help with on board charger install

thanks in advance!!!…I bought a 12 amp charger from cabellas over the weekend…i went to look at the best way to install on a 2002 18ft explorer ss that i just bought and there is 2 12 volt batteries in a storage box right next to the console (see attached picture)…the 2 batteries are hooked up to a 55 pd autopilot that only needs a 12 volt…first question is if i’m running the trolling motor will the system go right to the 2nd battery when the first is low?…the only thing hooked up to these 2 batteries is the trolling motor..the starter battery is in the back where everything else is hooked up to it…I think that maybe i should install the charger underneath the console and drill a hole in the floor and then another into the dual battery storage box and feed it in…does this sound right?

The charger that i bought can be hooked up to 2 batteries…should i hook the charger to both batteries next to the console or can I hook only one cable here and will it charge both batteries?…than I can run the other cable to the starter battery…OR will the starter battery charge as i run the main moter, if so then i could hook up both cables to the 2 batteries next to the console…hopefully this is enough info…THanks for the help!!!!

pistolpete, what you have is the batteries are in parallel to supply 12 volts to the trolling motor, hook the on board charger to the batteries ( pos to the reds, neg to the blacks ) in order to include the starting battery you would have to get a 3 bank charger. Ron

PPete,
your main engine will charge up your starting batt at a sufficient rate. I’d put both the leads on your trolling batts. Jack..

thanks for the help!!!

jack I see you live in AV
I just purchased a 2 bank charger and a 24 volt minnkota, I am having some difficulties wiring it, could you drop me a PM and maybe work something out this week?