RV Battery from Tow Vehicle 12V

We have a similar 2011 177 that was built January 2011 and picked it up in March 2011.  Has serengeti decals (no rings).  Still have one of the original batteries that was purchased April 2011, a 12v group size 24 deep cycle Interstate.  The other one was replaced last August with a 12v Trojan T-1275.  We simply use a multitester to make sure batteries don't go below 12.2v before recharging.  Normally boondock so batteries get a lot of usage.  Also we do not utilize either solar or generator.

After 11 years the only major thing to go bust was the Dometic fridge after 9.5 years as it developed an ammonia leak.  Replaced with the same model.  All is good for now.  Been a great dependable TT.

Again, more great information...once I get the trailer out of storage to somewhere I can do some work on it, it's something I will certainly consider an option.  Since the purchase, other than winterizing, I've barely had a chance to dig around...

Appreciate the info and offer.  I have a ResMed S9 I use for travel and I picked up a DC-DC converter for it as the factory is an AC-DC.   The DC-DC is pretty efficient, and when used with the humidifer/heated hose off, I should get some great run time according to their specifications.

Everyone...thanks so much for all the great info....I think I'll be splicing into the TV/stereo area as well which should work for me and a location to install a 12V plug etc.

When the vehicle is off, I'll need to test if V is supplied so as to not run down the battery.

On my Frontier, the vehicle's power shuts off. It seems to be on the same timer as the automatic off for the headlights and other lights. That is good in that I can be fairly sure that the starting battery in the Frontier won't be drawn down if I leave it plugged in.

Propane being so cheap and the system easy to manage, I think I'll be looking at that as the go-to for the fridge.  I do have a CPAP machine, so making sure I have solid 12V power for at least 6 hours every night is important to me...I've got a 200W solar suitcase setup, a small generator (if need be), and a DC-DC power supply for the CPAP which is much easier on the power usage (turning off humidifer etc), so should be OK.

What CPAP machine do you have? I have the Respironics Dream Machine. It uses 12V natively. If you need one, I have a spare 12V power cord that plugs into a standard 12V power outlet. When I purchased the 12V cord for my Dream Machine, I did not realize that it was the same as the one for my prior Respironics System One machine. If it would work for your machine, cover the postage and you can have it.

I'll swap out all the lights in the R-Pod for LED...what else uses DC in these?

Yes, swapping out the interior, the porch, and the hitch lights are the best bet. As for others, such as marker lights, they are only on when the vehicle is plugged in and the lights are on so they are not as important.  As for what else uses 12V power? Just about everything electrical uses some. The water heater uses 12V power for the control circuitry, even if you are using propane. The furnace uses 12V power for the fan and controls. The LP/CO detector constantly uses 12V and is hard wired and does not go through the fuse panel so it can't be turned off. If you have an electric jack, that uses 12V. The slide-out uses 12V. The refrigerator, even on propane, uses 12V for control and lights. The vent fan uses 12V. Still though, if you have an adequate setup (and it looks like you do), the 12V power usage should be okay for you to run your CPAP machine for multiple nights, especially since you do have a pretty good solar setup with generator backup.

What you can do is add a small voltmeter to monitor the battery state better than the panel lights can. You could also install a battery monitor to keep track of the amperage for charging and discharging and that will be even better than a simple voltmeter. I did that. You can look in my mods to see what I did for my LiFePO4 battery modification. There is a picture of the battery monitor I purchased and installed which is the AiLi Voltmeter Ammeter. You may need a Custom Cable for this monitor because the cable that came with it is relatively short. I wanted to mount the monitor in a group with the other meters/switches so I purchased this. If I had the tools to fabricate it, I would have made it. I could have cut the wire that came with it and spliced in additional wiring, but I did not want to do that.

When the vehicle is off, I'll need to test if V is supplied so as to not run down the battery.

Propane being so cheap and the system easy to manage, I think I'll be looking at that as the go-to for the fridge.  I do have a CPAP machine, so making sure I have solid 12V power for at least 6 hours every night is important to me...I've got a 200W solar suitcase setup, a small generator (if need be), and a DC-DC power supply for the CPAP which is much easier on the power usage (turning off humidifer etc), so should be OK.

I'll swap out all the lights in the R-Pod for LED...what else uses DC in these?