Need some battery advise/opinions....

[Idlewildman]

I am setting up a 1987 170, just finished new tank install and rewire. I have installed a 80# riptide 24V trolling motor. I'm not sure how to decide what battery I should connect accessories to. I plan to run 3 batteries (1 cranking and 2 deep cycle). Should I connect lights, bilge pump, stereo and electronics on to the deep cycles with the trolling motor or on the cranking battery with the outboard? Please let me know how your batteries are set up, any ideas/suggestions is appreciated.... Thanks 

[RickK]

I will have the same setup and plan to connect everything except trolling motor to the cranking battery.  I will use the trolling batteries to crank the engine in an emergency.

[Capt. Bob]

Let me ask this:

What is your intended usage on a regular outing?

Are you planning to recharge the two trolling batteries after each day on the trailer?

You do want the option of an emergency backup starting battery should you need it, correct?

Are you trying to wire the system so as to recharge all the batteries (not necessarily at once of course) while underway?

Size of outboard (90 HP Yamaha)?

I ask these things because it will make a difference in the actual wiring set up. As per Rick's idea, you may want to consider using a deep cycle battery as a combo for your starting. Modern deep cycle batteries have higher cranking amps and the extra capacity to power your accessories. That leads to having all three batteries the same type if that is something that appeals to you.

Good luck.

[Idlewildman]

Eventually I intend to install an onboard charger for all 3 batteries and recharge after each trip. In a emergency I thought I would just swap leads to a deep cycle if needed for an emergency start. Is there a way to charge while underway? If so would that take the place of an onboard charger? And yes its a 90 Yamaha.....

[RickK]

I will also have an onboard charger which I'll leave plugged in while the boat is at home. I don't need much accessory power (chart plotter and the radio) as I do mostly day fishing. I have a handheld vhf for this boat.  So most of my battery power will be used by the trolling motor, which will have it's own isolated battery bank.