ok so im a little embarrased i have to ask this after all the years and boats ive owned but here it go's. i just bought a new to me boat it is all set up for a 24 as it came with an 80 terrova. i got a stupid deal on a 112 foretrex and sold the terrova. here is the question. i have all 3 batteries i need. but the boat is wired so that there is a positive and negative going to each battery. how do i wire in the third battery....