We just bought a 00 Caravelle Interceptor 212 and would like to add an extra battery to the boat. I've searched quite a bit for information on batteries and wiring, but am still a little confused. <br /><br />I have picked up a second battery (largest Deep Cycle that Sears had) already and just need to know how to wire it. I'm thinking all we'll do is add an isolator so that both batteries will charge off of the alternator, but wanted to make sure that is ok. We physically disconnect the batteries after we're done boating each time and if we were in a pinch and the starting batter was dead, we could always move batteries around, so I'm not too concerned with adding a switch. I also think I've seen enough info on how to wire the isolator that I'm not too confused with that. <br /><br />My main question I guess, is how does the second battery need to be ground? Can we just run a wire from the second battery to the first or does it need its own seperate ground? Or, does it need a ground at all? I know we need any accessories to be ground to the battery, but is that it?<br /><br />Any input would be appreciated.<br /><br />Thanks,<br /><br />Dan