Add a Parallel Battery for Trolling Motor

[JIMMYTHEFISH]

Hey guys, Love the website. Right now I have one battery powering my 12,V T.M. I want more run time so I want to add a 2nd Battery in the bow. I understand wiring in parallel should keep me at 12 V. Im unsure how to connect the second battery. Ive heard not to put more than one wire on a battey post, batteries must be same size and age and wires must all be the sme length... Any truth to these? Also can I charge both batteries at the same time? Or should I disconnect all the wires befor charging them one at a time. Im looking for something simple that I wont have to fuss with on or off the water.

Thanks, hope to hear back

 

[fish devil]

:twisted: Connect positive to positive, negative to negative. I have three batteries on my 16' Tracker. Two of the 31 series are connected in parallel for my 12v bow motor. Been doing this for 12 years. It's better to have equal size and age batteries. Both get charged at the same time.

 

[JIMMYTHEFISH]

Thanks Devil, sounds easy enough. So my trolling motor can still attach to my battery at the back of the boat, as long as I correctly run wires to the battery in the front? And when I put the charger on either of the batteries it will charge both assuming the batteries are wired together? Thanks man,

 

[Bugpac]

Get a battery selector switch, then if you have a battery loose a cell or something it don't ruin the other battery.

 

[russ010]

Thanks Devil, sounds easy enough. So my trolling motor can still attach to my battery at the back of the boat, as long as I correctly run wires to the battery in the front? And when I put the charger on either of the batteries it will charge both assuming the batteries are wired together? Thanks man,

It will charge both batteries connected in parallel - but it will take longer. If you can unhook them from each other, then put a charger on each battery independently to charge - if one battery is dead or getting weak, you'll find out sooner rather than later. When you have the batteries in parallel, each battery will act as a charger to the other battery. If one battery is old, and one newer, the old battery will probably drain faster, which in turn the "new" battery will compensate it's amp to charge the other battery up to the same level.

General rule of thumb is to have 2 identical batteries if possible... that way, they should both hold the same float charge and dissipate amp at the same rate so that one doesn't rob from the other when you're not on the trolling motor