Typically, the on board charger on boats of the 90s were mounted on the inside back transom wall, centered. Would have had a Lester on board charger as standard equipment. Some people are building a bracket over the bilge area for mounting.If it were me, I would just get a portable charger and not worry about an on board charger now. Gonna be less weight back there on a 96 PII…and that boat at that age isnt going to lose weight anytime soon.I added a MK 330 charger to the 96 Eyra that I bought used 3 yrs ago. In retrospect, if I had thought things out, I would have just left it empty.96 Eyra/12 Mercury 175 Pro XS with 2015 single axle trailer2017 Victory Gunner