24 volt wiring

I got permission to use this article from Mark, the guy that wrote the article about 24 volt wiring.  This is a basic how to wire a 24 volt trolling motor. I want to thank him for allowing me to repost it here. I hope it helps some of you out. He Goes by Gama on BillsBait.com forum………Enjoy!

This is a post that I wrote for Mr. Stratos when he was doing the original build on the crawdad he has posted for sale right now (sick deal can’t believe someone didn’t snatch it up yet). The example is a crawdad but the procedure and parts would be the same for any size rig. I stumbled upon this while looking thru the old computer for some pictures. Hope it helps – let me know if anyone has questions.

Wiring a 24 volt troller is basically the same as a 12 volt with a few minor twists. First you are going to need 2 batteries to create the 24 volts. You get 24 volts by wiring the batteries in series. This is done by jumping the negative post of one battery to the positive post of the second.

You will need two batteries that are the same size, age, and health. Its best to use the same brand as well, it makes balancing them easier. If they are not the same size or one battery is stronger (healthier) then the other you will not get the full performance from the system and your batteries will die sooner. Un-matched or un-balanced batteries will be constantly trying to balance the power between them. This means the weak battery will be robbing from the stronger one. This makes the stronger one work harder. The goal for ultimate performance and payback on your investment is to have 2 identical cells that are charged and discharged equally all the time. This is not easy to do but with the right set up and good habits it’s doable.

You will also need wiring. For the length of the run from the back of a crawdad to a 70 lb thrust bow troller you will need 6 gauge wire. Anything smaller will rob power and potentially cause the wiring to overheat and melt. A few different substitutes for marine wire were mentioned in the other thread. Marine wire would be best but you can cheat here because your wiring can easily be replaced down the road if there is problems. Marine wire generally has insulation that is made to deal with water, gas, and oil so it last longer. The insulation on household wire can not handle these things as well and will split and crack. Also marine wire is annealed (soft) making it easier to snake through a hull and go around bends. The other quality that marine wire has that standard household or regular stranded wire doesn’t have is the bonding. Stranded marine wire uses smaller diameter strands then regular wiring, this results in less voids and a tighter bond between the insulation and inner core strands. This helps prevent water from wicking in under the insulation. If water gets in it will eventually corrode the wire from the inside out. Stranded wire is like a sponge, it will actually suck water into the core so marine grade is better at preventing this. As a substitute to marine grade wire (6 ga. will be expensive) I would go to Wal-mart and get some 16-18’ jumper cables that are at least 6 gauge and use that for your wiring. This is sort of like the red / green show version of the right way to do it but your wiring will be exposed and easy to fix if need be. I did this in my own crawdad and cut the cost of the wire in half.

Next you will need terminals and connectors. Attaching terminals to large gauge wire with crimps will often result in a poor connection between the wire and the terminal. I usually solder the terminals on. I suggest using Anchor terminals as they are sold at most marine supply shops and they are good quality. Soldering them is easy. Brush out the end the wire goes into with a wire brush and then coat it with soldering flux. Next strip off the appropriate length of insulation from the wire. If the wire is not color coded or you use the jumper cables use a piece of red shrink tube to mark and protect the positive side and a piece of black shrink tube for the negative side.

Slip the shrink tube on before you solder the terminals in place because they won’t fit after the terminal is installed.



To attached the terminal to the wire, flux the exposed wire that you stripped. Then hold the terminal with a pair of pliers (on the ring end) and heat the cup up with a torch. Once it’s hot enough fill the cup with solder while keeping the torch on the cup so everything stays liquid. Also try to get the wire end that will be inserted into the cup near the flame so it get preheated. Don’t go to crazy with the heat. You only need enough to melt the solder. Once you have the wire and cup with solder all set, insert the wire (solder will come out so be careful) and hold them together until they cool a bit. While they are still hot wipe them off with a damp rag to clean the flux and make them shinny. Now slide the shrink tube in place and heat that to shrink it. This can be done for the ring terminals at the battery and for the butt connectors at the plug. I would suggest starting with the ring terminals for the battery connection and then waiting until you have the wire actually run to the front before cutting the length or attaching the butt connectors.

So now you have your 2 batteries and the wiring to run to the troller but there are still a few things you need on the battery end of things. You will also need a jumper cable to link the positive of battery one to the negative of battery two. Along with this you should add a fuse or breaker to protect the batteries in the case that there is a short in the circuit. Most people see this as over kill but its cheap insurance and batteries and your troller are more expensive to replace then the cost of the fuse or breaker. The breaker should be within a few inches of the positive battery terminal. What type of breaker you use will determine how the jumper is attached to it. So you may ultimately need two short jumpers instead of one long one. I have attached a picture of a cheap (5.00) auto reset breaker (its all I have right now).


They work fine but I don’t like to use them because they will often just reset and you won’t realize that that there is a problem. I like the push button reset style but they cost about 30.00. This requires that you push the button to close the breaker and then you know for sure that something is wrong. For the jumper cable itself you can buy a cheap battery cable form wal-mart and use that (see picture) or make one from the wire you will have left over from the main wiring.


The breaker between the batteries is over kill and can be skipped but I always add one. Next you will need another breaker for the main wiring. This one will go between the positive on battery one and the troller. This one is a must and should not be left out of the installed system. The wiring for it will basically be the same as the jumper set up. You will probably need a short pigtail for this. There are also breakers that can be attach directly to the battery terminal and then the wiring attaches to that. This eliminates some of the stuff you need to make up but there are only a few breakers on the market that have this set up.

So now at the battery end you have your two batteries with a jumper and breaker between them and your main wiring with a fuse of breaker on the positive wire. At this point you can run the wires to the front of the boat. In my crawdad I used some PVC tube clamps that they use for making green houses as a channel to run the wire through. These are about 4 feet long and look like half a tube. They are used to attach clear plastic to tube frames. You can get them from any green house supply place for a couple of bucks. I ran my wire up the left side top edge of my crawdad then covered the wire with these tubes. I used metal tube clamps and aluminum sheet metal screws to hold them in place. This keeps everything nice and neat and out of the way. This way I can flip the crawdad over and not have the wiring fall out. It also keeps the wiring out of the bottom of the boat while I am fishing.



At this point you should now either have fallen asleep, decided that this is not worth the effort, or have the batteries set up and wiring running to the front of the boat. If it’s the last thing mentioned continue on. If it’s either of the other two I apologize and you can do what ever you want.

Now you need to connect your feed wires to the trollers plug. You mentioned that your plug has 3 wires. That is for a different way of wiring and I will explain how to hook it up using just the two that are coming from the back of the boat. The 3 wires makes 24 volts at the plug instead of at the batteries but requires more wiring. This is sometimes done so that other things that are 12 volt can be attached to the batteries but it’s a bad practice and I don’t wire 24 volt systems this way. It creates the imbalance that I mentioned earlier. Using two wires and dedicating the batteries to the troller ensures best performance from the system. Now what you need to do is attach the 2 wires to 2 of the wires on the plug. If the plug wires are a smaller ga. that’s O.K. a very short length of smaller gauge wire won’t hurt. A long one will. You can either solder the butt connectors or use the crimp style. I use soldered ones. Do the same thing with the shrink tube as you did for the battery ring terminals. It doesn’t matter what two wires you connect to just make sure you use the same two for the troller leads and troller plug. The third wire can be cut off or left in place it doesn’t matter which you do because that wire has no juice and no function. After hooking up the receptacle to the wiring do the same thing for the plug and trollers wiring. Again make sure you use the same two corresponding wires at the plug that were used at the receptacle. Slip some shrink tube on before making the connections and make sure you have not crossed up the negative and positive feeds before making everything permanent.

Now you should be all set. You can skip the breakers but I never suggest doing that. The wire and other parts you use come down to budget and availability. I always try to take the path of doing it right and never looking back or worrying about it again but you can save some time and money by cutting some corners.

Here is the recap of what you need.


2 batteries

2 breakers (50 – 60 amp)

1 jumper cable ( maybe more depending on what breakers if any that you use)

6 ga wire

Ring terminals

Butt terminals

Troller plug and receptacle


– Mark



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