Worth Buying DC Conversion Kit for CPAP?

[DT6]

We have been running our CPAP machines when we sleep in our 19, and now our 21C off the inverter. I just noticed that ResMed (current brand of CPAP we have) sells a DC Power Converter for the machine.

I had Escape stub DC wire in the overhead cabinets, so I'm assuming I can add two "cigarette lighter" plugs and run the CPAP from that. The question (again assuming I can add two plugs to the same line) is - is it worth it? The DC Converter for each is $95, so essentially a $200 investment to run these every night DC instead of AC from the inverter.

[TTMartin]

Originally Posted by DT6

We have been running our CPAP machines when we sleep in our 19, and now our 21C off the inverter. I just noticed that ResMed (current brand of CPAP we have) sells a DC Power Converter for the machine.

I had Escape stub DC wire in the overhead cabinets, so I'm assuming I can add two "cigarette lighter" plugs and run the CPAP from that. The question (again assuming I can add two plugs to the same line) is - is it worth it? The DC Converter for each is $95, so essentially a $200 investment to run these every night DC instead of AC from the inverter.

Yes and no.

Yes, it is worth it to run your CPAP on 12 volt DC.
However the DC 'Converter' may not be worth $95. I purchased the similarly priced genuine 12 volt cord for my older Phillips CPAP (recalled), and it turned out to be just a straight through 12 volt cigarettes plug with just two magnetic ferrites and zero electronics. I sent it back and made my own for about $10.

Before you shell out $95 for a $10 cord take a look at your 120 volt to DC box and see what the output voltage is. If it is 12 volts you don't need to spend $95 per cord.

This cord works with my Breas Z2 Travel CPAP that I purchased when the Phillips was recalled while I am waiting for a replacement.

JacobsParts 12V DC 5.5mm x 2.1mm Car Cigarette Lighter Power Supply Adapter Cable (10 Feet)

I only have one outlet by my bed so I normally use the 2.5 ft version and have the longer one in case I have to sleep with my head at the other end of the bed if I'm not level (i.e. Walmart parking lot overnight).

Edit: It does look like the ResMed is more than a straight through 12 volt cord. However here is a 3rd party cord for $33 on Amazon.

KFD DC Adapter Car Charger for Resmed S10 Series,ResMed Airsense 10 S10 AirCurve 10 Series CPAP and BiPAP Machine,90W Resmed S10 370001 37297 Rockpals 300W/500W Vehicle Power Supply Cord Cable Charger

[Randy in Maine]

I also have the Res Med 12 volt plug in for mine. I use it even when the trailer is plugged into shore power with no issues.

[emers382]

Your resmed is likely 24 volt so a "straight through" 12v cord as suggested is likely not going to work.

Our ResMed Airsense is 24v. for which we bought the converter 12-24v for about $80 and is ideal since we don't have an inverter. Fortunately our new-to-us had a 12v plug right at the foot of the bed on the side we needed it.

[TTMartin]

Originally Posted by emers382

Your resmed is likely 24 volt so a "straight through" 12v cord as suggested is likely not going to work.

That is correct it is not a straight through 12 volt cord. I indicated that in my edit.

Originally Posted by TTMartin

Edit: It does look like the ResMed is more than a straight through 12 volt cord. However here is a 3rd party cord for $33 on Amazon.

KFD DC Adapter Car Charger for Resmed S10 Series,ResMed Airsense 10 S10 AirCurve 10 Series CPAP and BiPAP Machine,90W Resmed S10 370001 37297 Rockpals 300W/500W Vehicle Power Supply Cord Cable Charger

They don't need to pay $95 for the ResMed cord a $33 dollar 3rd party cord is available.

I left the part about a straight through 12 volt cord as that applies to many other CPAPs and it may apply to someone coming across this thread in the future.

[DT6]

Thanks for the suggestions! I'm going to give the $33 referenced one on Amazon a try as I can return it easily. It is not clear from the picture that it will work with a ResMed, By that I mean the ResMed CPAP has an odd looking power plug, looks something like a USB2. If this works, it will be nice to not have to run the inverter all night.

[BigSwede]

I have been using a CPAP for over 20 years, and I have always made sure I had a machine that runs on 12 volts in addition to 120V. It greatly simplifies camping, whether tent, camper, or in vehicle. No need for voltage converters or expensive proprietary battery packs.

[mfschu]

Any idea how many amp hours a Resmed will draw overnight (with the humidifier off)? Thanks!

[Randy in Maine]

I found this online....for what this is worth.

The formula is this: Note: (Wh) = Watt Hour.
My CPAP (Air Sense 10) draws 9-15 watts. Heater and humidifier off.
AC = 240 (Wh) x .85 / wattage used. So, 240 x .85 / 15 watts = 13.6 hours.
DC = 240 (Wh) x .95 / Wattage used. So, 240 x .95 / 15 watts = 15.2 hours.

That being said my Res Med 10 (heater and humidifier off) performed quite well with my 190 solar charger and my 2x6 volt batteries. Never an issue.

[joebuoy]

When I tent camped I used a portable Lithium Battery rated at 400 Wh/120,000mAh. Using my Resmed AirSense 10 I got the following results before the battery was down to 20%:

Heated hose and humidifier: using 120V AC - 7 hr 30 min hour, using 12V DC - 14 hours

Unheated hose and humidifier: using 120 V AC - 13 hr, using 12v DC - 19 hr.

Unheated hose and no humidifier: using 120 V AC - 30 hr 30 min, using 12 V DC - 45 hr 30 min

My notes say (I'm not sure if this is for 120 V AC or 12 V DC:

Heated hose and humidifier is about 20 W per hour
Unheated hose and humidifier is about 9 W per hour
Unheated hose and no humidifier is about 6 W per hour

[DT6]

ResMed also posts charts that show expected electrical consumption rates, on their website. However, as I recall I could not find it if I went to their website directly. I did a google search for "ResMed CPAP Power Consumption Charts" and was able to find it easily:

https://document.resmed.com/document...de_glo_eng.pdf

[mfschu]

Excellent information! Thank you both! I'm going to give the $33 version a try.