Quote Originally Posted by Jman5626 View Post
It doesn't. It gets it charged then maintains. I just figure I'd leave it plugged in as long as possible so it doesn't drop back down any
It shouldn't drop that much charge in a weeks time (unless they're old & getting weak). So, what I would do is charge up one, then the other (all in one day if possible) ... then put the charger on each one every other day (or at least once, shortly before you intend to use it).

If you do decide to buy another charger, I'd suggest a onboard digital 2bank charger with 10amps/bank. Something like a MK220D, if it will fit in your boat. (and, yes I do know that they cost around $200 , I was just using that as an example )