The above problem that the OP had is a good example of how much faster trouble-shooting would have went with a built-in ammeter for their RV's battery system.
An ammeter shunt in the battery bank's negative or positive main cable to the RV with the shunt's digital readout on a wall in the RV would have indicated that too much negative (-) current flow from the batteries was occuring ... showing that the problem was entirely due to either no charging taking place at all, or due to too little charging taking place.
We've had a built-in ammeter in our RV for years, and it's readings have helped save our bacon a few times when things went haywire in it's 12 volt system. It shows (+) readings when the batteries are overall receiving current and (-) readings when the batteries are overall delivering current.
