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12/24 Motorguide wiring help.

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  • 12/24 Motorguide wiring help.

    I have a 12/24 foot control trolling motor, Motroguide Brute 750 and am needing some wiring help. I am replacing a 24 V hand control motor. Here is my current set -up:

    The postive and negative for both batteries one and two run to the front of my boat.

    I have a three plug connector. Next to it is a switch that has a position for 12 V charge, 12V and 12/24.

    The plug is connected to a box that allows you to adjust the motor speed.

    What is strange to me is that only two wires go to this box. Both are 12 V. I thought you would need a ground wire going to this box also. (I assume I dont need this box anymore, because the variable speed is in the foot control).

    I would like to set the new motor to run 12/24. But the switch next to the plug has me all confused.

    Do I even need the switch?

    Should I jumper the battery back in the battery box. Or does this switch do that for me?

    Also, on the back of the 3 plug receptacle, where do I connect the red and black wires. There is a spot to connect on both sides of the plug and there is one spot that says ground.
    Do I hook the 12V on one side and then the 24 on the other and connect the common ground to the ground?

    Any help would be appeciated.



  • #2
    Re: 12/24 Motorguide wiring help.

    Here is a picture of the wiring for your trolling motor....

    You could remove the switch and then just have the wiring directed to the appropriate plug you need to get you back on the water.


    • #3
      Re: 12/24 Motorguide wiring help.


      Is there any problem with making the jumper connection at the front of the boat instead of back in the battery box? Just wondering because since all four of my battery cables are up front, I was thinking I could just connect battery one positive to battery two negative. Then connect the common ground to the plug and use just the 24 volt. I think I'll just not use the switch.




      • #4
        Re: 12/24 Motorguide wiring help.

        That should be fine...what is your fuel tank situation like? Do you have portable fuel or a built in tank. Where is your tank (if you have one) located. Just make sure you don't have any sparks coming from the connection that could ignite the fuel fumes....that's all.

        Good luck.


        • #5
          Re: 12/24 Motorguide wiring help.

          What the wiring looks like depends on what functionality you want. If you want the option of using either 12V OR 24V operation, then the schematic shown above will not work -- its a 24V only setup. Since you have a 12/24V selector switch on the trolling motor, you can use this schematic and eliminate one of the ground wires, and you can also eliminate the switch panel. The motor also has a speed control on the foot pedal so you can eliminate the speed control box on the boat. With this system however, you will need to charge each battery individually (at the battery) or install a dual bank on-board charger.

          The reason two sets of wires (one pair from each battery) were routed to the panel was for 12/24 switching and to enable charging both batteries with a single 12V charger through the receptacle. All that switching with more modern motors is not necessary.


          • #6
            Re: 12/24 Motorguide wiring help.

            Thanks for all of your help!! I got it hooked up and working. I went with the 24 volt only for now. Never have needed to go to 12V.

            I do have a 2 bank charger and it is connected to each individual battery. Is that the correct way to hook up chargers when you have the batteries jumpered?

            Thanks again,



            • #7
              Re: 12/24 Motorguide wiring help.

              Hey Silvertip,

              Another great schematic drawing. Wow, you really know your drawings, It seems like an art, and your the Master! LOL! Nice work! d


              • #8
                Re: 12/24 Motorguide wiring help.

                The two bank charger is just fine provided the outputs are isolated (no common ground). Most newer chargers have isolated outputs.


                • #9
                  Re: 12/24 Motorguide wiring help.

                  Hi Silvertip, great drawings but i have a 4 wire system coming from front of boat to batteries, they come from the charge/run switch and ammeter and trolling motor cord. Will you please put up a drawing of the 4 wire system??? Thanks (the colors are blue, white, red and black)


                  • #10
                    Re: 12/24 Motorguide wiring help.

                    Wes -- There are many different 12/24 as well as 24V wiring schemes so I have no idea how your switch panel is wired. There are several pieces to consider in a system like yours. 1) Wiring at the battery to the front of the boat. No problem there as we have four wires. Red (+) and Black (-) connect to one battery. Blue (+) and White (-) connect to the other battery. 2) Where the wires connect on the switch panel, how the switch is wired, where the ammeter is in the circuit, and what the configuration of the receptacle is what I have no way of knowing. 3) Do you have a 12/24 switch on the trolling motor? 4) how many wires are there in the trolling motor cable. 5) Do you use 24V only or do you use both 12V and 24V modes. If you are having a problem, post what the problem is and I can probably get you on the right track. I'll also look at my schematics and see if I have one that may be close. I know I don't have one with an ammeter in it but I can tell you where it would go.


                    • #11
                      Re: 12/24 Motorguide wiring help.

                      OK Sir, I understand this is a complex question thx for reply, since talking to u i have it wired up and now the only problem i have is when 12/24 switch (on trolling motor) is set to 12 i have 24 volt and vise versa. I think i just need to change positve wires at battery? By the way do u get paid for this? Well you should great info and i must say GREAT patience, thank you for help!!!!


                      • #12
                        Re: 12/24 Motorguide wiring help.

                        Switching the wires between batteries should solve the problem. As for being paid -- I get paid in the form of the satisfaction that comes with knowing I helped someone solve a problem. I'm retired and have a little time to help out. Why not do something constructive rather than sitting around waiting for the grim reaper. 8).


                        • #13
                          Re: 12/24 Motorguide wiring help.

                          I notice your diagrams have fuse on each pos wire .. what size and type should I use on my motorguide brute 56lb.
                          Thanx in advance


                          • #14
                            Re: 12/24 Motorguide wiring help.

                            50A if using 6 ga wire, 40A if using 8 gauge. I prefer breakers over fuses but fuses will work.


                            • #15
                              Re: 12/24 Motorguide wiring help.

                              My boat already rigged for 12 or 24 and had breakers already installed , thank goodness!

                              But the issue I had was on the marinco plug from 1986, it has place for three wires, white, black, green.

                              My motorguide trolling motor is white, black , red.

                              Standard industrial plc wiring, white is neutral , black positive, and green earth ground.

                              In your diagram black red yellow, when I do black-black / white-green / red-white 24 volt and 12volt was switched .. 24 was slow, and 12 was high.
                              I reversed them .. and prob solved white-white / black-black / red - green ..

                              I guess back in 1986 it was different .. my new to me 56lb thrust 12/24 is a 1996 model so 10 yrs apparently made a big difference in wiring code

                              Just a heads up to anyone else that runs into this prob.