My battery backup setup

[sdb7802]

In regards to oscope display.
If I am reading the scope correctly? The sense line resting voltage seems to be almost 13volts.
During power up, your lable of 1.8volts to me looks like 6 volts on the scope. Also it looks like when data is going on it is almost going to ground.

The trace is the only one I kept while working on this about six months ago.

The blue trace is 2 volts per major division. What I labelled as 3 volts is actually 3.3 volts. The horizontal dashed white line is the ground reference for the blue trace. Also, the 1.8 volt pulldown value is probably a little off.

I used the 1.8 volt value to try to illustrate what Dave was describing about the sense line activity.

I'll post some more traces later.

[ve7ltd]

Once the S10/A10 unit has booted with the sense line connected, I believe you can disconnect the sense line and it continues to work. So I can confirm 100% that the unit will not run on anything under about 20-22V. This is consistent with all the findings I have seen. The sense line is only used by the machine on initial boot, then it starts to send some sort of data. So even if I ground or disconnect the sense pin, as long as the machine is booted it seems to keep working. So the shutdown has nothing to do with the voltage on the sense pin AFTER boot.

Martha, Perchas is mentioning that I am the creator of the IRLP system which he has used to communicate around the world. Small world.

On another note - i fell asleep without my machine last night, and today i feel like crap.... I can't seem to function at work. Maybe I'll go home and have a CPAP-nap and recharge.

Dave

[Marthajoy7]

Wow; I am impressed. I used to do more with electronics but with my health and memory loss, I have a hard time just trying to care for myself. Tremors on both arms and legs makes soldering a challenge. So if I can find premade modules, that is so much easier for me these days. I remember back as a kid, using ww2 govt surplus eqp converted to amateur radio. Had a neighbor ham operator whom gave me my first test.

I really hope you take care of yourself. Get some quality sleep as soon as you can. I am retired/disabled so I sleep anytime I feel the need.

Really interested in idea that the pin can disconnect after operation is started.
maybe a momentary switch on startup. Turn off auto-sense to make sure unit does not shut down from mask leakage. Or maybe something more elaborate. Sense line on 24v line. If current is not flowing pin is connected, when current flows, pin connection is open. anyway just ideas. Just wondering if change in data voltage levels affects data being recorded on sd card.

[ve7ltd]

There is no need to disconnect the sense line - I was just saying that it would not cause the machine to shut down from a low voltage on the sense pin. I will get my setup out of my trailer this weekend (stored at another location), and take some pictures and play around a bit more.

When I found the 47k value, I had just received the DC-DC converter unit in the mail, and I had 2 hours to make a working setup before I sent on a 10 day camping trip. I have a 1500 true sine wave inverter, but it sucks a lot of extra power, so I wanted to make this solution work.

I need to clean up the cabling a bit. I may also just make a spare and build a battery backed up DC floating backup and take lots of pictures. That way others can build the same thing and hopefully have the same success as I have.

I made a post in the UPS backup thread earlier today where I outlined my ultimate bedside setup using an AGM 12V battery, 12-24 DC-DC converter unit, 47k ohm sense pin cable, and a smart charger to make a 2-3 day on backup system that required no intervention if the power cut off or turned back on.

This is the DC-DC unit I bought: [link removed]

Dave

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[Sleepster]

I will keep using my PR System 1s that don't need no stinkin' third line! Just a plain battery that I know how to run.

Me, too. It's my back up machine for use during extended outages. If we ever have one. Oops! I just tempted fate!

[Marthajoy7]

That is fine, but I need a Bipap. Insurance is renting me an AirCurve 10, and they do not care what happens to me if power goes out! But I do.

[Sleeprider]

MJ, the PRS1 60 Series BiPAP Auto would give the same therapy at 12 watts. You might be able to find one at a pretty low cost. I have one.

[Marthajoy7]

I have parts on the way to be able to power Resmed AirCurve 10 Vpap from strictly battery power. No inverter needed. Told I will probably draw 8-10 watts/hr id humidity and heated tubing is not used. Most my batteries are 24ah to 40ah in size. 2 - 40ah batteries in series has almost 200 watts of power. That would equate to about 20 hrs of operation per battery charge. I have a number of 24v chargers from my mobility devices. I could even run setup as a UPS. Charger to batteries to device, if power goes out, batteries supply power, if AC comes back on, charger auto recharges batteries. Not as expensive as paying over $700 for a refurbished backup machine.
We just needed to figure out what it was that Resmed did to make is so they thought, only they could provide power for the machines.
I am considering using 47k ohm resistor to center pin only on power-up. That would cut down battery drain slightly and not mess with data stream voltage levels. Which may be why Resmed is using 3.3v converters.
I will get there, and much thanks to these wonderful engineers helping us.

[Marthajoy7]

Wow, I really messed up on my est. power. 24 x 40 is about 960 not 200w
So at 10 watts/hr that would be 96 hours.
But I want to power 2 machines off one set so probably around 48 hours for 2 machines.
Parts starting to come in now, So over the next week or so

[Perchas]

This is the DC-DC unit I bought: [link removed]

Dave

Is this ?, search on eBay "DC Converter 240W DC 12V to 24V 10A" barato, barato $ 28,00.