Why bother,i would start from scratch using a new led fuse block ans sep wires to each unit,ie ,lights toilet ,tv,and any heaters etc.
use a up to date charger and a mains switch over in case you find a site with x wiring.
If solar is on roof then a mppt unit as in pics as this will also charge hab and starter batts.
More simple to fault find and replace one unit if it goes down rather than it all in one sys.