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How To Charge A Trolling Motor Battery

Mark Armstrong
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If you’re heading out for a day of fishing with a trolling motor it’s a good idea to know how to charge a trolling motor battery or you could end up with a dead battery halfway through your trip.


But worry not! To make it a little easier, we’ve put together this short guide with tips on how to use different types of chargers.

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Trolling Motor Battery Types

Deep Cycle Battery

A deep cycle battery can be the best choice for a trolling motor as this type of battery is designed to be charged and discharged frequently. Within this deep cycle category there are different types, including AGM (Absorbed Glass Mat), wet cell and gel.

AGM and gel batteries are both completely sealed. A wet cell battery is not sealed and can require ongoing maintenance to prevent corrosion. AGM batteries can be the better choice when it comes to trolling motor batteries as they can be more impact resistant and can be quicker to charge.

Types Of Chargers

There are probably three main types of chargers that can be useful for charging trolling motor batteries. These are solar chargers, on-board chargers and portable chargers.

On-board chargers usually need to be permanently installed onto your vessel. Some solar chargers may require installation too, but portable chargers can be more convenient for smaller boats and kayaks where you may not have the space to install a charger.

Solar chargers use the energy from the sun to deliver power to your battery. On-board and portable chargers will usually need to be plugged into an electrical outlet in order to transmit power and charge your battery.

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What You Need To Start Charging?

  • Deep cycle battery
  • Battery Charger – ideally one that has as many banks as you have batteries in your trolling motor system
  • Power outlet – this could be an extension cord or, if your charger cable is long enough, a wall power socket.

How To Charge Different Types Of Trolling Motor Deep Cycle Batteries

The type of charger you use will usually depend on the type and number of batteries you have. Chargers with multiple banks can be more suitable if you use more than one battery as it can charge two or more batteries at the same time.

On-Board Chargers

Step 1: Unplug Your Trolling Motor

Firstly, it can be a good idea to unplug your trolling motor from the battery, as well as any other electronics that are connected to the battery. You may also want to make sure that the battery is clean and dry.

Step 2: Connect Your Charger

Connect the leads from your charger to your battery, attaching the red positive lead to the positive terminal on the battery. Repeat with the negative lead to the negative terminal. If you’re using a multi-bank charger to charge multiple batteries, repeat the step with each battery.

Step 3: Connect Your Charger To Your Power Source

Next you need to connect your charger to your power source. This could be an extension cable or wall outlet. Some larger boats may have an outboard motor and alternator which a charger can be connected to, but if you don’t have a generator or you have a kayak, you’ll probably need to use a power outlet.

Step 4: Switch On The Power

Once all your charger leads are connected to your battery you can switch the power on the charger. Your charger should be able to tell you if your batteries are charging or if there’s a problem with them or the connection.

Most on-board chargers will have built-in technology that can assess how much charge your battery needs and can automatically stop charging when the battery is full, or deliver a trickle charge when needed to keep it topped up.

Portable Chargers

Step 1: Remove Your Battery

If your battery is in an awkward area for charging it might be easier to remove the battery from its location so that it’s easier to connect to the charger. Make sure all your electronics are disconnected from the battery before you connect the charger.

Step 2: Connect Your Charger

Attach the leads from the charger to the corresponding terminals on your battery. If you have more than one battery and your charger has only one bank, you’ll need to repeat the steps for each battery.

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Step 3: Connect To A Power Source

Using an extension cable if necessary, plug your charger in so that it’s connected to a power source.

Step 4: Switch On Your Charger

Turn on the power switch on your charger. Your charger should now be delivering current to your battery. Depending on your charger, you may need to set the amps to the correct level for your battery. However, some chargers may do this automatically.

Step 5: Keep An Eye On Your Charger

It can be a good idea to keep an eye on the level of charge to avoid overcharging or overheating.

When the battery is full, turn off the charger at the power source and then disconnect the charger from the battery before reconnecting the battery to your trolling motor.

Solar Chargers

Step 1: Position Solar Panel In Sunlight

Before you start charging, it’s a good idea to make sure the solar panel of your charger is set-up in direct sunlight so that it can absorb maximum energy.

Step 2: Disconnect The Battery From Your Motor

To avoid damage to your trolling motor, disconnect the trolling motor from the battery.

Step 3: Attach Your Charger To Your Battery

Using the cables attached to your charger, connect them to your battery. The positive cable should be attached to the positive terminal on the battery, and the negative cable to the negative terminal.

Step 4: Turn The Power On

Your solar charger should have a power switch. Turn this on so that you can deliver current from the solar panel to the battery. This can often be slow.

Final Words

When you’re charging your trolling motor battery remember to stay safe and make sure that all your electronics are disconnected from the battery before you connect the charger.

It can also be safer to connect your charger to the battery before you plug the charger into the power socket.

Let us know your thoughts on this guide and share it if you think it could help anyone else.

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