Charles B. Summers wrote:
In getting ready to replace my 12v trolling motor with a 24v, I've went
ahead and installed the second battery in the boat. So right now, I'm
wondering how to charge all three batteries with a two bank charger. I've
hooked the charger up to both trolling motor batteries, removing one set of
leads from the cranking battery. This is just temporary so I can make sure
that the second one is fully charged in case the other runs down.

Is it necessary to recharge the starting battery all the time like the
trolling battery? I'm know the motor will keep a charge on it, but is it
enough?

What if I connect the two trolling batteries parallel? How should I charge
them?

Am I going to need a three bank charger or add a second one for the starting
battery? I'm totally not familar with any of this...

Charles, since I have no boating experience, I'm probably not the best
to answer this, but lately whenever anyone has asked a battery question,
somebody (memory fails me) has posted this link. It has more information
than my little mind can wrap around, maybe you can find your answer here.
http://www.uuhome.de/william.darden/
From what I understand, (remember who's talking) you shouldn't have to
charge the starting battery unless you are storing the boat for a long
period. (2 months or more) If storing, you should charge every few weeks
to extend the battery life. It shortens the battery life if left low on
charge for any length of time.