CPAP on battery power issues?

[Vivian L]

We never travel with the humidifiers on the CPAP's but I can see I'm going to need to re-think the system. I know that in the one park I can re-charge the power pak in the office but it takes a full day if drawn down too far, so I should really have two of them, one for each machine.
I think I would need 2 x 100 watt panels to go solar. I'll have to check and see what we've got for our deep cycle marine battery and what it's producing. thanks. I'll keep looking at this.
v

[Timber Wolf]

Vivian, I think you are on the right track, your little power pack is just too small for long term use with two machines. I will say that my very informal tests on my machine show a lot less draw than I imagined from the name plate rating. If I were you I would investigate upgrading my camper battery to a nice real deep cycle group 27 or 31 and a folding 100W panel system. Keep your power pack as a nice backup against poor sun or other issue.

[Vivian L]

Thanks Tim. We always have the power pak charged because we live out in the country and hydro in the winter can go out on us pretty regular. We use it for a lamp, the wood stove too cook and heat but we just wait it out for the CPAP's. It is usually back on within 24 hours.
I am thinking upgrade the camper batter and go from there.
Vivian

[Timber Wolf]

Bad weather was my main thrust in seeing about running my CPAP off a battery. Down here it is bad storms knocking out power usually at night when they can be understandably slow to get it back up. The only thing I know first hand is my 120V CPAP will run two nights easily off the old (old) battery out of my tractor on a small invertor. Which is the old battery out of my pickup. No telling what a real, new, deep cycle battery would do. If I ever blow this CPAP up the next one will be 12V.

[Vivian L]

My next one may be a 12v anyway.
Thanks
v
I'll let you know how I do if I ever get out there and get at it.
Gardens to put to bed right now.
Vivian

[Steve Outlaw]

All the CPAP machines I've seen are 12VDC. Yes, they have the ubiquitous "black box" that plugs into the wall, but it puts out 12VDC. Buy or make a 12 volt cord that can run your machines directly from the 12 volts in your trailer. This will eliminate the overhead of running an inverter.

[Vivian L]

One of our machines has the "black box" but mine does not. Just an ordinary chord with a two prong plug that goes directly into the wall, so I suspect it is not a 12vdc machine.

[beemerphile1]

When we got the wife's CPAP we had a choice between Resmed brand and Respironics brand.

The Resmed is 24v and requires a $70 converter to operate on 12v.

The Respironics is 12v and uses a simple $30 cord.

We got the Respironics and in the process educated the sales person at the medical supply. They couldn't understand why the voltage was an issue and had never been asked before.

[Timber Wolf]

Originally Posted by beemerphile1

The Resmed is 24v and requires a $70 converter to operate on 12v. The Respironics is 12v and uses a simple $30 cord.

That is very interesting as my (older) CPAP is a Resmed 120V but the newer version of this same model is supposedly 12V. I would rather have a 120V machine than something strange like 24V. At least a 120V machine could run off a simple and readily available inverter.

[fusedlight]

Resmed is indeed 24V...I had an email correspondence with the manufacturer. Thank you very much Australia (where the beast is made). Sometime this winter I'll pick up the ResMed 12V->24V gizmo.

[Timber Wolf]

Here is a link to the new version of my model Resmed CPAP: ResMed - S8 Escapeâ„¢ It states "12V or 24V DC input—broad application", whatever that means.

[fusedlight]

I've got an S9... no 12V. Sigh.

[Roger C H]

I used a CPAP for a few years, even running an extension cord into the tent when camping.
I dieted, lost 20 pounds, and haven't needed the CPAP since.
YMMV

[Vtec]

Originally Posted by fusedlight

I've got an S9... no 12V. Sigh.

I have same machine and have been using this dc cord for at least 2 years.

CPAP.com - DC Converter 24V 90W For S9 Machines

[Timber Wolf]

Originally Posted by Roger C H

I dieted, lost 20 pounds, and haven't needed the CPAP since.YMMV

Yeah, well there is that I suppose.<_< I think this thread contains some valuable information particularly about the 24V or 12V issue. If one knows their preferences going in they can ask questions about what device is being spec'd for them and try for a 12V machine if available. I do think that before I spent $85 on a 12V to 24V inverter I would just run it on a $30 12V to 120V Inverter. This is the one Resmed recommended to me: http://www.amazon.com/Tripp-Lite-PV1...+lite+inverter. That way I would have an inverter I could use for other stuff too. This is a small, efficiently sized (no fan) inverter and the CPAP does not seem to draw much juice anyway.

[Vtec]

I tried an inverter first before I got the 12v-24v cord and it killed the battery pretty quick, in a few hours. They use up a lot of battery converting DC to AC.

On a good group 27 battery the cord gets me through at least 3 nights or so. I can go for a weekend not worrying if the battery will die. And if I shut off the water heater on the cpap, much longer.

[Timber Wolf]

Originally Posted by Vtec

I tried an inverter first before I got the 12v-24v cord and it killed the battery pretty quick, in a few hours. They use up a lot of battery converting DC to AC.

On a good group 27 battery the cord gets me through at least 3 nights or so. I can go for a weekend not worrying if the battery will die. And if I shut off the water heater on the cpap, much longer.

The heated humidifier must be the issue. I quit using my humidifier long ago and never tried it that way on the inverter. I guess living in a high relative humidity environment has some benefit.

[Vtec]

Originally Posted by Timber Wolf

The heated humidifier must be the issue. I quit using my humidifier long ago and never tried it that way on the inverter. I guess living in a high relative humidity environment has some benefit.

Well, good luck with the inverter, let us know how it works out. For me all it did was kill the battery even with the water heater turned off. Spending the bucks on the cord was a far cheaper route as I got nearly 3 years and counting out of it. The battery packs they sell for them are in the hundreds and I am just using my boat batteries. If I am in the camper, I am not in the boat.

[Timber Wolf]

Originally Posted by Vtec

Well, good luck with the inverter, let us know how it works out.

It works fine and I was not speculating but "telling you what I know". I would NOT post recommending something I did not know for a fact worked (without a disclaimer). As I stated, this IS the inverter that Resmed recommended (for my machine, an S8). I have used it, it works fine and no undue battery draw was noted. In fact it drew much, much less than the math (machine amps) would indicate. Your mileage obviously varies.

Here is a link to an interesting Resmed document on the topic that lists several machine models: http://www.resmed.com/br/assets/docu...de_glo_eng.pdf

[Vtec]

Timber, glad it worked for you. I read the same pamphlet, got a modified wave inverter as recommended and used up my battery too fast. Your inverter could very well be much more efficient than mine was. As stated from page 9 of the Resmed link you posted:

Why use a converter?
• The converter is more efficient than an inverter.
• The converter provides electrical protection to the flow generator in the event that the adapter
leads are connected incorrectly to the battery.
• The converter provides regulation of the battery voltage: a fully charged battery has a terminal
voltage of 13.5 volts and will reduce as the battery is discharged.
• The converter will shutdown automatically when the voltage drops below 10.5 volts for a 12 volt
battery, or 21 volts for a 24 volt battery. This will protect the battery from damage due to being
allowed to fully discharge.
• The converter provides electrical isolation to the flow generator.

I am always at non-electrical sites so find the cord was the way to go. Would have saved the cost of the inverter I no longer have a use for.