Originally Posted by
EarmarkMarine
With a battery that has a 105 amp/hour capacity you need a minimum of 10 amps of charging capacity for that battery alone. With a standard 50 to 60 amp/hour starting battery you have exceeded the capacity of a 12 amp charger. Given that your boat will usually be put into storage with a nearly charged starting battery you could use a 12 amp charger. A 20 amp dual bank charger is a better fit however. In order to have the right amount of current to chemically excite your battery in order to properly desulphate you want a charger that is rated at between 10 to 13 percent of your total amp/hour capacity.
Also, if you are maintaining a flooded starting battery make sure that you have settings that are separate for the two banks. An AGM would like to see a little higher voltage for a little longer duration at the end of the charging cycle.
David
Earmark Marine