DC power cord

I use a RemStar Plus cpap system. I wanted to use the cpap on my boat when I sleep overnight. I called my local medical supplier and they stated the DC power cord would run about $80. I told them to keep the cord.

I went to Radio Shack and purchased a heavy duty (5 amp) DC power cord with the cigarette lighter attachment on one end and a plug (with tip being positive) for the other end. I plugged in the unit and it lit up. Did a quick startup and the unit seemed to work.

When camping out on the boat a few nights ago, I plugged in the machine and set up for a good nights rest. A few minutes after running, the machine lite up a couple of times and then stopped. I looked at the display and a code E36 (I believe, I was very tired) was displayed. I disconnected the power cord and reconnected it. The machine ran for a minute and then quit again.

First, I assumed the plug should have a positive tip and negative ring, but, is this correct?

Second, what is the DC voltage range of the cpap?

Third, does anyone have a list of error codes for the RemStar Plus?

I searched the internet and found a note about DC power cords. It stated that certain Respironics cpap machines will not work above 11 cm H20 using the DC source.

So, I adjusted the pressure to 11 cm from the originally setting of 12 cm and the machine seems to work. I don't know if the information is true. Does anyone know about limitations using DC power?

Thanks for all your help.

BarryB wrote:I use a RemStar Plus cpap system. I wanted to use the cpap on my boat when I sleep overnight. I called my local medical supplier and they stated the DC power cord would run about $80. I told them to keep the cord.

I went to Radio Shack and purchased a heavy duty (5 amp) DC power cord with the cigarette lighter attachment on one end and a plug (with tip being positive) for the other end. I plugged in the unit and it lit up. Did a quick startup and the unit seemed to work.

When camping out on the boat a few nights ago, I plugged in the machine and set up for a good nights rest. A few minutes after running, the machine lite up a couple of times and then stopped. I looked at the display and a code E36 (I believe, I was very tired) was displayed. I disconnected the power cord and reconnected it. The machine ran for a minute and then quit again.

First, I assumed the plug should have a positive tip and negative ring, but, is this correct?

Second, what is the DC voltage range of the cpap?

Third, does anyone have a list of error codes for the RemStar Plus?

I searched the internet and found a note about DC power cords. It stated that certain Respironics cpap machines will not work above 11 cm H20 using the DC source.

So, I adjusted the pressure to 11 cm from the originally setting of 12 cm and the machine seems to work. I don't know if the information is true. Does anyone know about limitations using DC power?

Thanks for all your help.

"
Barry more info on your machine would be helpful. What "exactly is written in white letters across the top of your machine?

I also made a DC power cord for my bipap and have used it several times w/o any problems with pressures up to 20cm. I think the cord I chose is heavier but believe the pin center is positive. That makes me wonder if you have the integrated humidifier and if there is ANY chance that water got inside this machine?

Check here for codes -
viewtopic/t17622/Remstar-Error-Codes.html

Without a bunch more info on your particular machine -- In general the supply is 12V, center positive.
cpap.com has power adaptors for just about any machine; the Remstar cord I got was $24 or so. I was just too lazy to build one of my own......I have gone 1 night without my machine due to no power......NEVER AGAIN!!!! It's also the only night since I got my machine that I was non-compliant!!!
If you build your own, you can do a custom length to a 12V buss on the boat.....
During stormy weather here, I keep my machine on a DC supply (battery) all the time so if power goes out I won't lose my xPAP. When I am without power it's usually for an extended time (end of the road rural - in the Sierras), I'll usually fire up the generator to charge the battery about every 3 days or so.....Once the storm "danger" has passed, I'll go back to the standard AC into the brick.

Good luck
take care
cheers
goose

I have had this happen when both my husband and I are trying to use our M series APAPs in our motorhome when not plugged into "shore power" (110). He started his first and had no problems, but mine would run for 10 seconds and shut off. We've been having electrical issues with the motorhome and we surmise that the voltage of the house batteries was not high enough to run both machines at the same time. The monitor panel indicated that the voltage was less than 12 when we checked it with one machine running (11.2, I think). We have not yet taken the motorhome in for service, so we don't know if that's really the culprit yet. But...you might check the voltage of your battery and to see if you need some electrical work.

Hi again and thanks for the replies.

First, It's a REMstar plus, model number: 1005960.

Second, the power cord I purchased from Radio Shack is rated for 5 amps. The unit will draw a maximum of 3 amps according to the plate on the underside of the machine.

Third, I don't know what is inside the "official" DC power cord however from the photos I've seen, there may be power filters at both ends (capacitors and coils) to help smooth out power.

Question: Has anyone ever taken apart an official Respironics DC power cord or does anyone have a schematic?

Thanks again.

Low voltage will certainly cause problems but Barry has not yet ruled out water spilling inside machine either.

goose wrote:In general the supply is 12V, center positive.

In general it is whatever it is!

There is no standard, or even a solid practical convention, on plug wiring for the sorts of low voltage connectors used with electronic devices.

Which is why there are usually specific indicators on the wiring polarity located near the connectors, or on the power supply.

Cheers,

Bill

Hi Again,

Sorry, forgot to mention there is NO hudmidifier built in to the machine and no water got into the machine.

As I stated before, when I reduced the pressure from 12 cm H20 to 11 cm H20, the problem seemed to go away. I was wondering if anyone else had the same problem.

Thanks again for all your thoughts.

If the battery isn't fully charged, it's internal resistance will be higher and that will cause the voltage to drop as the current drawn increases, so I'd say it's almost certain that it was marginal at 11cm, and at the higher pressure to 12, the current drawn was higher, which dropped the voltage (to the CPAP), and caused it to shut down.

I am glad I found this forum. I do a lot of camping. Do cpap machines run well off power stations. Black and Decker, Xantrex, and Duracell make some that run around 100-200 bucks. Curious if any of you folks have used this type of device to power your machines?? If so, how many nights can you get off a single charge??

I use the Black & Decker 400 using the DC. No problems using it for a weekend trip. I did a test when I first got it to see how long it would last - AC alittle over 7 hours, DC I got 5 nights. Note this is without humidifier.

Pineapple wrote:I use the Black & Decker 400 using the DC. No problems using it for a weekend trip. I did a test when I first got it to see how long it would last - AC alittle over 7 hours, DC I got 5 nights. Note this is without humidifier.

Thanks PA,

That is the exact same unit I have been looking at (B&D). Big difference between ac and dc use wise. I wonder why?
I am looking forward to a great nights sleep out in the woods now!!! Plus we had some heavy winds last week that
knocked out our power. Having another power source when the lights go out is pretty comforting.

Do those units take long to re charge??

Thanks again for your response.

AC supply means the battery first has to drive the inverter and through that the CPAP. The CPAP then converts the power back down to DC as it runs on DC internally. DC operation is pretty much straight from the battery to the blower. I'd guess most of the inefficiency is in the inverter, but there will be losses in the power supply of the CPAP too. As far as I know, the Respironics have an external power brick - if it warms up while running, that heat is the extra power...

ColinP wrote:AC supply means the battery first has to drive the inverter and through that the CPAP. The CPAP then converts the power back down to DC as it runs on DC internally. DC operation is pretty much straight from the battery to the blower. I'd guess most of the inefficiency is in the inverter, but there will be losses in the power supply of the CPAP too. As far as I know, the Respironics have an external power brick - if it warms up while running, that heat is the extra power...

Some Respironics are completely DC and require the brick with the inverter for AC, both the humidifier and the flow generator. My hubby and I both have M series and we made sure we got the newer humidifiers which are DC. When we use the motorhome power or battery back like the Black and Decker one described above, we unplug the AC brick with the inverter and plug the DC cord directly into the humidifier. We could choose to forego the humidifier and we may have to do that in the motorhome if we can't get our existing electrical problems fixed. Although I don't want to...my nasal passages get very dry and very plugged without humidification.

CorgiGirl wrote:

ColinP wrote:AC supply means the battery first has to drive the inverter and through that the CPAP. The CPAP then converts the power back down to DC as it runs on DC internally. DC operation is pretty much straight from the battery to the blower. I'd guess most of the inefficiency is in the inverter, but there will be losses in the power supply of the CPAP too. As far as I know, the Respironics have an external power brick - if it warms up while running, that heat is the extra power...

Some Respironics are completely DC and require the brick with the inverter for AC, both the humidifier and the flow generator. My hubby and I both have M series and we made sure we got the newer humidifiers which are DC. When we use the motorhome power or battery back like the Black and Decker one described above, we unplug the AC brick with the inverter and plug the DC cord directly into the humidifier. We could choose to forego the humidifier and we may have to do that in the motorhome if we can't get our existing electrical problems fixed. Although I don't want to...my nasal passages get very dry and very plugged without humidification.

I would need my humidifier also. I just signed up today on this forum. I will be checking out my machine a little closer tonight. I have been sleeping with a Cpap the last three years or so. Just got a new machine and mask. I have always done with out when camping. Now trying to find away to make it work when camping with no power outlets or during power outages, which have been frequent lately. My machine is currently set on 15. It seems that draws more power too.