Hello , it's been a while I usually post in the class a forum , but now I got me another tc. Still got my executive however , reason for going with another tc , I am into gold prospecting here in Nm. ...
No on the solar thing (I don't do solar at all) but your porta-potti... If you are revamping the camper, why not install a Thetford Cassette toilet. No black tank needed, fully self contained and you can dump the integral black tank anywhere, residential toilet, pit toilet, outhouse or dig a hole in the ground and bury the effulent.
I think you have the wrong battery as well and I don't have or want solar. I run 2 6 volt Trojans myself