Dear, Rod
I am not sure how much money you want to put into boat,using the resources you have and the safety issues involved. I might be able to figure out a solution for you.
I would advise purchasing the highest ml amp/hr rated deep cycle battery you can find. I am not sure what brand is the best.
You will have 3 chart plotters, 2 fishfinders, 1 sub troll , 1 vhf , 1 am/fm and 3 riggers.
I would connect two batteries in parallel to run your elec. equipment. I would also recommend dedicating one marine cranking battery for your engine.
Do you have an inboard or outboard on your boat?
Do use a trolling motor?
Does your main engine provide enough charging power at low rpms to
to keep your starting battery fully charged?
There are a few ways to do this. Happy to HELP.
Send me a message letting me know,what we are working on.
Sincerely,
Jay