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What Size Battery for Trolling Motor [Type & Size]

Jun 07, 2024

Selecting the correct battery size for your trolling motor is crucial for maximizing performance and efficiency during your boating adventures. In this thorough guide, we will delve into everything you need to consider when picking the ideal battery size to match your specific boating needs.

Understanding Trolling Motor Batteries

Types of Trolling Motor Batteries

Trolling motor batteries play a pivotal role in the operation of electric trolling motor setups. They supply the essential power needed to propel the boat, and the choice of battery type can significantly influence your boating endeavors.

There are generally three main types of trolling motor batteries: lead-acid batteries, AGM batteries, and lithium-ion (LiFePO4) batteries. Below, we will delve into the specific advantages and limitations of each type.

Lead-Acid Wet Batteries

The most prevalent type of battery utilized for trolling motors is the lead-acid wet cell battery. Comparable to car batteries, these batteries have been prevalent in the market for an extended period. While certain lead-acid wet cells are tailored for deep cycle marine applications, they do not deviate significantly from standard car batteries. Despite their widespread availability, they are considered outdated technologically, with superior options now accessible.

Opting for a lead-acid wet cell battery for your trolling motor requires careful consideration and precautionary measures prior to purchase and installation. The installation process should be approached with care and in the correct sequence.

One notable concern is the risk of acid spillage during the filling process with distilled water, posing potential hazards to you, your vessel, and the environment. Although these batteries are cost-effective and functional, their usage is generally discouraged, particularly for marine vessels, due to safety considerations.

Advantages of Lead Acid Wet Batteries:

  • Affordable
  • Widely available
  • Easy to find replacement parts
  • Can handle shallow discharges


  • Require regular maintenance, such as filling with distilled water and cleaning terminals
  • Shorter lifespan compared to other battery types
  • Heavy and bulky

AGM Batteries

AGM batteries have risen to prominence as the preferred choice for marine applications, thanks to their distinctive design and safety features. Unlike conventional lead-acid batteries, AGM batteries are fully sealed and spill-proof.

The primary divergence lies in the internal composition of these batteries. While lead-acid batteries rely on hydrochloric acid and lead plates, AGM batteries utilize glass mats and a gel substance to facilitate the chemical reactions responsible for storing electrical energy. This construction not only enhances the battery's performance but also eliminates the risk of leakage, rendering it a dependable option for diverse applications, including bass fishing in wet conditions.

The hermetically sealed nature of AGM batteries is particularly pivotal for preserving their long-term health and ensuring safe operation. In contrast, even a minor loosening of one of the cell caps in a lead-acid battery can lead to leakage. This inherent vulnerability is absent in AGM batteries, establishing them as a trusted choice for consumers in search of a reliable and hassle-free power source.


  • Longer lifespan compared to traditional lead-acid batteries
  • Virtually maintenance-free
  • More resistant to vibration and shock
  • Can handle deep discharges


  • More expensive than traditional lead-acid batteries
  • Still heavy

Lithium Batteries

Lithium batteries boast remarkable power and impressively light weight. One of their standout advantages is their consistent power discharge curve, ensuring peak power output until the battery is fully drained. For instance, while a conventional 12V 100Ah lead-acid battery weighs 60-70lbs, the Redodo 12V 100Ah LiFePO4 lithium Trolling Motor battery weighs a mere 22.15 lbs. Additionally, it features built-in low-temperature protection.

Compared to traditional counterparts, which can weigh approximately six pounds and occupy considerable space, lithium batteries are compact and easily fit into tight compartments. They come in various sizes and amp hour ratings, enabling boat owners to select the most appropriate battery for their vessel.

For kayak fishing enthusiasts, opting for a lithium battery is highly recommended. Their compact size and light weight have minimal impact on the kayak's performance. Although they may come with a higher price tag, they are widely regarded as the optimal choice for most kayak setups. In fact, many leading trolling motors for kayaks are now outfitted with lithium batteries.

Despite their higher cost, lithium batteries are gaining popularity for trolling motor applications.


  • Longer lifespan in contrast to traditional lead-acid batteries.
  • Lightweight and compact
  • Maintenance-free
  • Can handle deep discharges


  • Expensive
  • Requires specialized charging equipment
  • May not be compatible with all trolling motors on the market

In conclusion, choosing the right trolling motor battery hinges on several factors including cost, lifespan, and maintenance demands. Lead-acid batteries offer affordability but necessitate frequent maintenance, while AGM batteries offer longer lifespan at a higher cost. Lithium-ion batteries represent the pinnacle of advancement but come with a premium price. Understanding the advantages and limitations of each battery type empowers you to make a well-informed decision when selecting the perfect trolling motor battery for your setup.

Factors to consider when choosing a trolling motor battery

When choosing a trolling motor battery, it's essential to consider crucial factors beyond just the battery types. One such factor is the battery capacity, measured in ampere-hours (Ah), which determines the amount of energy the battery can store and supply to the motor. Higher capacity batteries offer longer run times but are heavier and more costly.

Another critical factor is the battery voltage, which should align with the power requirements of the trolling motor. Typically, trolling motors utilize either 12-volt or 24-volt batteries, depending on their power needs. Incorrect voltage usage can potentially damage the motor or diminish its efficiency.

For trolling motors with up to 55 pounds of thrust, a single 12V battery suffices. More powerful motors, up to 80 pounds of thrust, necessitate two 12V batteries wired in series to deliver a total of 24 volts. The most robust trolling motors generating over 80 pounds of thrust typically require three 12V batteries wired in series to yield a total of 36 volts. Explore further about LiFePO4 Lithium Batteries in Series & Parallel to optimize your setup.

Boat weight and corresponding battery weight dimensions

It's important to highlight that certain trolling motors are specifically engineered to operate with particular battery types, underscoring the significance of consulting the manufacturer's recommendations before purchasing a battery.

Maintenance of your battery remains paramount, regardless of its type. For lead-acid batteries, routine upkeep such as checking fluid levels and cleaning terminals is indispensable for maximizing performance and lifespan. AGM batteries demand less maintenance but should undergo periodic assessments regarding charging and storage conditions. Lithium-ion batteries entail minimal upkeep but necessitate charging using a compatible charger to prevent damage.

Choosing the optimal battery for your trolling motor hinges on your unique requirements and budget. It's crucial to factor in considerations such as capacity, voltage, and compatibility with your motor, alongside weighing the pros and cons of each battery type. Diligent maintenance practices can significantly contribute to prolonging your battery's lifespan and ensuring peak performance.

What Size Battery is Suitable for Trolling?

How Does a Battery Size Affect a Boat’s Performance

Selecting the correct battery size for your boat is essential to ensure optimal performance and safety on the water. The battery's size directly influences the boat's electrical system, engine performance, fuel consumption, and overall stability. Utilizing an improperly sized battery can strain the engine, leading to increased fuel consumption, and may cause damage to the boat's electrical components, resulting in appliance malfunctions and potential hazards such as fluid leaks, sparks, and overheating.

Both oversized and undersized batteries can have adverse effects on the boat's performance and battery longevity. Oversized batteries can exert unnecessary strain on the electrical system, potentially causing damage and reducing efficiency. Conversely, undersized batteries may fail to deliver adequate power for the boat's electrical demands, resulting in shortened run time or complete power loss.

Seeking advice from experts or consulting the boat manufacturer is crucial to determine the appropriate battery size for your specific boat model. Consider factors such as the power requirements of your electrical systems, desired run time, weight distribution, and budget when selecting a battery size. By taking these considerations into account, you can ensure that your boat operates efficiently and safely.

Factors to consider when choosing the right battery size

  1. Boat size and weight: The dimensions and mass of the boat play pivotal roles in determining the appropriate trolling motor battery size. Larger vessels necessitate batteries with higher amp-hour (Ah) ratings to supply sufficient power to the trolling motor for extended durations.
  2. Trolling motor thrust: The thrust output of the trolling motor is another critical factor influencing the required battery size. Greater thrust demands more power from the motor, thus necessitating a larger battery capacity to meet the power requirements adequately.
  3. Fishing conditions: Environmental factors such as wind strength and water currents can significantly impact the power demands of the trolling motor. In the presence of strong winds or currents, a greater power output is required, leading to the necessity for a larger battery size to accommodate these heightened power demands.

Battery Size for Trolling Motor

The most prevalent battery group sizes for trolling motors include 24, 27, and 31. Nevertheless, determining the appropriate size hinges on factors such as your boat's dimensions, cargo weight, and the power requirements of the motor.

For smaller boats with lighter loads and less powerful motors, a group 24 battery may suffice. Group 24 batteries typically measure approximately 10 x 6.88 x 9.94 inches and boast a capacity of around 70-85 Ah. However, the Redodo group 24 LiFePO4 battery boasts a capacity of 100Ah.

Lithium battery vs AGM battery

For larger boats carrying heavier loads and equipped with more powerful motors, a group 27 or 31 battery may be indispensable. Group 27 batteries generally measure about 12 x 6.75 x 8.88 inches and offer a capacity of around 90-105 Ah. Meanwhile, group 31 batteries are even larger, with dimensions typically around 13 x 6.81 x 9.44 inches and a capacity ranging from 100-125 Ah. Below is the BCI battery size format for reference.

group battery size chart

Advantages and disadvantages of using larger or smaller batteries

Opting for a larger battery undoubtedly grants more power and extended run times for the trolling motor. However, the drawback lies in the increased weight and bulkiness of larger batteries, potentially affecting the boat's overall performance and maneuverability.

Conversely, smaller batteries boast lighter weights and are easier to handle, yet they may fall short in providing adequate power for prolonged usage. Hence, it's imperative to strike a delicate balance between battery size and the boat's weight, thrust capacity, and prevailing fishing conditions to ensure optimal performance.

Thus, finding a battery that strikes the perfect equilibrium between size and performance, considering factors such as boat weight, thrust capacity, and fishing conditions, becomes paramount. The solution lies in upgrading to a LiFePO4 battery, renowned for its high energy density and lighter weight, offering an optimal balance of power and maneuverability.

12V 100Ah Lithium battery vs AGM battery

Battery Maintenance and Care Tips

To guarantee the peak performance, durability, and safety of your electric trolling motor system, it's crucial to prioritize the maintenance and upkeep of your trolling motor batteries. Here are some tips and guidelines to assist you in this endeavor:

Charging Techniques:

Using a charger tailored to your battery type is crucial for ensuring peak performance and preventing potential damage. Ensure that the charger aligns with the voltage of your battery. If uncertain, refer to the table below for guidance. Avoid overcharging, as it can diminish battery lifespan or lead to damage. Charge the battery after each use and avoid leaving it in a discharged state for prolonged periods. Can a LiFePO4 battery be charged with a standard charger? Read on to discover the answer!

lithium battery charging voltage

Battery Storage Tips

Ensuring the proper storage of your battery is essential for maintaining its longevity and performance. Store the battery in a cool, dry location, shielded from direct sunlight and extreme temperatures.

Additionally, it's advisable to disconnect the battery from the trolling motor before storage. For flooded lead-acid batteries, maintain appropriate water levels. If storing the battery for an extended duration, fully charge it before storage and periodically recharge it.

Signs of a Failing Battery

Vigilance for indicators of a failing battery is paramount to sidestep safety risks and uphold peak performance. Such signs may encompass challenges in starting the trolling motor, diminished power output, sluggish or incomplete charging, bulging or distorted battery casing, and leaks or corrosion near the terminals. If any of these signs emerge, it could indicate the need for battery replacement or necessitate professional intervention.

Choosing The Right LiFePO4 Battery for Your Trolling Motor

Voltage of Motor Motor Thrust Recommended Max Amp of Batteries Recommended Redodo LiFePO4 Batteries Recommended Reasons
12V 20 ~ 30 lb 50A Redodo 12V 50Ah Lithium Battery Cost-effective
12V 30 ~ 70 lb 100A Redodo 12V 100Ah Lithium Battery Cost-effective, Low-temp, Lighter
24V 70 ~ 100 lb 100A Redodo 24V 100Ah Lithium Battery Cost-effective
36V 100 ~ 120 lb 100A

3* Redodo 12V 100Ah Lithium Battery

3 batteries in series

Below is a summary table presenting the recommended Redodo LiFePO4 lithium batteries, categorized by motor voltage, motor thrust, and the maximum recommended amperage of the batteries. Each recommendation is accompanied by specific justifications. Explore Redodo Trolling Motor Batteries to discover and select your ideal battery.


To wrap up, the selection of the appropriate battery size for your trolling motor is paramount to ensure peak performance and durability. Utilizing an incorrectly sized battery can result in diminished power output, shortened battery lifespan, and potential safety risks. Hence, it's imperative to factor in considerations such as motor thrust, boat weight, and usage patterns to determine the ideal battery size.

As elaborated earlier in this discourse, the optimal approach to selecting the right battery size for your trolling motor is to adhere to the manufacturer's recommendations or seek guidance from a knowledgeable expert. Furthermore, it's crucial to diligently maintain and care for your battery by adhering to the charging, storage, and maintenance protocols outlined herein.

By dedicating attention to choosing the correct battery size and properly caring for it, you can enhance the efficiency and reliability of your trolling motor system. Therefore, do not underestimate this critical aspect of your boating journey and make the appropriate battery selection today! Discover more about experience the power of LiFePO4 and share your story to get 5% off from Redodo.