My old RV had invertor output next to the bed, the new one does not and there is no handy spot to tap 12V. My idea is this. Buy a 120V relay with double throw 120v contacts. Remove the 12 volt feed from the back of the convertor that feeds the bed plugs. Buy a 1000 watt invertor and wire it through the relay such that when there is 120v shore power, the relay powers up and switches 12Ov to those plugs. When 120v is not present, the relay goes to its resting position and switches 120V output form the invertor to those plugs. The 2 bed plugs are on their own circuitI have plenty of room behind the convertor box to accomodate the relay and the invertor.Anyone see an issue with this?

If 'resting position' is with the other contacts closed, that will work.It would be easier and likely safer to just keep the inverter on battery 24/7. When shore is present it will be charging batteries.

Are you sure you need the inverter? My CPAP runs on 12V, although I did have to buy a special !2V cable for it. I'm new to CPAP, but have read that most of them run on !2V; 12V is produced by the big block thing on the 120V cord that comes with the machine. By running straight from 12V, you are cutting out the inefficient middleman, the inverter.

Sounds like an awful complicated solution to what may be a simple problem. Most CPAPs sold today operate on 12vdc or 24vdc. Both have an adapter/plug that allows operating from a 12vdc circuit.If your CPAP is one of them, buy the 12vdc adapter and plug into the 12vdc system of your RV. What voltage does your CPAP really need? Look at the label on the back.

and if you use a pass over humidifier, rather than a heated one, your power needs will be minimal.bumpy

I misread your post, so I deleted my answer...I thought you NEEDED 12 volt power near your bed, but you actually need 120 volt power near your bed. Can you not just run an extension cord from one of the other 120 volt outlets in the trailer?

CPAP and battery power | Good Sam Community

2oldman
Explorer II
May 05, 2014
If 'resting position' is with the other contacts closed, that will work.

It would be easier and likely safer to just keep the inverter on battery 24/7. When shore is present it will be charging batteries.
Tiger4x4RV
Nomad
May 05, 2014
Are you sure you need the inverter? My CPAP runs on 12V, although I did have to buy a special !2V cable for it. I'm new to CPAP, but have read that most of them run on !2V; 12V is produced by the big block thing on the 120V cord that comes with the machine. By running straight from 12V, you are cutting out the inefficient middleman, the inverter.
beemerphile1
Explorer
May 05, 2014
Sounds like an awful complicated solution to what may be a simple problem. Most CPAPs sold today operate on 12vdc or 24vdc. Both have an adapter/plug that allows operating from a 12vdc circuit.

If your CPAP is one of them, buy the 12vdc adapter and plug into the 12vdc system of your RV. What voltage does your CPAP really need? Look at the label on the back.
Bumpyroad
Explorer
May 05, 2014
and if you use a pass over humidifier, rather than a heated one, your power needs will be minimal.
bumpy
Nvr2loud
Explorer II
May 05, 2014
I misread your post, so I deleted my answer...

I thought you NEEDED 12 volt power near your bed, but you actually need 120 volt power near your bed. Can you not just run an extension cord from one of the other 120 volt outlets in the trailer?
oughtsix
Explorer
May 05, 2014
My CPAP is 120v only so I purchased a barely used Respironics RemStar off of Craigslist for $125. It uses a 12v brick power supply. I used a RadioShack 12v universal power supply with the interchangeable tips. Works perfect! Much better than doing a whole bunch of wiring and doesn't pull as much current of having an inverter in the mix.
jaycocreek
Explorer II
May 05, 2014
12 volt here also.I have a seperate battery, size 27, I use for the cpap only.I do use an inverter for things, but not on the cpap
bluie5
Explorer
May 05, 2014
I used mine with an inverter plugged into the 12v jack an then an extension cord to my machine. With my new rig I'm going to get the 12v plug for it and tap into a light and put a 12v jack on my side of the bed. The fan on my inverter ran constantly so hopefully with using just the 12v now it will save some juice.
oughtsix
Explorer
May 05, 2014
I used an Optima Yellow top battery for tent camping with my CPAP the past few years. I could easily go 4 nights and have plenty of juice left in the Optima. Last weekend was my first trip in our new trailer. I sleep much better with the trailer around me and a real bed under me. We were tethered so I just used the 120V to 12v brick. I will be using the Respronics on 12v when we are dry camping though.
Timothy
Explorer
May 06, 2014
Or you could just use a standard 3 way light switch and select your power source manually. Wire the outlet to the common terminal on the switch, normal power feed to one terminal and invertor feed to the other. Be careful to choose an inverter that will meet the power quality requirements of the cpap.

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