Bi-PAP battery question - why is this cable SO expensive?

Can anyone explain why a Respironics Bi-PAP machine needs this specific and VERY expensive cord in order to run on DC?

https://www.cpap.com/productpage/DC-Pow ... Bipap.html

What special need is there that requires a $165 cord instead of a $25 one?

Thanks,
Tony

Hi,

Well, it is medical equipment after all. Dittos for the CPAP machine. Its just a fan, yet my BiPAP costs over $1000 new. In the case of the DC power, you might be able to get a real nice pure sine wave inverter for far less, and the inverter will run you humidifier, too. An inverter is less efficient than running directly off of DC power. If you have the battery power to spare, it might work for you. If you are very limited on battery power, you might want to go the DC adapter route.

-john-

tonycog wrote:Can anyone explain why a Respironics Bi-PAP machine needs this specific and VERY expensive cord in order to run on DC?
https://www.cpap.com/productpage/DC-Pow ... Bipap.html
What special need is there that requires a $165 cord instead of a $25 one?
Thanks,
Tony

You'd have to ask them. I have one but also made one with parts from Radio Shack.

As far as electricity, I know nothing. I just wondered if there is some special, whiz-bang circuitry that makes this cord 6X more expensive than the same cord for a CPAP. This AC/DC stuff is driving me crazy.

Tony

If you look at the next picture you see this is more than just a cable. I think this is a device that takes the voltage from
the car battery and provides 12Vdc. Well isn't a car battery 12v you might ask. No. When the engine is running in a car it
may go up to 14.8v, then it's 13.6v when you switch the engine off and by the time it looks like your battery is running down
is probably ~10v. This device may reduce the battery voltage if too high and boost it if too low. That is one possibility.

It's because the BiPAPs run on 24V DC, not 12V DC:

Electrical
- DC Voltage Source 24V (when operated with the external DC power adapter accessory)
- DC Current 3.0 A maximum

(That comes from here: https://www.cpap.com/cpap-machine/bipap ... ifications)

So you'll notice the block in the picture as well as the cable. This would be what's transforming the 12 volts to the required 24.

blarg wrote:It's because the BiPAPs run on 24V DC, not 12V DC:

Electrical
- DC Voltage Source 24V (when operated with the external DC power adapter accessory)
- DC Current 3.0 A maximum

(That comes from here: https://www.cpap.com/cpap-machine/bipap ... ifications)

So you'll notice the block in the picture as well as the cable. This would be what's transforming the 12 volts to the required 24.

Thanks. That helps. But I checked the specs for the Bi-PAP AutoSV and it says this:

https://www.cpap.com/cpap-machine/bipap ... -cpap.html

"12VDC (when operated with the external DC power adapter accessory)"

But they still call for the expensive cord for it, just like the Bi-PAP you referenced. So I'm still puzzled that the cord they want me to buy is 6X more expensive.

Thanks,
Tony

tonycog wrote:

blarg wrote:It's because the BiPAPs run on 24V DC, not 12V DC:

Electrical
- DC Voltage Source 24V (when operated with the external DC power adapter accessory)
- DC Current 3.0 A maximum

(That comes from here: https://www.cpap.com/cpap-machine/bipap ... ifications)

So you'll notice the block in the picture as well as the cable. This would be what's transforming the 12 volts to the required 24.

Thanks. That helps. But I checked the specs for the Bi-PAP AutoSV and it says this:

https://www.cpap.com/cpap-machine/bipap ... -cpap.html

"12VDC (when operated with the external DC power adapter accessory)"

But they still call for the expensive cord for it, just like the Bi-PAP you referenced. So I'm still puzzled that the cord they want me to buy is 6X more expensive.

Thanks,
Tony

Tony the reason is that that particular bipap runs on 24dc. When I got my Bipap I was going to get a Remstar pro2 Auto Bi-Pap but I got the M-series Bi-Pap Auto because it ran on 12vdc not 24vdc.

Some of the older machines may have been 24v but ALL of the machines I have had are 12v and will use the very same cable I made. It does absolutely nothing to the power - btw. It does have a ferrite core on it to filter out the noise it makes so it won't bother your car. But if you are using it on a battery the homemade one is fine as long as the wire is large enuff to carry the current it requires.

Why? Why not? My DC Cable allows me run a cheaper battery that last's longer. Overall, I've saved money.. Cha ching!!

Some of the copy writers have been known to play loose with the facts.
The sv and st models are still made up on the tank machines and require 24 vdc. The M series are able to run
on 12 vdc and do not require the special cable.

I have remstar plus 12 VDC
" remstar plus with cflex 12VDC
" remstar auto with cflex 12 VDC
" remstar bi-pap with bi flex a seperate 24 VDC Power converter hanging off the back.
It just takes more power to run the tank bipaps..

Long live the tank and I hope Blarg does not fall off the world living down under.

allen

For the record, I just looked at the underside of my Bi-PAP. It says that it runs on 24 volts. It frustrates me that the copy writers can't even get this straight on a $4000 machine.

I'm through fussing with this. It's much too confusing for an electric novice. I'm buying an AGM deep cycle battery and a pure sine wave power inverter. The total price won't be much different than the $400 + I'd spend by buying all the official battery packs, etc. plus I can use it to power other things as well, if needed.

Thanks to all for your input and help.

Tony

tonycog wrote:It frustrates me that the copy writers can't even get this straight on a $4000 machine.

Since it will indeed run off a 12V DC supply if you use the Respironics external DC power adapter accessory as clearly stated... what is not "straight" here?

Cheers,

Bill

That is way over priced, I can help I am an electrical engineer by trade, and I went to radio shack for an 12 vdc to plug to power my cpap machine, yes the 12 vdc does change under load, and rise when the engine is running, but I do not beleive they are regulating the voltage, do you have a picture of the cpap machine where you plug into to power from a battery.

billbolton wrote:

tonycog wrote:It frustrates me that the copy writers can't even get this straight on a $4000 machine.

Since it will indeed run off a 12V DC supply if you use the Respironics external DC power adapter accessory as clearly stated... what is not "straight" here?

Cheers,
Bill

The text on the CPAP.com site claims that it is 12V. The machine says it is 24V. That is not straight. The original question I asked was about the ridiculous price for this specific cord, when other cords for Respironics machines are about $25.