running a legacy bipap off DC batteries...

coconut · Post by **coconut** » Tue Jun 03, 2008 2:24 pm

Hi, I just bought a legacy bipap machine (new), not one of the little M-series.

I see it is 24-volt and not 12-volt like my older remstar auto cpap which is built on the same frame. If I had checked the specs closely I'd have seen that.

Anyhow, I like the idea of being able to do battery backup, and have the adapter for my old 12v system. However, I see that the adapter for this one is $165 and contains a transformer to bump 12v up to 24v. It also has a proprietary plug to thwart tinkering (one presumes).

In my situation, though, I'm not looking to sleep in a truck, I'm looking at a home backup battery system for grid failures - and I already own it. It consists of two 12v deep-cycle batteries wired in parallel to make one larger 12v battery. Batteries last longer if you don't discharge them as deeply, plus having more power means being able to deal with a longer grid failure, such as after a tropical storm here in Hawaii.

It sure seems as though it'd be more elegant, and simple, to just take a minute and re-wire my two batteries in series to have a direct 24v power source. This would presumably obviate the need for an inefficient and pricey transformer. So, aside from not having the proprietary plug, and cautions about not messing with things, is there some specific reason not to directly power it with 24v?

I won't be trying this anytime soon, just asking to see what you folks say.

thanks.

Dme Daddy · Post by **Dme Daddy** » Tue Jun 03, 2008 2:38 pm

There has never been a 24 volt Respironics Bipap made. They are all 12 volts. Really.

coconut · Post by **coconut** » Tue Jun 03, 2008 4:43 pm

Actually, no. I'm sitting right here looking at one and I guarantee you it's 24 volts.

See specs: https://www.cpap.com/cpap-machine/bipap ... iflex.html

From which I paste:

AC Voltage Source 100 to 240 V, 50/60 Hz
DC Voltage Source 24V (when operated with the external DC power adapter accessory)

FYI, it comes with an EXTERNAL power supply which feeds it 26v through a weird little plug. There's no 12v going into this baby, nohow.

So, back to my original question. Thanks.

Bearded_One · Post by **Bearded_One** » Tue Jun 03, 2008 4:53 pm

Other than the weird connector issue, there is no reas0on you couldn't power it from a 24 volt battery string. You will also have to use a 24 volt charger.

24 volts is a common voltage in several applications, and is used in some telephone applications.

coconut · Post by **coconut** » Tue Jun 03, 2008 6:01 pm

Other than the weird connector issue, there is no reas0on you couldn't power it from a 24 volt battery string. You will also have to use a 24 volt charger.

That's my thinking. Any suggestions anyone for where to get the weird plug? Probably not...

RE charging, I figure to just use the 12v charger I use to keep a float charge on them in parallel, and then if needed I rewire the batteries to series and presto - 24v.

dj

Snoredog · Post by **Snoredog** » Wed Jun 04, 2008 12:09 pm

[quote="Dme Daddy"]There has never been a 24 volt Respironics Bipap made. They are all 12 volts. Really.

coconut · Post by **coconut** » Wed Jun 04, 2008 12:29 pm

Snoredog - you seem to be well informed on all this stuff. Do you have any idea what the name of the weird 24v plug is, that is the type, so I could make my own 24v power supply out of 2 batteries? It's an odd one, and I have no idea where to look for the information. Figured I'd ask in case you know, or there might be some obscure spec sheet somewhere which would say.

I could always take the power supply to radio shack, but it's looks a bit too obscure for them.

I wish I had read the fine print and realize that these tanks were 24v, I'd probably have just gotten the M series. Oh well, I'll work around it.

best

ColinP · Post by **ColinP** » Wed Jun 04, 2008 3:18 pm

It might be worth posting a pic of the plug, someone may then recognise it and be able to give it a name, which would make finding it much easier.

The other way to get 24V easily is to get hold of a truck battery, they're usually 24V.

Colin

coconut · Post by **coconut** » Wed Jun 04, 2008 4:30 pm

is there a way to upload pix to this website, or would I have to host it elsewhere and use html?

ColinP · Post by **ColinP** » Thu Jun 05, 2008 12:11 am

coconut wrote:is there a way to upload pix to this website

No

coconut wrote:or would I have to host it elsewhere and use html?

Yes

Goofproof · Post by **Goofproof** » Thu Jun 05, 2008 11:24 am

ColinP wrote:It might be worth posting a pic of the plug, someone may then recognise it and be able to give it a name, which would make finding it much easier.

The other way to get 24V easily is to get hold of a truck battery, they're usually 24V.

Colin

Most truck systems use two 12 volt batteries in series to make a 24 volt system.

6PtStar · Post by **6PtStar** » Thu Jun 05, 2008 12:40 pm

If you want to PM me, I will give you my e-mail address and you can send it to me. I will be glad to post it to my Photobucket account and put it on the thread.

Jerry

ColinP · Post by **ColinP** » Thu Jun 05, 2008 1:27 pm

Goofproof wrote:
ColinP wrote:It might be worth posting a pic of the plug, someone may then recognise it and be able to give it a name, which would make finding it much easier.

The other way to get 24V easily is to get hold of a truck battery, they're usually 24V.

Colin
Most truck systems use two 12 volt batteries in series to make a 24 volt system.

I never knew that. Last time I was was up close and personal with a truck was in the army in the early 80's, and those had huge big 24V batteries. (Which were usually flat, hence the upclose and personal bit - we had to push start them on cold winter mornings.)

6PtStar · Post by **6PtStar** » Thu Jun 05, 2008 2:39 pm

OK folks this is what the 24 volt plug looks like for coconut needs to run her BiPap Legacy. Any one know of a source for something that looks like this

Jerry

Bearded_One · Post by **Bearded_One** » Thu Jun 05, 2008 3:20 pm

That is the strangest connector I have seen in a while.

cpap.com wants $165 for a 12V > 24V power adapter with that connector.

running a legacy bipap off DC batteries...

running a legacy bipap off DC batteries...

they're all 12 volts?

weird plug & 24v

snoredog - RE odd plug

posting pix

Re: posting pix