Wiring a 12v TM battery

[RTZ]

I am installing a new TM battery and came across a strange setup. I know this should be easy but the current setup is abit confusing. I have 3 large wires going back to my current 12v battery. There are 2 red wires that are exactly the same (no yellow or orange or striped) that connect to the positive terminal on the battery and one large black wire going to the negative battery terminal. I have read there should only be 1 red and one black. So which red do I use? Does it matter? The plug recepticle at the bow has all 3 wires installed. One large red wire is connected to the top of the 3 prong recepticle. The black and other red is connected to the bottom of the recepticle across from eachother. I feel I need to disconnect and cap one of the red wires, but which one? Again just a 12 v TM and one battery hookup. Thank you for your help.

 

[ESGWheel]

It seems by your description that your boat is set up for a trolling motor which can take 3 wires per this link. (see the 12/24 V section) Can you confirm your TM is 12V and that is how you have been using its always (i.e., only one 12V battery which you are now replacing)? Does the plug attach to the TM have 3 prongs as well? I suspect that the previous owner simply wired up the 2 hot (red) wires to the + battery post to install a 12V TM or perhaps run the 24V TM at 12V. Regardless a guideline I go by sometimes is: if works that way before it will work that way again, i.e., replicate exactly what you have but with a new (same voltage) battery.

That said, I strongly suggest you pull the string on your current TM and boat set up and validate that all is as it should be. Example: get the install instructions for the make / model of your TM and determine if your boat has a 12V / 24V switch (as some do from what I have read). Perhaps even post your TM & boat’s make/model if need help.