Need help running from battery

[KyFishrman]

I've been on a PR Series 60 System One BIPAP for 18 months or so. In late June I'm going on a two-week camping trip on which I'll need to go maybe 3-4 nights at a time running from battery power. After considerable research, I bought two 35AH AGM batteries, the proper DC cable for my machine, and a "smart" charger suitable for the sealed batteries. If I don't use the hot-plate humidifier, I think I can get 3-4 nights from each battery ... maybe.

The two 12V batteries just arrived today and were 95% charged or better.I topped one off for a few hours as I got my connections sorted out. I hooked to one of the batteries, then plugged into my BIPAP and it does nothing. I did my troubleshooting due diligence and am stumped. The AC-to-DC transformer that I normally use for power tests 12.7 volts at the plug going into the machine. My battery system shows 13.1 volts at its plug, a variance that shouldn't be a problem. Nonetheless, when connected to the battery, I get nothing. One clue may be that the male cigarette lighter plug in the circuit has a red LED that should be lighting, but it isn't. Still, when I put a voltmeter on the plug, it's showing 13.1 volts, even though that LED isn't lit.

Next step was to carry the rig out to my car. I plugged the cig lighter plug into the car socket, the LED lit up and the BIPAP started just fine. I didn't test what voltage the car battery was putting out. Came back inside, ran a full set of continuity, polarity and voltage tests again and I'm stumped. If I have suitable voltage from the battery, polarity is correct, and I'm using the right power cable, why won't my machine run off the battery?

Any troubleshooting suggestions will be much appreciated. I leave in about two weeks and I'd like to test this battery setup here at home for several nights before I hit the road. Thanks!

[CapnLoki]

I've been on a PR Series 60 System One BIPAP for 18 months or so. In late June I'm going on a two-week camping trip on which I'll need to go maybe 3-4 nights at a time running from battery power. After considerable research, I bought two 35AH AGM batteries, the proper DC cable for my machine, and a "smart" charger suitable for the sealed batteries. If I don't use the hot-plate humidifier, I think I can get 3-4 nights from each battery ... maybe.

The two 12V batteries just arrived today and were 95% charged or better.I topped one off for a few hours as I got my connections sorted out. I hooked to one of the batteries, then plugged into my BIPAP and it does nothing. I did my troubleshooting due diligence and am stumped. The AC-to-DC transformer that I normally use for power tests 12.7 volts at the plug going into the machine. My battery system shows 13.1 volts at its plug, a variance that shouldn't be a problem. Nonetheless, when connected to the battery, I get nothing. One clue may be that the male cigarette lighter plug in the circuit has a red LED that should be lighting, but it isn't. Still, when I put a voltmeter on the plug, it's showing 13.1 volts, even though that LED isn't lit.

Next step was to carry the rig out to my car. I plugged the cig lighter plug into the car socket, the LED lit up and the BIPAP started just fine. I didn't test what voltage the car battery was putting out. Came back inside, ran a full set of continuity, polarity and voltage tests again and I'm stumped. If I have suitable voltage from the battery, polarity is correct, and I'm using the right power cable, why won't my machine run off the battery?

Any troubleshooting suggestions will be much appreciated. I leave in about two weeks and I'd like to test this battery setup here at home for several nights before I hit the road. Thanks!

Sorry to hear about your problem. I'm sure it can be sorted out out since there is essentially no difference between the AGM batteries and the car battery. First, a few curiosity questions: what actually are the batteries and how do you know they are 95% charged? And what is your "smart charger"? And what type of wiring harness are you using?

Since the pump runs when plugged into the car (was the car running?) it seems like that side is functioning properly. (If it didn't run I would suspect the fuse hidden in the tip of the power cord.)

So this leaves a few possibilities: the battery wasn't really charged enough to supply the 3-5 amps needed to start the pump. (BTW, when you say the bipap did "nothing" do you mean the control panel didn't come on, or that the pump wouldn't start running?) Its real hard to tell if an AGM is truly charged and functioning well unless you can put it on a load and measure the voltage drop. If you have some other load to use - ideally something that take 50 watts or more - you can use this for "load testing." This brings up a point about voltage testing - it can be real deceptive because it only needs a tiny current to measure voltage. A bad contact (corroded, cold solder, broken wire, etc) can easily test at the proper voltage and then cause a voltage drop when you try to pass serious current. Also, its quite easy to misread polarity with some testers, and most resistive loads such as a simple light bulb will work with reverse polarity. Also, measuring a battery by no-load voltage can be totally misleading. For instance, the 13.1V you measured doesn't mean its fully charged, it means it was recently on a charger and still has the "surface charge" that will dissipate quickly when a load is applied.

The red light not coming on is a red light for me (sorry). It points to faulty wiring somewhere. I'd suspect a hidden fuse but you say it reads 12V so that's unlikely. But still, assuming the batteries and the pump are good, its got to be somewhere in the wiring.

So if none of this leads to a solution you can try hooking your harness to a difference battery, such as a car battery. And you can take the AGMs to a proper "load tester" (any traditional garage would have one). And remember the basic rules of troubleshooting: when all the parts seem to work but the whole fails, its one of your basic assumptions that was faulty, And whatever the solution turns out to be, it will be embarrassing.

[KyFishrman]

Thanks, CapnLoki, that's exactly the kind of help I was seeking. You are correct that I concluded my new AGM batteries are charged based on the 13.1 volts, not based on a true load test, so that's definitely a possibility. Also, I had to custom build one piece of wiring; it has a 12V cig socket on one end and one of those can't-do-it-wrong 12V offset connectors on the other end. Building that piece was necessary in order to get a 12V socket that would attach to the AGMs. When I tested on my car, I didn't need that homemade cable in the circuit, so I didn't use it. I now need to go out and test on the car with that piece added into the circuit.

Again, thanks for helping me narrow down the troubleshooting. When I uncover the problem, I'll post it here.

[amenite]

... Also, I had to custom build one piece of wiring; it has a 12V cig socket on one end and one of those can't-do-it-wrong 12V offset connectors on the other end. Building that piece was necessary in order to get a 12V socket that would attach to the AGMs. ...

When I bought the 12V kit for my DS560 it came with the fused cigarette lighter socket with alligator clips (don't forget to bring some spare fuses). I have other similar sockets but this one was part of the 60 series kit I purchased:

https://www.cpap.com/productpage/respir ... cable.html

[KyFishrman]

Sorry to hear about your problem. I'm sure it can be sorted out out since there is essentially no difference between the AGM batteries and the car battery. First, a few curiosity questions: what actually are the batteries and how do you know they are 95% charged? And what is your "smart charger"? And what type of wiring harness are you using?

The red light not coming on is a red light for me (sorry). It points to faulty wiring somewhere. I'd suspect a hidden fuse but you say it reads 12V so that's unlikely. But still, assuming the batteries and the pump are good, its got to be somewhere in the wiring.

So if none of this leads to a solution you can try hooking your harness to a difference battery, such as a car battery. And you can take the AGMs to a proper "load tester" (any traditional garage would have one). And remember the basic rules of troubleshooting: when all the parts seem to work but the whole fails, its one of your basic assumptions that was faulty, And whatever the solution turns out to be, it will be embarrassing.

Well, I took a few more steps today, but no "Aha!" moment, I'm afraid.

To answer some of your questions, Capn, the batteries I bought are UB12350's https://www.amazon.com/gp/product/B007Q ... UTF8&psc=1. The charger is a 5AH Deltran Battery Tender https://www.amazon.com/gp/product/B002D ... UTF8&psc=1.

I took both batteries to AutoZone today and they tested 100%. I also took the cable I had to build and tested it by hooking to one of the batteries and then plugging in a 12V tire inflator. Ran just fine. I'm beginning to think the BIPAP is "looking" for something -- a particular amperage, particular voltage, whatever -- that it's just not sensing with this battery hookup and for that reason it's not switching on at all.

[Gasper62]

Use some jumpers to see if your batteries will light up (brightly) an automotive headlight bulb or an old school sealed beam . If they do, it's gotta be your made-up harness. Continuity testers and jumper wires w/alligator clips are very handy for this type of troubleshooting. I bought this rig from Amazon to run off a marine/deep cycle battery during outages, it works like a charm along with the adapter cable for PR machines that I got from our host's site. Good luck. ~~ http://smile.amazon.com/BESTEK-Battery- ... ge_o07_s01

[Gasper62]

Wow ! I just saw that the harness that I paid $9.99 for..... is now $60.00 more ! WTF ? Anyway, there are many others around and available at a reasonable cost.

[Gryphon]

I set my system up with a 110 AH deep cycle marine battery and a few of these.

https://www.batteriesplus.com/productde ... 081=0069=6

https://www.batteriesplus.com/productde ... 081=0069=8

Everything already wired with fuses so it takes all the guess work out - you may need to rig something though if your using the smaller batteries.


viewtopic/t112101/viewtopic.php?f=1&t=1 ... 5#p1072455

This was the post were I broke down my whole set up and more or less how I built it. If weight isn't a big issue I'd go with a wonking big battery can always get a little dolly cart to roll it around in.

I'll say again the links aren't a recommendation / I didn't buy my stuff from them just use it as cost and visual example. Prices are about the same location to location.

Hope this helps.

[KyFishrman]

Problem solved! Finally I put my ego aside and asked, "OK, so what components here are not 'factory' or which did you modify in some way?" The obvious answer was that there was one cable I had to build because I needed round battery connectors on one end and a female cig socket on the other. I was 100% sure I had tested things and got the polarity right, but ... I wasn't 110% sure. I disassembled that one cable, switched the polarity, and BINGO!

Thanks for reminding me that even when you're 100% sure of something, there's still room for a mistake.

[KyFishrman]

Use some jumpers to see if your batteries will light up (brightly) an automotive headlight bulb or an old school sealed beam . If they do, it's gotta be your made-up harness. Continuity testers and jumper wires w/alligator clips are very handy for this type of troubleshooting.


BINGO! It was the made-up harness. I don't see how, but i got the polarity wrong. Fixed that and all was right. Thanks!

[palerider]

Use some jumpers to see if your batteries will light up (brightly) an automotive headlight bulb or an old school sealed beam . If they do, it's gotta be your made-up harness. Continuity testers and jumper wires w/alligator clips are very handy for this type of troubleshooting.

BINGO! It was the made-up harness. I don't see how, but i got the polarity wrong. Fixed that and all was right. Thanks!

I'd had the thought that it might be that, but then kinda went "nah" mentally... I'll try and keep it filed away in my head in case someone else comes up with the same problem.

glad that you got yours figured out

[CapnLoki]

Problem solved! Finally I put my ego aside and asked, "OK, so what components here are not 'factory' or which did you modify in some way?" The obvious answer was that there was one cable I had to build because I needed round battery connectors on one end and a female cig socket on the other. I was 100% sure I had tested things and got the polarity right, but ... I wasn't 110% sure. I disassembled that one cable, switched the polarity, and BINGO!

Thanks for reminding me that even when you're 100% sure of something, there's still room for a mistake.

Glad to be of service!

Sent from my SM-T350 using Tapatalk

[CapnLoki]

Use some jumpers to see if your batteries will light up (brightly) an automotive headlight bulb or an old school sealed beam . If they do, it's gotta be your made-up harness. Continuity testers and jumper wires w/alligator clips are very handy for this type of troubleshooting.


BINGO! It was the made-up harness. I don't see how, but i got the polarity wrong. Fixed that and all was right. Thanks!

I wasn't sure why you wanted to make up that cable. The BatteryTender charger should come with ring terminals to a plug that connects to a $10 socket. Doing this as a two part cable allows you to add a 5 to 1 to splitter that allows the charger plus the cpap (plus a few other gadgets) to be connected at the same time. You can run this as a UPS system.

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[Gasper62]

Aren't the ring terminals gonna' be a pain in the rump whenever you need to change to the other battery ? (unless you wired the batteries together in parallel)

[CapnLoki]

Aren't the ring terminals gonna' be a pain in the rump whenever you need to change to the other battery ? (unless you wired the batteries together in parallel)

If each battery has the ring to connector cable then the switch only takes a second. You just have to resist the evil temptation to connect the batteries together. (Actually the cables from BT have a fuse built in.)

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