While the romance of the rod and reel will never fade, modern technology has changed the face of fishing. Fish finders and trolling motors have become invaluable tools in the angler’s arsenal, helping to locate fish, navigate waters, and maintain optimal fishing speeds. Connecting these two devices, however, can sometimes feel like a riddle wrapped in a mystery.

Don’t fret! This guide on how to connect a fish finder to a trolling motor battery will untangle the knots and get you ready for your next big catch.

Fish Finders and Trolling Motors: A Dynamic Duo

The Functionality of Fish Finders

The fish finder, as the name suggests, helps anglers locate fish in the surrounding waters. Using sonar technology, it sends sound waves down into the water that bounce back when they hit an object, like a fish or the lake bed. The returned signals are then processed and displayed on a screen, providing real-time information on what lies beneath the surface.

The Power of Trolling Motors

A trolling motor is a self-contained propulsion system with an electric motor and controls. It’s mounted on a boat’s stern or bow and provides a secondary mode of maneuverability. Trolling motors are particularly useful for maintaining slow speeds for fishing and for navigating narrow or cluttered waters where a boat’s primary motor may be too powerful.

The Connection Conundrum

The Challenge

Connecting a fish finder to a trolling motor battery may sound like a complex task. This is mainly because these devices are usually connected to separate power sources to prevent interference. However, with the right tools and a little patience, you can have your fish finder and trolling motor running in harmony.

The Solution: An Inline Fuse

The key to safely connecting your fish finder to your trolling motor battery is an inline fuse. An inline fuse is a protective device in an electrical circuit that shuts off the circuit when current flow exceeds a safe level. This can prevent potential damage to your fish finder from power surges.

Steps to Connect Your Fish Finder to Your Trolling Motor Battery

Step 1: Gather Your Materials

You’ll need a few essential tools to get started:

  • A wire stripper/cutter
  • A 3-amp inline fuse
  • A heat shrink tube
  • Electrical tape
  • A red power wire
  • A black ground wire

Step 2: Preparing the Wires

Use your wire stripper to strip about ½ inch of insulation from both ends of your red power wire and black ground wire. These will be used to connect your fish finder to the trolling motor battery.

Step 3: Connecting the Fuse

Attach one end of your red power wire to one end of the inline fuse. You can twist the wires together and then secure them with electrical tape.

Step 4: Insulating the Connection

To further secure and protect the connection, you can slip a heat shrink tube over it and apply heat until it shrinks tightly around the joint.

Step 5: Connecting to the Battery

Now, connect the free end of the red power wire (with the inline fuse attached) to the positive (+) terminal of your trolling motor battery. Connect one end of the black ground wire to the negative (-) terminal of the battery.

Step 6: Connecting to the Fish Finder

Finally, connect the other ends of the red power and black ground wires to the corresponding power supply inputs on your fish finder.

FAQ’s on Connecting FishFinder to Trolling Motor Battery

What is an inline fuse?

An inline fuse is a protective device used in electrical circuits that disconnects the circuit if the current flow exceeds a safe level, preventing damage to the connected devices.

Can I connect my fish finder to the same battery as my trolling motor?

Yes, it is possible to connect your fish finder to the same battery as your trolling motor, but it’s crucial to use an inline fuse to protect your fish finder from potential power surges.

What tools do I need to connect my fish finder to a trolling motor battery?

You’ll need a wire stripper/cutter, a 3-amp inline fuse, a heat shrink tube, electrical tape, and red power and black ground wires.

Can connecting my fish finder to my trolling motor battery cause interference?

While it’s possible for electrical interference to occur, using separate power sources for these devices can often mitigate such issues.

What does a fish finder do?

A fish finder helps anglers locate fish in the surrounding waters. It uses sonar technology to send sound waves into the water and displays the returned signals on a screen.


While the task of connecting a fish finder to a trolling motor battery might seem daunting, it’s a lot simpler than you’d think. With the right tools, a little patience, and the steps outlined above, you can set up a seamless fishing system that helps you navigate waters, locate fish, and enjoy your fishing trips to the fullest.

Anthoni Ja
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