How to Charge a Trolling Motor Battery: Tips and Tricks

(Last Updated On: April 26, 2022)
 How to Charge a Trolling Motor Battery

A time ago, it was hell to charge a trolling motor battery. Batteries had containers, and battery acid was circulating within them during the charge. It was a good method, though it was rather time-consuming.

Besides, a person spent much effort and was exhausted by the process. Fortunately, we live in the epoch of new technologies, and the approach to battery charging has improved greatly.

To charge a trolling motor battery, a person is to be aware of its type to select the best charger. This guide will help you to avoid mistakes and make your trolling motor battery serve longer.

Types of Trolling Motor Batteries

It is impossible to describe one charging method because trolling motor batteries differ. They demand various approaches and knowledge. Today, one can have one of the three following types of trolling motor batteries.

  1. Flooded Cell (FCB)
  2. Sealed Gel (SGB)
  3. Absorbed Glass Mat (AGMB)

The first one is the most popular at the moment. Anglers find FCB easy for charging and exploitation. People use a negative plate to make the battery acid go inside its container. Such a method guarantees an electrical response in the cells of the battery.

Safety hazard deals with the spilled acid that can hurt your skin or eyes. Spilled acid also causes sulfation that does not let a battery accept the charge. So, one must be very careful. Experts recommend multi-stage charging for such batteries. To prevent mistakes, a person should get a smart charger.

Trolling motor batteries
Source: YouTube

The second type of trolling motor batteries also uses acid but it contains the element that makes it thicker to prevent leakage. This battery is simple to charge. Its structure and composition prevent sulfation.

A person should keep in mind that such batteries increase the number of dead cells when overcharged or undercharged. As a result, dead cells complicate the charging of SGB.

This battery demands a charger that needs constant voltage charging with a peak voltage of less than 14.7 V.

The last type is also easy to charge. A person can use onboard chargers, solar panel packs, and outboard charges for it. It does not take much time to fully charge AGMB. Just like with SGB, AGMB is not to be overcharged.

—A person who charges it must control the charging cycle to make the battery serve longer. It needs slow and low charging.

One cannot use a charger for flood cell batteries here because it can result in AGMB overcharge and a shorter life span of the battery.

Things to Consider Before Charging a Trolling Motor Battery

It is not convenient to distract when doing something. That is why a person should consider several things before starting charging a battery.

Select the right charger

First, you should get the correct charger type. Your choice should depend on the speed you want to get. Up to 5 hours of recovery time will demand 15 amps per bank, 4-6 hours – 10 amp/bank while 10 hours of recovery time needs 5-6 amps per bank.

Take everything you need with you

To charge a battery, you will need a clean cloth, a charger, a protective mask, glasses, gloves, tools (pliers, an ampere meter, a spanner), and a power outlet.

Try to charge the battery when not on the water

Sometimes, a person forgets to check the battery and has to do that while floating. Experts recommend consulting a pro to make sure that your charger fits such a process.

Many chargers hurt the battery performance when charging on water. Different batteries and chargers have peculiarities to consider before the purchase. Only some of them can adjust to the situation.

Tools to Use to Charge a Trolling Motor Battery

Tools to use to charge a trolling motor battery
Source: YouTube

First, to check the remaining charge, one must have an ampere meter and a watch to calculate the charging time. One also uses an ampere meter to test the battery after the charge or to see whether the battery is still good or needs replacement.

Second, a person should select the right trolling motor charger.

  • Portable chargers

These chargers are perfect tools because one can easily take them on and off the boat. One should connect it to the battery and charge it by completing the full cycle. After, one will need to disconnect it. Compared to solar panels, they charge faster. Portable chargers are durable and promise comfortable charging conditions. 

  • Solar power supplies
Solar power supplies
Source: Pixabay

They suit sunny weather. The best option is to place it in the highest place to get more sun rays. If you want to charge several batteries, you will need a relay circuit. Gel and AGM batteries demand low voltage.

Consequently, you need a boost converter to guarantee it. Such charging is not good for regions where the weather is often rainy and dull. Lack of sunlight leads to quick discharge or inability to charge the battery to full. 

So, solar packs are perfect for AGMB and SGB but do not fit FCB. One should be patient when dealing with such chargers (because of the sun cycle), but they never lead to overcharge.

  • Onboard charger

A person can find digital (precise but weaker than precision), precision (fast), and DC alternator (extra boost for longer battery life) onboard chargers. Experts recommend choosing the precision one because it fits all the above-mentioned battery types. Other variants are also good, easy-to-use, and do their job quickly and qualitatively.

Third, if you have a flooded cell battery, you will also need a clean cloth in case of acid leakage. It might hurt your skin and eyes, so you will need gloves, a mask, and glasses to keep your organs safe.

Fourth, you must connect and disconnect the battery to the charger properly. So, you must have an appropriate spanner and pliers for that.

Finally, there should be a power supply. You might use the one you like depending on the chosen place. It can be a wall socket or an extension cord.

How to Charge a Trolling Motor Battery: Do’s and Don’ts

Charging the trolling motor battery
Source: YouTube

One must know how to charge a trolling motor battery by keeping in mind the type of charger and battery.

Portable chargers

Step 1. Separate the battery from the electrical supply. Check its surface. It must be clean and dry. Put on protective gears.

Step 2. One-bank chargers fit only one battery. Look at its terminals (+ and -) and connect them correctly with the battery.

Step 3. Connect the charger to the source of power

Step 4. Enable the charge and set it up in case it does not have automatic settings.

Step 5. Observe the charging process to prevent overcharge and unplug it on time. Smart chargers control the time and current. If you don’t have it, control it using a manual guide.

Onboard chargers

Step 1. Check if the surface and connectors are dry and clean. It is better to unplug the motor from the battery for that reason.

Step 2. Connect the charger and the battery. “+” goes to the positive terminal and “-” goes to the negative connector.

Step 3. Plug in a charger using a wall socket or an extension cable.

Step 4. Switch on the charger and wait till the battery is full. Then, unplug it and disconnect it from the battery.

Solar charger

Step 1. Put the charger in the appropriate place to get maximum sunlight.

Step 2. Separate the battery from the motor and check its surface and connectors.

Step 3. Attach the charger to the battery. The positive connector goes to the “+” terminal while the negative one goes to the “-” terminal.

Step 4. Turn on the charger and be patient because it takes much time to finish the process. Unplug it when at the end of charging.


  • test the battery
  • charge the battery after arrival
  • take care of the battery surface and connectors of the charger
  • remember about safety hazards
  • clean the surface and connectors on flooded cell batteries before and after charging to prevent sulfation


  • overcharge batteries
  • undercharge batteries
  • mix battery types (you might accidentally forget charging peculiarities and spoil one of them)
  • apply a speedy charge in case of gel and absorbed glass mat batteries (it damages separators, cells, metal plates)
  • charge the battery in wet places (because of possible short circuit and battery damage)


If you want your battery to serve long, you will have to select the correct charger depending on your battery type. Experts do not recommend using an FCB charger for SGB and AGMB because of different charging speeds.

The best option is to download the manual guide and read it carefully. A manufacturer of a charger and a battery usually mentions all the required information about them.

Remember to be careful and wear rubber gloves when dealing with electricity or FCB. Clean the surface with a soft, dry, and clean piece of cloth to remove the dirt and moisture. You should check the battery to fix its broken connectors or replace it when necessary.

It is essential to unplug the charger on time not to overcharge the battery. Correct exploitation prolongs the life span of both the battery and the charger.

How to Charge a Trolling Motor Battery-1-1

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