Jim, you know you're going to add more solar, so who ya tryin to kid?
I have the FlexMax 80, and while I often call it a "boat anchor", that's only because it's the size, shape and weight of a giant boat anchor. It is also the most powerful and flexible unit out there, still.
While my own needs for solar have done a complete 180 away from the hard, semi-residential RV install, I still can't get away from the FlexMax, it is the ONLY charger (AFAIK) that will do everything I want. For this reason I'm actually considering unbolting it from the TT and lugging it with me for tenting, although the truck would certainly ride low on whichever side I'd stowed it.
Purely because of the size and weight, I'm actually considering the Renogy 40a MPPT, which is not even half as capable. However, it is about a quarter of the size and weight, and I could easily pack two if I ever got that many panels.
I know there are some True Believers here in future solar innovation, but to my eye the pace seems glacially slow. My advice is to pick one of the options out there now that allows for future expansion, and then let innovation arrive at its accustomed pace.
