Depth Finder Wiring

I have a 24 volt trolling motor on my boat and I want to add a depth finder to my trolling motor. It says the depth finder should be wired to a 12 volt battery. Both of my trolling motor batteries are located in the front of my boat. It is a 1850 c-liner sportfish. My question is would it be o.k. to wire the depth finder to just one of these batteries??? I am confused because I would think it would be drawing from 24 volts and not 12, but I was told if I wire it just to one battery it would only be drawing from one 12 volt battery. Just wondering if I was told right or not. Thanks!!

Right,

As long as you hook the depth finder to only one battery, meaning the positive and the negative terminals of the SAME battery it will only be 12 volts, I have some stuff rigged like that in my boat and it works just great!

Brad Guck

However you may receive interference from the trolling motor when hooking it up to the trolling motor battery. Manufacturers recommend hooking it up to another battery. In some cases it won’t matter. Just a heads up though

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As long as you hook the depth finder to only one battery, meaning the positive and the negative terminals of the SAME battery it will only be 12 volts, I have some stuff rigged like that in my boat and it works just great!

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Same here. I run my sonar off one of my trolling batteries and have no problems. Hook it up and try it. If you do get interference, you can always change it to run off your cranking battery.

Thanks for the input guys. I am going to work on it tonight. It sounded logical but I just wanted to make sure before I started sending smoke signals out the garage door.

I originally had my front LCD connected to the trolling motor batteries. It would read bottom at all times, but when the trolling motor was running interference would appear or fish disappear. As soon as the trolling motor was off, the interference would disappear or fish immediately reappear.

Last spring before season, I rewired it to use the starting motor battery. It was not easy running the wires, but now there’s no interference at all.

I’ll agree that you have a big potential to get interference from the T-motor. I’d suggest splicing into another 12 volt source at the bow. I wired mine into the power supply for the tilt/trim switch. You could also use you wires from the bow lights/courtesy lights, just may need to flip a switch to run the sonar.

-J.

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I’ll agree that you have a big potential to get interference from the T-motor. I’d suggest splicing into another 12 volt source at the bow. I wired mine into the power supply for the tilt/trim switch. You could also use you wires from the bow lights/courtesy lights, just may need to flip a switch to run the sonar.

-J.

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If you do that, make sure you wire to the “Hot” wire and not the “Load” wire. If you mix them up, you will make your tilt engage when you turn on your graph. The lights run off a swith at the bow, and is not hot at the bow until the light switch is turned on. Therefore your lights would have to be on when you want to use your graph.

Otherwise, if it is a console boat you can run it to your “Master Power” which is what I strongly recommend. That way when you power off your main power, your graphs go off and not draining the battery by being accidently left on.

Well I worked on it last night and got it halfway figured out I think. We did blow a fuse so we had to stop, didn’t have any extras on hand, but I will tonight. We added a couple things to it like a plug in and a switch so that is why I think I blew a fuse. We are getting close just need more fuses and Thanks for the input guys. Then I need to hit the river to make sure about the interference potential.