I appreciate your advice on this issue back in April. I figured I'd post an update with what I actually did.
Firstly, I moved the wiring for the existing battery from under the entry step to under one of the dining seats. That's where the last owner had his separate battery and inverter. So now I have both new LifeLine batteries together in one space with the inverter.
I replaced the solar controller with a Renogy MPPT controller that understands the battery charging characteristics. The one i got is this one
. It may not be the best, but it's working great for me now.
Lastly, I replaced the inverter with a 3000-watt unit. It's the 3000-watt version of this one
. I know it's overkill. I don't plan to use 3000 watts, but it does have the ability to wire outlets into the house system. I plan to switch over one or two of the house outlets to connect to the inverter instead.
The whole system is working great! We parked in the shade of redwood trees for 3 days of camping with friends and had plenty of power to make a pot of coffee each morning and use what lights we needed plus a fan (it was pretty warm). Once we got into the sun, it charged up again quickly.
I tried plugging the fridge (2-way, 120v & propane) to see if it was a good idea to run from 120v on the inverter instead of propane. Looks like that might be a fine option if I'm parked in the sun all day, but overnight it'll drain the batteries too much. Better to just run it on propane as that seems to work pretty efficiently that way.
Thanks again for all your advice!