How To Charge Trolling Motor Batteries While On Lake?

I don’t have to tell you the importance of trolling motors for fishing. And, keeping the batteries fully charged during the season is similarly important. Lots of busy people wonder how to charge trolling motor batteries while on lake.

The answer is simple. You can charge trolling motor batteries using the outboard motor while moving. Or, use solar panels while the boat is not moving.

In this article, I am going to explain both methods along with proper installation processes. So, don’t skip any part if you want to get benefitted instead of creating more problems. Let’s get started.  

How to Charge Trolling Motor Batteries While on Lake?

From the introduction, you have already got the ideas for charging your trolling motor batteries.

Just like a car engine, you can connect the batteries in your boat in a way to charge while the outboard motor is running.

Now, you must be thinking about whether there is a way to charge the batteries while the boat is in an idle position.

Well, the solution is integrating a solar system. You can hook up the batteries to the solar panels and keep them charged all the time.

Below, I am going to describe the setup process and the necessary components for the installation.

1.     Charging While Moving

In the first method, you have to upgrade the outboard motor by installing a regulator/rectifier.

It charges a battery by converting the power of the motor to an AC/DC.

Step 1: No matter what the motor type is, you have to keep the basic diagram in mind. In the beginning, connect the green AC wires of the rectifier to the outboard motor.

Tip: It is possible to connect the green wires to the existing setup. Locate the cables under the flywheel, and join them. Here, ensure that you are placing the ground wire properly.

Step 2: After that, connect the red and black (DC connection) wires to the trolling motor battery.

Tip: Attaching crimp connectors to the red and black wires can secure the battery connection more than anything.

Alternate way: I am proposing another method for charging trolling motor batteries.

Here, you have to simply use a battery combiner to share power between the starter battery and trolling motor battery.

You know that the alternator already charges the starter battery. After installing the battery combiner, you can also recharge other batteries.

From the pictures of the product, you can see that there are 4 wires. For more information and a hands-on experience, watch this video.

Also, don’t forget to check out this diagram to get the basic idea. It shows you that there are no switches required for this setup to work.

2.   Charging While Sitting Idle

Here, I’m going to suggest a 20W 12V solar panel with the necessary mounting gear.

You can either research and find a suitable product or check out this one from Topsolar.

Step 1: Using the clips and other mounting components, install the panel in a suitable location on your boat.

Step 2: Connect the batteries directly to the panel using the wires and connectors. For larger distances, you can buy additional wires.

Step 3: Finally, face the panel 90° towards the sun for maximum efficiency.

How to Charge Trolling Motor Batteries to the Right Amount

Both overcharging and undercharging trolling motor batteries are possible, and they can cause some problems.

Overcharging leads to overheating and the acid inside the batteries start boiling. After a certain time, the casing gets broken resulting in spillage.

On the other hand, undercharging leads to a serious problem which shows its effects in the long term.

Here, sulfate crystals form on the negative terminal indicating the sulfating problem. It can decrease the life and efficiency of the battery.

The solution to both issues involves buying a smart battery charger. I can’t think of any other brands other than NOCO.

Their Genius GEN5X2 charger is the right option for marine applications. It can optimize charging according to the outdoor temperature increasing the batteries’ life.

Is It Safe to Charge Trolling Motor While on Lake Fishing?

Yes, it is completely safe and lots of boat owners are doing it. From the methods I have described above, nothing can go wrong.

I mean that there will be zero chances to damage the boat or other components.

In the worst-case scenario, the solar panel, regulator/rectifier, or battery combiner may go bad.

And, your trolling motor battery won’t get sufficient charging power. Before going on a fishing trip, check these electrical connections.


Those two are the best answers regarding how to charge trolling motor batteries while on lake.

If you know other tricks, please let share them with us. Keeping the batteries charged can prevent unwanted situations.

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