Learning, Wiring,

What Gauge Wire for Trolling Motor? (Expert Advice)

Today you’ll learn what gauge wire is most suitable for your trolling motor if you plan to extend the wiring.

The size of the trolling motor wire can mainly depend on two factors. It depends on the amperage of the trolling motor and the length of the wire. In this article, I’ll explain this issue in more detail.

In general, if you extend the trolling motor wiring only up to 94 inches, you’ll have to use a 10 AWG 105C wire. However, if the length is more than 94 inches, you’ll have to use an 8 AWG 105C wire.

I’ll go into more detail in the below article.

How to Pick the Most Suitable Wire Size for Your Trolling Motor?

As mentioned earlier, the main two things that affect the trolling motor wire size are the motor’s amperage and the length of the wire. Here is a simple chart that can solve all your problems when it comes to trolling motor wire size.

Amp DrawAmp Circuit Breaker5 feet10 feet15 feet20 feet
12V3050A10 AWG10 AWG8 AWG6 AWG
12V4250A10 AWG8 AWG6 AWG4 AWG
24V5060A8 AWG6 AWG4 AWG4 AWG
24V4250A10 AWG10 AWG8 AWG8 AWG

However, understanding the above chart can be a little tricky. So, here is a step-by-step guide for finding the perfect wire size for your trolling motor.

Step 1 – Find the Amp Draw of the Trolling Motor

First and foremost, examine your trolling motor and find out its amperage. Most often, the manufacturers print the max amp draw on the trolling motor.

multimeter reading at 15.10 ohms
Video | monzsterman

However, if you have a hard time finding the amp draw, you can always get in touch with your merchant or manufacturer. Or use a digital multimeter to find the max amp draw of your trolling motor.

Here are a few simple steps for using a digital multimeter.

  1. Set the multimeter to amp settings. (select the appropriate range, typically 10A or 20A.)
  2. Start the trolling motor.
  3. Connect the multimeters, positive and negative leads, to the trolling motor.
  4. Note down the reading on the multimeter. (The reading on the multimeter will indicate the amp draw of the trolling motor. This is the amount of current the motor draws from the battery.)

Tip: Run the trolling motor at a maximum level while you measure the max amp draw.

How Can the Max Amp Draw Affect the Wire Size?

You probably heard about many different wire gauges such as 6 AWG, 8 AWG, 10 AWG, etc. These wires are categorized according to their thickness. For instance, the 6 AWG wire is thicker than the 8 AWG wire. And the 8 AWG wire is thicker than the 10 AWG wire.

When a wire has a higher thickness, that wire can handle more current. So, the 6 AWG wire is capable of handling more current than the 8 AWG wire.

That means with a higher amp draw, you’ll need much thicker wire for your trolling motor.

Step 2 – Measure the Length of the Wire

Then, take some measuring tape and measure the distance between the battery and the trolling motor. This will give you the length of the wire.

How Can the Length of the Wire Affect the Wire Gauge?

When the length of the wire increases, the voltage drop increases accordingly. Higher voltage drops can affect the amperage. So, you’ll have to consider the length of the wire before choosing a suitable wire gauge for your trolling motor.

For a better understanding, follow the below formula.

R = pl/a

Here,

R – Resistance

p – Resistivity (constant)

l – Length of the wire

a – Diameter of the wire

As you can see from the above formula, when the wire’s length increases, that wire’s resistance increases automatically.

Higher resistance leads to higher voltage drops. So, to counter this, you’ll need a wire with a higher thickness. That is why at 20 feet mark you should use wires with higher thicknesses such as 4 AWG and 6 AWG.


What Can Happen If You Use the Wrong Gauge Wire for Trolling Motor?

Well, using the wrong gauge wire can lead to many risky issues. Here are the two main risks that you should be careful of.

Might Start an Electrical Fire

Using the wrong size wire can heat the electrical wires and circuits unnecessarily. This heating can start an electrical fire. If you ever had dealt with an electrical fire, you probably know how hard to put it out.

On the other hand, it could damage your property, and in a worst-case scenario, it can inflict fatal damage on someone.

It Could Damage the Trolling Motor

This second risk is a bit less disastrous compared to the first one. But it can end up bad. Using the wrong wire gauge can damage the blow circuit breaker of the trolling motor. And replacing or repairing the motor might cost you a considerable amount of money. So, make sure to use the correct gauge wire according to the above chart.



Video References

Trolling Motor Parts

Team Reelin The Blues

monzsterman

Peter Ranieri II

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About Sam Orlovsky

AvatarCertifications: B.E.E.
Education: University Of Denver - Electric Engineering
Lives In: Denver Colorado

Electrical engineering is my passion, and I’ve been in the industry for over 20 years. This gives me a unique ability to give you expert home improvement and DIY recommendations. I’m not only an electrician, but I also like machinery and anything to do with carpentry. One of my career paths started as a general handyman, so I also have a lot of experience with home improvement I love to share.

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