CPAP while Boondocking

[jamesaye]

Help, CPAP when Boondocking

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I have to use a continuous positive airway pressure (CPAP) machine to help with my obstructive sleep apnea. It increases air pressure in my throat so that my airway doesn't collapse when I breathe in while sleeping.

We are full-timers in our 2005 Holiday Rambler Scepter, Roadmaster chassis, 400 HP ISL Cummins diesel with a ONAN 8 kw Generator. While on the road, we do not always have 115v ac unless in a FHU site or if I chose to run my Onan generator. I need 115 vac to run the CPAP machine, because it plugs into my 115vac outlet.   The back plate of the machine is marked 24 vdc, and 3.75 amp so it must have an inverter in it. 

Can anyone tell me 1. if it is safe to plug in an after market Power Drive, 750 Watt DC to AC Power inverter to my coach 12 vdc accessory system so I don't have to run the generator all night? 2. If I plug in the inverter and use it to run the CPAP,  is the wire from the battery bank to the accessory fitting sufficient to handle the CPAP current load all night (abt 8 hrs.)? 3. Assuming my coach batteries are fully charged and operating properly, will the CPAP machine draw too much current and drain them dead with overnight use?  4. Is the CPAP machine too small a load for the generator if I choose to use it for power and that is all I am running while asleep?

If anyone has any suggestions or ideas on how to safely accomplish this medical need while on the road, I would be very grateful for your input.

Cordially, James

[blakeloke]

James....you should already have an inverter on your rig.  Is it enabled from the Xantrax control panel?

Blake

[jamesaye]

Thanks Blake.  Yes I do have a Xantrax inverter installed in the coach.  Are you saying I will have 115 vac available from the Xantrax at my outlets even when I am not plugged in to an external power source?

[wolfe10]

2 hours ago, JamesAye said:

Thanks Blake.  Yes I do have a Xantrax inverter installed in the coach.  Are you saying I will have 115 vac available from the Xantrax at my outlets even when I am not plugged in to an external power source?

 

Correct.

You will need to verify that the outlet you want to use IS one powered by the Xantrex inverter/charger.

And, if not, it would likely only require a little re-wiring.  Let us know if you need assistance with advice on this.

[blakeloke]

James....yes.  You should have 115 vac to your outlets.  Once you have "enabled" the inverter from the control panel you should be good to go unless there is a tripped breaker.  We can help you with useable power but need a bit more information.  

Wattage of your inverter (ie:2,000w)

Size and number of "house" batteries and condition (age)

Amps or watts of your CPAP machine.

I've upgraded my inverter but our coaches are very similar.  Originally I had a 2,000w with 2 -12v deep cycle batteries.  With this setup I could run our furnaces all night and have enough power to run the TV for a few hours before bed.

Currently I have a 3,000w inverter with 4-6v batteries.

You should be able to set your control panel to auto start your generator when your batteries get down to a preset level.  For example @ 55%.

If you don't have the owner's manual I bet I can dig up ours and mail it to you.

Blake

 

[jamesaye]

Ok, great.  On the issue of draining the batteries with this load and the current carrying capacity of the installed wiring, any comments?

[wolfe10]

James,

Yes, we need this information to give you sage advice:

Size and number of "house" batteries and condition (age)

Amps or watts of your CPAP machine.

Also, what other electrical needs will you have (both 12 and 120 volt) AND, for how long (single over night or longer term dry camping)?

[jamesaye]

Blake, 

In answer to your questions:  I have the 2000 w Xantrex inverter that came with my coach, 4 - 12 v house batteries and seem to be in good shape, they are about three years old.  The CPAP back plate shows 3.75 amp, which is I assume is what it draws when in use.

Brett,

The only real concern is being able to use the CPAP overnight when sleeping.  I believe the only other electrical needs would  be lighting.  The refer is both AC and Propane, so without an AC input it automatically switches to propane.

[kaypsmith]

4 hours ago, JamesAye said:

The back plate of the machine is marked 24 vdc, and 3.75 amp so it must have an inverter in it. 

Is there an adapter that plugs into the wall and a cable from that adapter to the cpap machine? If so it sounds like a power supply (converter from 120 volt ac to 24 volt DC).

[desertdeals69]

If your refrigerator has an automatic switch that goes to ac when current is present, switch it manually to propane because it draws a lot of current on ac when the inverter is on.

[wolfe10]

2 hours ago, desertdeals69 said:

If your refrigerator has an automatic switch that goes to ac when current is present, switch it manually to propane because it draws a lot of current on ac when the inverter is on.

True, IF, repeat IF the refrigerator is plugged into an inverter-supplied outlet.  Most are not.

But agree with Bruce-- you need to VERIFY:

Turn inverter on.

Disconnect from shore power/generator off

Is there power to the outlet the refrigerator and/or ice maker is plugged into?  If so, you will need to manually verify that neither refrigerator nor ice maker (if so equipped) are running on 120 VAC.

[rossboyer]

You probably have a ResMed cpap machine. They have a 12v dc to 24 v dc for the cpap. I suggest you install a standard 12 v dc outlet like those used for cigarette lighters. You will use a little less power since the inverter does have about 10% loss. I found a 12 v dc circuit under our bed that was 20 amp fused, but had less than 1 amp intermittent load. 

[jamesaye]

I think I'm getting a bit confused.  The ResMed CPAP machine does have a standard 115v ac plug on one end of the power cord.  The other end has a small round male fitting that looks like a computer power input cord.  Since the back plate/label indicates 24 vdc,  3.75 amps, I presumed that the ResMed machine must convert the 115v ac into the label annotated 24 vdc.  Now that I have been told that the inverter,  when turned on and properly set up, supplies 115vac to selected circuits.  I will use a circuit tester to check the coach for which outlets are so powered, and use one of them for the occasional CPAP boondocking needs.  Many heart felt thanks to all who responded 

Cordially, James 

[hermanmullins]

James,

Like so many power supplies your uses 110 vac to provide the correct dc volt for your CPAC. If you have a concern you can always add two more batteries (space permitting) and a dedicated inverter just for your CPAC.

Herman 

[jamesaye]

Thanks Herman.  I am in the process of circuit testing each of my 115vac outlets.  Once identified I will mark them for future use.  "Fair winds and following seas" back at ya

from a Mustang.

[rossboyer]

You are correct that the ResMed comes with 120v ac to 24 v dc power supply, but you can order a 12 v dc to 24 v dc power supply. I have one of each. 

[jamesaye]

Thanks Ross!  That's very Interesting, I didn't know that.  I will look into the possibility of getting one as a viable possibility.  I can't believe how much I've learned for so many wonderful folks.  Talk about what a great community to be part of  

 

[kaypsmith]

You can also use two 12 volt batteries wired in series to produce 24 volts as your power supply, just need the proper end to plug directly into the cpap machine. But the 12 volt converter sounds like a very good choice.

[hermanmullins]

3 hours ago, JamesAye said:

"Fair winds and following seas" back at ya from a Mustang.

Do we need to let the others guess what, other than a horse, a Mustang is?☺

Herman 

[wildebill308]

4 hours ago, JamesAye said:

Thanks Herman.  I am in the process of circuit testing each of my 115vac outlets.  Once identified I will mark them for future use.  "Fair winds and following seas" back at ya

from a Mustang.

I bet only certain circuits are powered by your inverter. With the refrigerator on propane and not running the furnace I think you should be good for at least 10 hours.  Without knowing how good (ampere hour) and at what charge your batteries are starting at that is as much sage advice I can give. Add the usual "your results may vary"

You could do a test run during the day to see how long the batteries will last.

Bill

[manholt]

Non-Com, who becomes a Warrant Officer

[wayne77590]

Not necessarily a Warrant Officer, could go straight to Second Lieutenant and up the chain.  One example, General Al Gray, USMC (Ret) Commandant Of The Marine Corps. He enlisted in the Marine Corp, rose to the rank of Sergent and hen commissioned a Second Lieutenant. That makes him a Mustang. Many others have done the same.

Back on topic. ResMed makes DC supplies that work directly off of DC instead of converting down to DC from AC. 

What series ResMed do you have?  I have a series M (I thing - been a long time I looked at it) but we have not boondocked so I'm always plugged int 115vac. I had the option to get 12vdc but did not take it.  Next MH I may consider doing so.

[rossboyer]

I do not remember which ResMed I have and it is in the motor home as a spare. After 5 years I got a Philips that is 12 v dc; therefore, I have the 120 ac power supply and a cigarette lighter male plug and connection directly into the CPAP.  In the sticks and bricks I use the 120 v supply and the 12 v dc cord in the motor home. 

[jamesaye]

To All in this community, THANKS.  I did a dry run and identified the inverter supplied outlets.  Problem Solved.   I will now use the Inverter to supply power when I'm on the road or boon-docking.  I do hope my question followed by all the great answers, provides some help to others that have to motorhome with medical devices.  You were all great - many thanks.  Fair winds and following seas to you all . . . speaking of seafaring,  I was a Mustang in the Navy by virtue of going from Seaman Recruit to Master Chief Petty Officer and after receiving a commission (different from Warrant) I managed to go from Ensign to Commander.  Had a career that was almost as much fun as RVing.  OH, and I don't kneel for the national anthem !

P.S. Wayne77590, so sorry for your loss from Harvey, my wife Pat and I will continue to keep you and  the whole community in our prayers.  Semper Fi

[blakeloke]

Great news James!

Thanks for the follow-up.

Blake