What Size Marine Battery Do I Need for Trolling Motor

When you realize that your old trolling motor marine battery needs to be replaced by a new one. But you are confused about what size marine battery do i need for trolling motor, here is my comprehensive advice to guide you through choosing the right battery size.

what size marine battery do i need for trolling motor

Marine battery comes in a wide selection of sizes, chemistry, and characteristics. To choose the right battery size you should first consider about your boat. Because your boat may be designed for a very specific size of the battery. But you can put a large battery by changing out the battery box or by using the more available space in your boat. For example, If Your boat using a Group 24 marine battery but it has more space to put a Group 27 marine battery than you can think about upgrading to a larger size.

How to Choose the Perfect Size Marine Battery for Trolling Motor

When you get the measurement of your marine battery case for your trolling motor then you should consider your needs of boating. Generally, in the market you will find three types of marine battery these are

So, at first, you should select which type of battery you need. Because each type of battery has a different purpose. Then, connect the trolling motor to the battery.

However, starting batteries are manufactured to deliver a short and high current burst to start an engine like you need when you are starting an engine gasoline or diesel. Deep cycling batteries are manufactured to use for a longer period. It puts a small amount of energy for a long period of time like your house bank of batteries and a dual-purpose battery is kind of a balance between Starting batteries and Deep cycle battery

what size marine battery do i need for trolling motor

The types of your trolling motor should be in consideration because if the motor is not compatible with the capacity of the battery then it will not work. There are different types of motors available in the market like inboard, outboard, inboard-outboard or i/o and electric trolling motor. Each type of motor has different requirement for the type of battery. For example, outboard, inboard and i/o battery usually require a high amperage battery with plenty of starting power. Generally, people use electric trolling motor for fishing. Fishing boats with trolling motor require a long deep power drains that occur before the battery can be recharged.

The capacity of a battery always comes first. Because the more capacity it has the more power it will be able to discharge. The capacity of a battery is measured in two ways, which are ampere and hours. A 12v marine battery with 40 Amp hours can run a 55-pounds motor with 4 people on board for 1 hour at full speed.

So, the more Volt and Amp hour your battery has the more hour it will last. But if you want to know how long it will last without using this method, simply take two batteries one with full of charge rated at 12v and another 9v battery out of charge then use a boost converter. Count the time in your watch until it gives you the signal.

So when measuring the right marine battery sizes for your trolling motor you should consider all these above factors. Because you don’t want to waste your money by choosing the wrong batteries.

Marine Battery Size Chart for Trolling Motor 

what size marine battery do i need for trolling motor

The most common marine battery sizes are 22NF, 24M, 25, 27M, 31M, 34M, 35, and 65 which are acceptable for different kinds of trolling motors. We include here a chart of several boat batteries size and minimum thrust levels and more. 

Battery Size Battery TypesBoat’s Weight Thrust Level 
12-volt battery Deep Cycle 150030lb
12-volt battery Deep Cycle 200040 to 45lb 
12-volt batteryDeep Cycle 250050 to 55lb
24-volt batteryDeep Cycle 3000 – 350070lb
24-volt batteryDeep Cycle 400080lb
36-volt batteryDeep Cycle 4000+101 to 112lb 

If the 12V and 24V battery batteries have a 100 to 120 Ah amp hours rate, they allow you to run more than three hours. In this case, a higher amp hour rate is good for enjoying more run time of the trolling motor. Don’t forget to charge a deep discharge marine battery timely. Check this article on how to do it.

About This Writer

Liam Jaxon Author pic

Hi, I am responsible for the 'Homeowners Power Solutions' category. My name is Liam Jaxon and a licensed technician with 7 years of experience in vehicle batteries, electrical gadgets, and home appliances. My working experience in different residential & light commercial electrical sectors and the automobile industry helped to acquire vast knowledge in this industry.

Hi, I am responsible for the 'Homeowners Power Solutions' category. My name is Liam Jaxon and a licensed technician with 7 years of experience in vehicle batteries, electrical gadgets, and home appliances. My working experience in different residential & light commercial electrical sectors and the automobile industry helped to acquire vast knowledge in this industry.

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