Made a huge amateur mistake last weekend... When reconnecting batteries last weekend I accidently reversed polarity on one of them and then turned the switch on. Needless to say wasn't pretty. The terminals on the both batteries even the one hooked up correct melted. The breaker on the battery switch did not trip. I took both batteries off and bought new ones. Only had one in stock so I only hooked that one up today after replacing the lugs since they soldered to the old battery. All breakers on the panel were off and all components appear to be okay with some interesting exceptions... I only have one batt hooked up now, the number two. When I select two or all on the batt switch everything works except the stereo which only works with selector on all despite having only one batt on the boat. How much damage have I likely done? Do I only need a new switch? What about starting system? It's on hard so I didn't try and start it but I do get low oil press light and alarm with ignition on.