On Wed, 13 May 2009 21:24:13 -0700 (PDT), Tim
wrote:

My question is this. Why do you feel you need a battery charger on the
boat? If the charging system is good and there is no electrical draw
(leakage) your boat battery should stay up for the whole summer.

That's fine for engine starting batteries that never get discharged to
any real depth and are otherwise in good condition. "House"
batteries and trolling motor batteries rarely see enough run time on
the boat to be completely recharged however. Fully recharging them at
home or dockside will greatly extend their life as long as they don't
get over charged in the process.