I have a 24/70 MG that I am replacing with a 36/109 MG tour, and I was wandering how to connect the 3rd battery to the bank. I have 2 sets of wires coming from front. I understand how to do it with one set, but I guess I'm just lost with having 2 sets of cables. Thanks for he help

I understand that, but I have 2 separate cables labeled battery 1 and battery 2 coming from the plug in the front. So should I just hook them both up to the same battery and do that? Or is there another way I should wire it

I would double up the trolling cables batt 1 and batt 2(match colors)at the front and at the battery connections and connect as above at the batteries. Make sure you use large enough wire between the batteries.

I wouldn't hook up a battery to cables I don't know about. Most modern bass boats only have a single red and black cable from the battery compartment to the front of the boat. If the boat is a 1990's era boat it may be wired for a 12/24 trolling motor that required both 12 and 24 volts. This was would require a minimum of three cables. Another thought is if you are not the original owner of your boat the original owner may have had a cable failure and installed new cables so one set may be bad somewhere out of site in the boat. Sounds like you need to take apart your front deck console to determine what you have and do some continuity testing. But if you know which cables you used with the 24V, those should be the same ones you use with a 36V using SkeeterDon's wiring diagram above.

If the 2 cables are labeled "battery 1" and "battery 2" I doubt someone pulled another cable. You can get 12/24 v with 2 pairs of cables using the correct wiring in the correct plug. Doubling the wires gives him 1 pair like large "modern" TM's accept.

also make sure you have the right fuse as well.