Go Back   iRV2 Forums > iRV2.com COMMUNITY FORUMS > iRV2.com General Discussion
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
Thread Tools Search this Thread Display Modes
Old 03-03-2015, 06:29 PM   #1
bdwillie's Avatar
Thor Owners Club
Join Date: Nov 2012
Posts: 54
Boondocking with a CPAP

My wife has just received her first CPAP machine so I have a question. We like to boondock. I am thinking of adding a separate battery just for a small inverter to run her CPAP machine. I am thinking of using a battery isolator so that the RV converter, and tow vehicle can charge the second battery, but nothing from the RV could draw from it EXCEPT the CPAP inverter. Anyone here wire an isolator in for two batteries? Or any other ideas to help settle the wife's fear of the battery draining while using the heater and such in the coach??

Bob & Kimi, Fuzzy Butted Daughter Penny
2012 Crossroads Cruiser CF27RLX
2000 Ram 2500
bdwillie is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 03-03-2015, 06:31 PM   #2
Community Administrator
Clifftall's Avatar

Fleetwood Owners Club
Ford Super Duty Owner
Join Date: Aug 2009
Posts: 24,519
Here's a link to previous threads that may assist.



Cliff,Tallulah and Buddy ( 1999-2012 )
Clifftall is offline   Reply With Quote
Old 03-03-2015, 06:32 PM   #3
bdwillie's Avatar
Thor Owners Club
Join Date: Nov 2012
Posts: 54
Thanks! Will check it out!
Bob & Kimi, Fuzzy Butted Daughter Penny
2012 Crossroads Cruiser CF27RLX
2000 Ram 2500
bdwillie is offline   Reply With Quote
Old 03-03-2015, 06:38 PM   #4
Senior Member
JFNM's Avatar

Newmar Owners Club
Solo Rvers Club
Join Date: May 2013
Location: Mountain West
Posts: 1,060
Originally Posted by bdwillie View Post
I am thinking of adding a separate battery just for a small inverter to run her CPAP machine.
Hi Bob,

The first thing to check is whether the CPAP is 12V. Many of them are. If so, all you need is the appropriate plug wired into your 12V house system - no need for an inverter.
JD & Buddy (the ferocious feline) - Full timer out west
2005 Newmar Dutch Star 4023 | 2010 Wrangler (daJeep) | 650 Watts Solar
My Adventures
JFNM is offline   Reply With Quote
Old 03-03-2015, 06:40 PM   #5
bdwillie's Avatar
Thor Owners Club
Join Date: Nov 2012
Posts: 54
Unfortunately, her's is a 24 volt model
Bob & Kimi, Fuzzy Butted Daughter Penny
2012 Crossroads Cruiser CF27RLX
2000 Ram 2500
bdwillie is offline   Reply With Quote
Old 03-03-2015, 08:07 PM   #6
Senior Member
Fred and Bonnie's Avatar
Workhorse Chassis Owner
Join Date: Jan 2002
Location: Pacific Northwest or SoCal
Posts: 2,662
Send a message via ICQ to Fred and Bonnie
Originally Posted by bdwillie View Post
Unfortunately, her's is a 24 volt model
2X12V in series?

Fred and Bonnie
2005 Dolphin LX 6375
Abby, Ruffles & Scarlett, "The Cats"
Fred and Bonnie is offline   Reply With Quote
Old 03-03-2015, 08:28 PM   #7
Senior Member
Join Date: Sep 2012
Posts: 4,035
There are 12 to 24 switching converters available. How much power does it draw? That is the first question for everything else.
nothermark is online now   Reply With Quote
Old 03-03-2015, 10:26 PM   #8
Senior Member
sknight's Avatar
Appalachian Campers
Join Date: May 2009
Posts: 908
My CPAP is 120V only, an oversight on my part when I got it.

I have a 1200W inverter that I plug it into, on the 12V side I found that it draws in the 5A range when running with the humidifier on high so one battery could easily handle it overnight (5A times 8 hours = 40 amps, under the 50% point of most deep cycle batteries). I converted mine to four 6V batteries and just wired the inverter directly to the output of my battery switch.

How you patch yours in is up to you, you could do a simple switch to isolate it from the rest but you'll have to remember to flip the switch. I'm sure you could come up with an automatic setup that is powered when the converter is plugged in to shore power but if it were me I'd just add an extra battery (Or three. I love my setup.) and just wire it in.

If you have the space to go the four battery route I whole heartedly recommend it. I can spend the evening watching TV, running lights, water pump, etc, sleep through the night with my CPAP, iPad and phone charging, furnace keeping the interior 50* in 19* weather and wake up to the voltage at 12.3-12.4V or 70-80% SOC. My converter would reach float mode in less than two hours on the generator, frankly if I was miserly with my power I bet I could make two days without charging and three without the furnace going.
2001 HO Cummins powered Dodge 2500
2014 Sierra 346RETS
Nights camped in 2014-28
sknight is offline   Reply With Quote
Old 03-04-2015, 06:16 AM   #9
Senior Member
Join Date: May 2013
Location: North Central Vermont
Posts: 811
You can buy one or two 35AH deep cycle batteries. If her CPAP is 24v, you could wire two in series on the closet floor. They are smaller & lighter than house batteries. Get the AGM type so you don't have to worry about venting. They run $65-70 on Amazon. You could also get a 30-80 amp solar kit to charge it (them with). Of course upgrading your house batteries and adding solar or generator could take the worry out of depleting your house batteries.
I used a large portable jump start battery for my first boondocking with a CPAP. It went dead the middle of the second night and needed two days on 120v to recharge. Learned my lesson on start vs deep cycle then.
2015 F350 XLT PSD CCSB SRW, Andersen Ultimate hitch
'12 Cougar High Country 299RKS, Mor/Ryde Pinbox
1/77 Armor Bn, 5th Mech, I Corps
SkiSmuggs is offline   Reply With Quote
Old 03-04-2015, 07:03 AM   #10
Senior Member
Ron_H's Avatar
Newmar Owners Club
Join Date: Apr 2014
Location: White Rock, BC
Posts: 533
I have used a CPAP for the past 15 years so, after wearing out my original machine, I've had the opportunity to buy another and utilize the experience I have gained.

Has your wife tried using her CPAP without a humidifier? Some folks require one and others don't. i was provided with one when I started out but eventually I was forced to try going without it when travelling light for business. I then found that I really didn't need it. If she can go without the humidifier you can greatly reduce the power requirement as the heat element is the greatest power draw.

If finances allow you can also look at more power efficient models and accessories for travel. My pressure requirements are significant so I purchased a second portable unit for travel and it is ideal for motorhome travel. It draws very little power and can even be run from a small rechargeable li-ion battery that fits in the palm of your hand.

This is the model I have but there is another portable unit available now that is even more compact and uses a small li-ion battery. CPAP.com - Transcend Travel CPAP Machine

My full-sized 120 volt unit also works fine in our MH running off the inverter. It and the loss to the inverter show a combined draw of 3 amps.
Retired and livin' the RV dream!
2005 Newmar 43 ft. MADP, Cummins ISL 400HP, 2008 Honda CR-V toad
Ron_H is offline   Reply With Quote
Old 03-04-2015, 01:32 PM   #11
Join Date: Feb 2015
Location: Texas
Posts: 49
I bought a 2nd cpap(12V) just for the RV.I got a factory reconditioned from my local respritory therapist for less than half of the same model new.
1960C182 is offline   Reply With Quote
Old 03-07-2015, 03:11 AM   #12
Senior Member
Beak12's Avatar
Winnebago Owners Club
Join Date: Oct 2014
Location: San Diego, CA
Posts: 106

Wish I could use the proper terms but alas! Have used a cpap for years. Have a old one in my RV. When I had a Trailmanor I had them install a 12v cig lighter next to my bed. At some point I got a adaptor that plugs in the cig lighter and my CPAP plugs into that. Works great.
I now have a used Itasca Navion 23H and I have to use the Cig Lighter that goes with the TV power button. So I now need a 6 foot extention cord and then I plug my CPAP into that. Use same adaptor that I used in my Trailmanor. Works fine. Just have to be careful not to get my foot stuck in the cords when I take the ladder in the middle of the night. LOL

PS: Never used it two night in row. Just one night in a parking lot.

PPS: When I was given my CPAP they said I could use it any place.. I have taken it to France--England--Germany-Holland All I needed was the correct Elec Plug for the country I was in. Never had a problem.
Beak12 is offline   Reply With Quote
Old 03-07-2015, 08:52 AM   #13
Senior Member
Join Date: Feb 2012
Location: Tucson
Posts: 146
Wink Aa dedicated DC outlet works for me

If you end up using an inverter be sure that it is a Pure Sine Wave model as many CPap's can be damaged by the use of anything less. When I got my CPap about 9 months ago I ordered a 12v power cord from the manufacturer. Then I hard wired a cigarette lighter outlet directly to the house batteries (with an in line fuse), near the head of our bed.

This works well and even on nights when the furnace runs intermittently (my CPap has a humidifier), the two group 27 batteries handle the load without a problem. Always nice to have another DC outlet available as well. Works for me.

2012 Nexus Phantom 23P Class C
Ford E-350 Chassis 6.8L V-10 w/5 speed trans w/tow haul mode, 55 gal fuel tank
USCG Licensed Master 100 Ton (Retired)
Capt Steve is offline   Reply With Quote
Old 03-07-2015, 12:22 PM   #14
Senior Member
Damon Owners Club
Workhorse Chassis Owner
Join Date: Mar 2009
Posts: 21,176
There is an easier method... Get a 12 volt CPAP. Yup, they make 'em that are designed to work off automotive battery power in the event of a failure.

Next you need to knwo how much power that blower sucks overnight, Recommendation, plug it into a Kill-a-watt and ask it for watt hours.. Post results (Actually PLEASE do this I would really like to know, In fact PM me with them if you can (and post public as well) I'll do the math and tell you how much battery it needs.

Home is where I park it!
wa8yxm is offline   Reply With Quote


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Cost of boondocking? Gannet Boondocking 67 02-14-2015 10:32 PM
Boondocking Report: Hannold Draw, Big Bend Nat'l Park RussOnTheRoad Boondocking 2 01-13-2015 02:23 PM
Boondocking Report: Feedback Requested RussOnTheRoad Camping Locations, Plans & Trip Reports 11 05-29-2014 09:51 PM

» Virginia Campgrounds

Reviews provided by

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 11:24 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.