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What Is The Best Battery Size For Trolling Motor? Here Is The Answer

What Is The Best Battery Size For Trolling Motor? Here Is The Answer

If you are just a beginner or an experienced fisherman, there is one thing everyone is aware of precision. Precision is not only achieved by the angler but also by the boat and, more specifically, the trolling motor.

When selecting the type or size of your trolling motor, there are a few steps to follow that should not be taken for granted. It will ensure optimal performance and efficiency of the water. 

In this comprehensive blog, you will learn all about trolling motors, especially the size you need for your boat. 

Trolling Motor Battery Basics

The trolling motor is a crucial component for any electric trolling system. Since they provide the necessary energy to propel the boat forward, selecting the proper size can affect your boating experience. It can impact positively or negatively.

Trolling motor batteries are categorized into lead-acid, AGM, or LiFePO4 batteries. 

Lead-Acid Batteries

 lead acid

This type is the classic example of most trolling motor batteries. For many years, they were the only option in the market. In essence, they are a car battery.

Even though sure lead acid batteries were optimized for marine use, there are not many differences from a regular car battery. Plus, it is well-known that they need to be updated from the rest of the new batteries that can be found in the market nowadays. 

These batteries are by far the most affordable and have a 2-3 years lifespan. It can require some maintenance and is prone to vibration and spillage. 

AGM Batteries

 AGM Batteries

Similar to Lead-Acid, AGM is the new black in marine batteries. They work just like lead-acid batteries but are not spillable as they are entirely enclosed.

There are several critical differences between AGM and Lead-Acid. One is the lifespan, which is longer in AGM batteries. The other difference is the chemical components. While lead acid has liquid acid, the electrolyte in AGMs is absorbed in mats that contact the plates within. As a result, there are fewer spills. 

AGM Batteries are commonly called “maintenance-free” batteries as their sealed nature prevents the need to maintain the acid level within them.

LiFePO4 Batteries 

lifepo4 batteries 

Lithium batteries have become more and more popular for many different reasons.

  1. Longer lifespan (10 years). They double the cycle the previous two batteries have. They are extremely powerful and lightweight, and their DOD (depth of discharge) is flat, which means that you can use 100% of the battery´s power.
  2. Smaller Footprint. Lithium batteries are built up with chemicals that do not affect the environment like previous batteries. You can read more about it by clicking here.
  3. More Power. We just mentioned it, but it is vital to note it. With boats, there is a consistent speed fluctuation. Lithium batteries supply more power due to their negligible voltage drop when rapid acceleration is required.

The only drawback is the cost. They are reasonably more expensive than any other type of battery. However, if you only consider their lifespan, it is an investment.

 Factors To Consider When Choosing A Trolling Motor Battery 


Some factors need to be considered before purchasing any battery. Let´s have a look at the important ones.

Boat Size and Weight

The boat size and weight is the main factor to consider when selecting a battery for your trolling motor battery. So, your first step should be consulting your manufacturer’s specifications for battery size. Otherwise, you can always check the manual’s specifications. 

In that booklet, you will find specifics such as Amps or speed/gear your boat requires. However, when it comes to fishing, it is usual to get oversized motors and larger batteries. This is because it allows you to fight wind and waves and works as secondary propulsion if needed. 

Note: Getting a larger battery will increase the boat's weight and expense. Always consult a specialist if it is convenient for you.

Trolling Motor Thrust

Depending on the thrust the trolling motor generates, it will affect the battery size. The higher the thrusts, the more power the engine will require. As a result, a larger battery is needed to provide enough power.

Fishing Conditions 

These will depend directly on climate, which is not an aspect we can control. However, you will know wind and currents as an experienced fisherman or even living in a specific area. It is essential to notice it since strong winds and currents also require more power. Which again is a larger battery.

Selecting the Correct Battery

selecting correct battery 

Engine Voltage and Power

The engine voltage is always printed on the outside of the engine itself. The information can be found as well in the user manual, as well as the power of the engine. The latter is measured in Watts.

Run Time

This is a more personal decision. The amount of hours you are willing or need your boat to run and at what pace. When you have the estimated run time, you must figure out the power draws in Amps. As a result, you will have the battery formula.

Battery Formula

The battery formula will calculate the Amp-hours your boat requires of the battery. Our Goldenmate batteries indicate the Amp-hours. All Goldenmate batteries are 12V with Amp-hours starting at 10Ah, 20Ah, 100Ah, and 200Ah.

Note: Only Lithium batteries work with the formula. It does not work if you use it with lead batteries. This is so because the capacity is always lower than the one indicated on the battery.

Some Tips

For your safety and the efficiency of the battery, we would recommend the following tips to take into consideration:

  • Do not mix batteries. 
  • If your battery has been used throughout the day, charging it again as soon as possible is better. Because if left discharged, it decreases longevity and performance.
  • Check terminal connectors for signs of corrosion and clean them properly.
  • Store them in a cool and dry place. We have an entire blog about how to store liFePO4 batteries properly.

Final Thoughts

Finding the perfect battery for your fishing boat can be exhausting. You must have the proper information to make an easier decision. Remember that you will find three types of batteries. The class is acid-lead, which needs to be updated. It is more economical but with a lifespan of 2-3 years. The AGM is a better option since they are enclosed, do not leak, and have a longer lifespan.

Last but not least, lithium-iron or LiFePO4 batteries. This type of battery is by far the most expensive but with a longer lifespan, more eco-friendly, and better DOD.

We have more guidelines in regard to why LiFePO4 batteries are the batteries of the future. Click here and find out more.


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