini-din) and got plenty of hits. Mouser has Mouser Part #: 161-2603 see if that looks close? Other places had some for $.50.

I bought a Prius, because I'd rather give money to the Japanese (our friends) than Big Oil

You're my heroine, chunkyfrog!!!

I found this thread searching for battery backup options. Rather than starting a new topic I thought I would bump this one. Having struggled with this issue for camping and or power failure for my S9 Elite I bought an inverter type generator. So testing my S9 Elite, H5i, climate line hose at max temp setting with a pressure of 11 plugged in to 120vac it draws a max of .6 amp or 72 watts. This drops off to .5 amp 60 watts and .4 amp 48 watts. Cycled up and down as I tested it while wearing mask. Anyway the generator worked great, however it makes a little noise all night long, about 55dB. A battery would be 0 dB. I'm to understand that I need 24vdc to run this unit. Two 12 volt Optima yellow tops in series are on my mind. But I still need to figure out how or what connection to the S9 is needed. I'm sure I can get there??? Anyone know of anything thats plug and play? Or do I need to figure out this third connection of a lesser voltage?

Journeyman wrote:I'm to understand that I need 24vdc to run this unit. Two 12 volt Optima yellow tops in series are on my mind. But I still need to figure out how or what connection to the S9 is needed. I'm sure I can get there??? Anyone know of anything thats plug and play? Or do I need to figure out this third connection of a lesser voltage?

This has been discussed quite a bit in the past. I don't believe anyone has deciphered the function of the third wire. The drive to do so somewhat fizzled out after Resmed came out with their 12 volt power brick. As for myself, since I already had a 12 to 120 volt converter I opted to just buy a decent deep cycle battery. This past summer I bought a second one. Between the two I made it through 4 nights with power to spare using the humidifier. The biggest problem I've encountered with the deep cycle battery is their recharge rate is lower than a car battery. Last year I used the first of the two batteries and recharged it each day from my pickup. Even with all the charge current going to the deep cycle with a charging time of an hour or more, the battery still dropped down to about 1/3 charge after 4 nights of use.

What would really be nice would be a small, say about 150 to 200 watt, propane powered generator, sound insulated and with a quiet exhaust!

I think the power connector is a custom plug as well, but I could be wrong.

Wow, this took some spare time to investigate, only to guess that the three prong connector could be a proprietary connector that as had been said in the past. Or, I also found that it could be a United Kingdom round 24vdc three pin mini din connector. Some UK standard 24vdc configuration. ??? A company in the UK offers what looks like them at a 1000 each to 10,000 each per order, made in China. I will have to measure pin size and spacing, as well as the electrical output from the 120v AC to 24v DC converter brick. When I get back on my feet I could possibly make a set of them. Also I'm guessing that there are ferrite beads on the cords. Ferrite beads are used to suppress high frequency noise. Possibly eddy currents from your 120 volt lines. They are electric chokes or EMI, "electromagnetic interference" filters. This is medical equipment after all. I'm not sure that you would need this with a battery supply. Not an expert at any of this but learning all the time...

If your using a 12 volt or 24 volt battery just use this https://www.cpap.com/productpage/DC-Con ... hines.html

squid13 wrote:If your using a 12 volt or 24 volt battery just use this https://www.cpap.com/productpage/DC-Con ... hines.html

Yeah, I used that with a 12V battery camping this summer, and it worked just fine with my CPAP. I didn't use the heated climateline and used the humidifier in "passive" mode. Battery worked quite well, and lasted better than I expected.

Here's another useful document:

http://www.resmed.com/us/assets/documen ... lo_eng.pdf

Thanks squid this is just what I have been looking for. Why I never found it before while looking for something like it I'll never know. This looks to be plug and play, as long as I can get the box open. Thanks again for the info.....

Thanks Roger I saved that info as well. Looks like I'm on my way to blissful quiet camping. Thanks again...

hi i saw this while searching for a replacement mini din connector and just wanted to share something. My fathers bipap machine uses the 3 prong as well and the plug came apart so i stripped it back and the smaller of the 3 prongs isn't wired to anything. My guess is its there to prevent you from plugging in one prong and shorting the machine since the jacket is grounded. Hope this helps someone.

I am hoping this isn't too hard to achieve. DC buck/boost modules are easily available on eBay and reasonably efficient. Power requirements (without humidifier) are very low, circa 3W for modest pressures. The 3.3v line (third pin) can also be provided from a separate regulator, and its demands must also be low. I think this would be less than 0.5A. The connector may be available via Digikey or similar but if you buy the RPS 2 cable from Resmed it has it on it. Cut and shut. As I want to do this for motorcycle travel using a 4.7ah bike battery I have purchased the requisite parts and will let you know how I go. Cheers

Kpavey wrote:I am hoping this isn't too hard to achieve. DC buck/boost modules are easily available on eBay and reasonably efficient. Power requirements (without humidifier) are very low, circa 3W for modest pressures. The 3.3v line (third pin) can also be provided from a separate regulator, and its demands must also be low. I think this would be less than 0.5A. The connector may be available via Digikey or similar but if you buy the RPS 2 cable from Resmed it has it on it. Cut and shut. As I want to do this for motorcycle travel using a 4.7ah bike battery I have purchased the requisite parts and will let you know how I go. Cheers

Or you could simply purchase the DC/DC converter from Resmend - $84 - nicely packaged with a warranty and the proper connection. I don't see what you gain by cobbling together a solution, especially given that the specs of the third wire are not well understood. Also, a 4.7 ah battery will be marginal. If you run it down completely every night, it will have a short lifetime. You can get a 7 ah AGM battery, about 3 pounds, for under $20.