Adding another battery

[southtexasbassin]

I am fixing to add another battery to my boat.  I want to replace a 54# Motorguide trolling motor with a 70# Minn Kota.  The problem I am having is that my boat has a 12v battery to run the current trolling motor.  So, I have to add another battery to be able to run the Minn Kota(24v). Can you all give me some advice as to what I am getting myself into.  Is it going to be very expensive?  Do I have to rewire the whole boat?  Do I need a different fuse box?  Will it affect any other electronics on my boat?  What is it that I am going to need to get this done?  Can it be done at home or should I buy the materials and have the boat dealer do it for me?  Any websites that may have useful information would be great.  Thanks in advance for your help.

[CHEVYRIDAZ]

All you will need is a new deep cycle battery,  4 gauge jumper cable and a 60 amp inline fuse. Connect the + lead from the TM to the + lead on battery 1. Than connect the - lead from the TM to the - lead on battery 2. Than use a piece of 4 gauge wire and terminals to jump the two batteries(Connect the remaining + and - terminals from the 2 batteries with this).

[southtexasbassin]

My boat has a that wall socket look alike to connect the trolling motor.  So the trolling motor doesn't connect to the batteries directly.  It just plugs into the socket.

[Choke Canyon Boy]

THAT WAS AN AWSOME ANSWER RIGHT THERE JUST SAYING.

[Jig Man]

If your existing trolling motor battery is more than a few months old you will need to get 2 new batteries as your system is only as good as your weakest battery.  Be sure to look for reserve amps.  180 or more is a must for all day use.

[southtexasbassin]

Great Pic.   Now I have a better understanding how the wiring works.  Im going to need a 60A inline fuse.  Is that correct?  I took a look at my neighbors boat yesterday and he has what he calls a breaker installed instead instead of a fuse.  Would you have any clue of whats going on there?  Or is the breaker acting like the fuse?

[Wayne P.]

Both serve the same purpose.

Most use a circuit breaker as it can be re-used after it opens (resettable).

A fuse will work, but has to be replaced if it opens. Also with a fuse, you have more contact points for corrosion.

[southtexasbassin]

Great information.  I currently have a 50A fuse for the 12v.  Will this fuse do for the 24v?  Or should I just go with the 60A?  How do I find out what size fuse to use or what size of breaker to use?  Thanks in advance for all the great information you all are giving me. 

[K_Mac]

Great information. I currently have a 50A fuse for the 12v. Will this fuse do for the 24v? Or should I just go with the 60A? How do I find out what size fuse to use or what size of breaker to use? Thanks in advance for all the great information you all are giving me.

Your motor manual will give you the size breaker needed (60A I bet)and the full load amperage for your unit. Most recommend 6 gauge wire also. If you are running from the back of the boat to the front and you do not have #6 wire, you may want replace the wire. #8 would work for a short run.