How to Charge A Trolling Motor Battery From the Outboard Motor

How to Charge A Trolling Motor Battery From the Outboard Motor

Mr. Anderson has been waiting for a long time to go fishing with his grandson. But alas! Once in the midway, their trolling motor stopped working!

You might look for other grounds. However, the most common reason behind a dysfunctional trolling motor is a discharged battery. 

Having a die-out battery in the middle way of your expedition is a nightmare. This is why it’s essential to know about charging trolling motor battery. If you’re using an outboard motor, you can already do the job with the help of the outboard motor. 

But, before we know ‘how to charge a trolling motor battery from the outboard motor’, it’s also important to get along with outboard motors, different trolling motor chargers, and batteries.

What is Outboard Motor and Trolling Motor Battery? 

Trolling motors aren’t the primary source of power for your boat. They offer the privilege to troll your boat around a certain area above the water. 

To run your boat, you’ll need primary motors that can offer proper propulsion to steer the boat



Outboard motors are a compact system consisting of an engine, jet drive, and a gearbox. Contrary to Outboard motors, many boat owners use inboard motors as well. 

However, these motors remain outside the boat, offering more space within. In most cases, these kinds of motors are the common scenario for fishing. 

You can also use outboard motors as a general power source for your trolling motor. In our guide today, we’ll learn about how to charge trolling motor batteries from outboard motors. 

Types of Trolling Motor Batteries 

Trolling motors can be charged with 12V, 24V, or 36V deep cycle batteries. However, the 12V deep cycle marine battery is the most popular choice of all. 

This is because 12V deep cycle trolling batteries have optimum discharge periods (4+ hours), and they’re quite affordable as well. 

Both 24V and 36V, like lithium trolling motor batteries 24V and 36V lithium batteries, are more powerful and can last longer than 12V. 

However, 12V deep cycle batteries are worth the shot due to their affordability and availability. 

In this section of our article, we’ll talk about three types of deep cycle batteries. 

  1. Flooded Wet-Cell

For trolling motors, flooded wet cell batteries are one of the most used rechargeable batteries. They’re available in different sizes and shapes. 

Flooded wet cell batteries are made of combining both water and liquid sulfuric acid. They’re more durable and will cost you a few extra bucks. 

However, because flooded wet cell batteries are not sealed, they require more maintenance and bear the risk of exposure.  

  1. AGM Trolling Motor Batteries

AGM, aka absorbed glass mat, is a sealed rechargeable trolling motor battery.

They’re lead-acid deep cycle batteries. Usually, they last longer than other deep cycle batteries. That is being said, AGM trolling batteries can last longer than 2-3 years. Because they’re sealed, AGM batteries prevent abrupt leaks and are more durable as well. 

  1. Lithium-Ion Phosphate Battery

They’re also known as LiPo trolling motor batteries, are preferable to flood wet cell and AGM trolling batteries. They sustain more than other trolling batteries and require zero maintenance. 

It can cover up to 3200 KM of trolling above the water and provides superior durability. Lithium-Ion Phosphate batteries are also cheaper than others. 

If you’re looking for a lifetime energy source (10 years or more) within a very reasonable budget, lithium-ion batteries are the best option of all. The 

In case you’re wondering how to charge a deep cycle battery, our next section will give you all the answers you need. 

How to Charge A Trolling Motor Battery From the Outboard Motor

Does outboard motor charge battery?

Of course, it does.

In case you’re using an outboard motor for propulsion, you can use this motor as the primary source of power for the trolling motor. The outboard motor battery system is quite easy for you to understand. You can do it in two different ways. They’re:

  1. Install A Regulator/ Rectifier

You can simply insert a regulator/ rectifier into your outboard motor. This will convert the AC power-driven by the outboard motor and convert it into DC, which will gradually charge your trolling motor battery. 

Things you’ll need to upgrade your outboard motor are generator coils and regulator or rectifier. 

Generator coils will generate AC from the rotation of your outboard motor. Rectifiers will convert this AC into regulated DC and then charge your battery. 

Fortunately, most outboard motors already have generator coils in them. All you need is a rectifier. To follow the step-by-step procedure on how to install a rectifier on an outboard motor, follow this video tutorial

  1. Using Marine Battery Combiners

Having a battery combiner to charge your trolling motor from the outboard motor is more reasonable than the other options we mentioned above. 

Most outboard motors have a starter battery of their own. Starter batteries gain spontaneous charge from your motor’s alternator. 

Battery combiners help to take some of these charges and share them with your trolling battery. The entire process is easy and less time-consuming. 

There are four nodes in a battery combiner: 2 red nodes and 2 black nodes. All you need to do is simply connect the red nodes to each battery’s positive point and the black nodes to the negative points. 

Alternative Methods to Charge Trolling Motor Batteries 

Besides charging trolling motor batteries from an outboard motor, other trolling motor battery chargers are also available. They’re charging trolling motor with solar chargers, onboard chargers, and portable chargers. 

  • Solar Charger

Solar trolling motor battery charger is an efficient way to charge. Many fishermen find a solar panel for trolling motor batteries wise.

They take direct power from the sun and need to be installed in your boat. However, many boat owners keep solar panels as a secondary option besides other primary sources of energy. But depending on the size and capacity of your motor, you can use it as a main source of energy as well. 

  • On-Board Chargers

These kinds of chargers need permanent installation in your boat. They’re usually plugged into an electrical outlet and thus converting AC to DC power for your trolling motor. 

On-board chargers are also well known for constantly scanning charge rates and the extra protection they serve. 

  • Portable Charger

These small size chargers hold their ground of benefits. They’re more convenient and suitable for small size boats or kayaks. 

Being smaller in size, they serve the benefits of being carried easily and installed in a small place. 

In our opinion, the Schumacher Deep Cycle battery charger is the best one can get within a reasonable budget. It’s for Lead Acid battery type and is available in two different 6V/12V power settings. 

You can also check out the Minn Kota battery charger, a microprocessor-based onboard battery charger for trolling motors. 


  • How to Charge Trolling Motor Battery Without Shore Power? 

Using a stealth charger is the best option when no electricity is available near the area. Stealth chargers charge the trolling motor every time you run the outboard motor. 

You can also try installing solar panels for charging trolling motor batteries while running. In case you’re wondering how to charge trolling motor battery while on the water, connecting the solar panels to the stealth charger is the best option.  

  • What AMP Should I Charge My Deep Cycle Battery? 

This measure depends on the type of deep cycle battery you’re using. If you’re using a 110 amp-h battery, then your charger should be able to provide 11 amps. 

  • How Long to Charge Trolling Motor Batteries? 

The time needed to fully recharge your trolling motor batteries relies on the amp charger you’re using. 

A 5 amp charger will take 10-12 hours to charge an average battery. The amount can vary with a 10/15 amp battery and it will only take 4-6 hours for them. 

  • What Battery Do I Need for My Outboard?

Most outboard motorboats have 12V lead-acid batteries. Lead-acid batteries are considered the best battery for outboard motors. 

  • Does An Outboard Motor Have An Alternator? 

Yes, almost every outboard motor has an alternator built in them. Alternators help to charge the battery of the motor when your outboard engine is active. They also provide essential electrical power when your boat is running. 


An outboard motor is a smart choice for many boat owners. 

To avoid the unfortunate situation where your trolling motor stops working in the middle of the lake, you must know how to charge the trolling motor battery from the outboard motor. 

As we showed multiple ways to charge trolling motor, you shouldn’t worry about going out of choices. 

However, if you found our article useful, do let your friends know as well. 

Anthony Jones
Anthony Jones

Anthony is an expert in fishing and trolling motor equipment, based in Austin. In his free time, he can often be found out on the water, perfecting his fishing techniques and testing out the latest gear.

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