Battery Gurus...I need advice.

[Mr. Pike]

I am replacing my current 12 volt 50# MK trolling motor with a 24 volt 65# Minn Kota US/Auto/Co Pilot. Will two Series 24 AGM batteries be enough for the new Minn Kota or would you recommend 27 series? Also, please keep in mind I have a weight concern. I am moving the current (2) batteries from the back to the front of an older Tracker Pro 17. I have a dual bank on-board charger. Can I charge the batteries that are connected in parallel from one bank and the starting battery from the other bank or should I charge both trolling batteries with both banks and forget about the starting battery?

 

[Silvertip]

Re: Battery Gurus...I need advice.

First -- If you have a 24V motor your batteries are not wired in parallel, they are wired in series. That means BAT #2 POS is wired to BAT #1 NEG. BAT #1 POS goes to motor POS. BAT #2 NEG goes to motor NEG. If you have a dual bank charger it MUST be 12/24V capable. Otherwise the batteries must be charged individually. 12/24 capable chargers must have isolated grounds so that the outputs can be bridged or connected in series just like the batteries. If your charger does not have that capability it can still be used but a switch needs to be installed to separate the batteries when charging and to separate one of the charger ground leads when not charging. As for batteries, buy the largest capacity (not physical size) you have space for. In other words don't buy based on group rating. Batteries from different manufacturers will have different capacities (A/Hr ratings) even though the group or physical size is the same.

 

[LubeDude]

Re: Battery Gurus...I need advice.

If you put two group 27s in the front of your boat, you are going to have handling problems, Maybe even two group 24s. There is a reason that they put them in the rear.

 

[Mr. Pike]

Re: Battery Gurus...I need advice.

Thanks folks. You are correct, "series" is the word I needed. My charger does 12 and 24. (Cabelas Pro 20). The two batteries in the back of the boat were aftermarket add - ons. I talked to Tracker today and described the location for the new batteries. Like you, I had the same concern about handling with the added weight. Tracker told me the location I chose should not impact the handling...much. I'm still skeptical. The batteries I am considering are Cabelas AGM in series 24. With regards to Capacity, is there a magic number I am looking for?