Mysterious Electrical Issues

Going back to the beginning of your post, I believe you said that this was a new unit, purchased within the past few months. I'd haul it back to the dealer and let them solve it. 

A clamp-on ammeter that you can get will do that for you. You need to get one that will test both AC and DC amperes. I have a Southwire AC/DC one that works well for me. Here is one similar to mine which I purchased at Home Depot.

I appreciate all the brainstorming. Still not resolved - We have a drip charger connected directly to the battery at night now, which is keeping it charged enough to keep things running if I’m not working late in there. If I’m working and have all the lights on (and the speakers for music), I drain the battery by about 2am.

It seems like the only thing left it could be is a bad battery. I took the battery to autozone once to test but the charge level was too low for their tester to work.

We’ve double checked the brake cable. We’re definitely not running the electrical outlets off the inverter. Still plugged into shore power. Tested the output from the converter and it was fine. No blown fuses, no tripped breakers. During the day the button on the sensor panel inside will say the battery is 3/4 charged.

But before we buy another battery, I am wondering… is there any way to test the actual load being pulled from the battery? Not what the battery is capable of, but what is actually being used? Just thinking through this, either there’s a problem with the battery getting power to charge, storing power to be used later, or provding more power than it can handle. I feel like we’ve run through the tests on the battery getting power and that’s fine. We haven’t been able to effectively test it storing power, but my assumption right now is that this is the problem. But I would love to test whether the power the battery is unreasonable. Googling isn’t working (or my search terms are wrong) because all I’m getting is how to test the voltage the battery can provide - not what it IS providing.

I believe you still need 12V to run the control panel under propane though.

Li batteries are cost effective now if you do a lot of boondocking. Many upscale expedition style RVs come with them now. The cost issue is not the batteries as much as it is the charging circuitry. That can be an expensive proposition if you need to convert it, as we have to do with rpods. Also pretty involved for an inexperienced owner.

As for solar charge controller drain, that is generally very small or zero, most are set up so their electronics are powered from the solar side not the battery side. If there's no solar energy available they don't need to work after all.

But I do agree that disconnectinv the battery is a good idea, as long as you remember that you can't leave lead acid batteries disconnected for long periods. They will self discharge just sitting there, so you need to put them on charge at intervals ranging from a few weeks to a few months depending on the battery and the temperature (high temps more often than cold , deep cycle batts more often than auto batteries).

In this case though it sounds like the battery is going down even though the rpod charger is running which suggests that there might be a big load on somewhere, not just a small parasitic draw.