Part 1: Understanding Trolling Motor Batteries
1.1 Types of Trolling Motor Batteries
Trolling motor batteries are crucial for powering electric trolling motors, significantly impacting your boating experience. There are three main types of trolling motor batteries: lead-acid, AGM (Absorbed Glass Mat), and lithium-ion (LiFePO4). Here, we’ll outline the advantages and disadvantages of each type.
Lead-Acid Wet Batteries
Lead-acid wet cell batteries are the most commonly used for trolling motors, similar in design to standard car batteries. While some are optimized for deep-cycle marine use, they largely share technology with conventional car batteries. Although still widely available, advancements in battery technology have introduced more efficient alternatives.
If you choose a lead-acid wet cell battery, keep in mind a few important precautions during installation and use. One significant concern is the risk of acid spills when filling the cells with distilled water, which can pose hazards to you and the environment. While these batteries are affordable and functional, their safety issues make them less suitable for boating.
Advantages of Lead-Acid Wet Batteries:
- Cost-effective
- Widely available
- Easy to find replacement parts
- Can handle shallow discharges
Disadvantages:
- Require regular maintenance, such as topping off water and cleaning terminals
- Generally shorter lifespan compared to other battery types
- Heavy and bulky
In the next sections, we’ll explore AGM and lithium-ion batteries to help you make a well-informed decision.
AGM Batteries
AGM batteries have become a popular choice for marine applications due to their unique design and safety features. Unlike traditional lead-acid batteries, AGM batteries are completely enclosed and non-spillable. Their internal construction utilizes glass mats and a gel electrolyte, which reduces the risk of leakage and enhances performance. This makes them a reliable option for various activities, including bass fishing in wet conditions.
The sealed design of AGM batteries is crucial for their longevity and safe operation. In contrast, even minor loosening of cell caps in lead-acid batteries can result in leaks. This vulnerability is absent in AGM batteries, making them a trusted choice for consumers seeking dependable power.
Advantages:
- Longer lifespan compared to traditional lead-acid batteries
- Virtually maintenance-free
- Highly resistant to vibration and shock
- Capable of handling deep discharges
Disadvantages:
- Higher cost compared to traditional lead-acid batteries
- Relatively heavy
Lithium Batteries
Lithium batteries offer exceptional power in a lightweight package. Their flat power discharge curve enables maximum output until they are fully depleted. For example, a traditional 12V 100Ah lead-acid battery weighs between 60-70 lbs, while a LiTime 12V 100Ah LiFePO4 lithium battery weighs only 22 lbs and features low-temperature protection.The low-temperature protection with a cutoff mechanism to maximize battery life and charging efficiency, keeping you safe and powered even in the coldest conditions.
These compact batteries are perfect for kayak fishing, as they fit easily into small compartments and have minimal impact on performance. Despite their higher cost, they are a top choice for many boaters, with many leading trolling motors for kayaks coming equipped with lithium batteries.
Advantages:
- Longer lifespan than traditional lead-acid batteries
- Lightweight and compact
- Maintenance-free
- Excellent at handling deep discharges
Disadvantages:
- More expensive
- Requires specialized charging equipment
- May not be compatible with all trolling motors
In summary, choosing the right trolling motor battery requires consideration of factors such as cost, lifespan, and maintenance. Lead-acid batteries are budget-friendly but need regular upkeep, while AGM batteries offer extended lifespans at a higher price. Lithium-ion batteries are the most advanced option but come with a significant cost. Understanding the strengths and limitations of each type will help you make an informed decision for your trolling motor system.
1.2 Factors to Consider When Choosing a Trolling Motor Battery
When selecting a trolling motor battery, several key factors go beyond just battery types. Battery capacity, measured in ampere-hours (Ah), indicates how much energy the battery can store and supply. Higher capacity batteries offer longer run times but tend to be heavier and more expensive.
Another critical factor is the battery's voltage, which must match the power requirements of your trolling motor. Typically, 12-volt or 24-volt batteries are used. Using the wrong voltage can damage the motor or reduce its efficiency. For motors with up to 55 pounds of thrust, a single 12V battery suffices. Motors up to 80 pounds of thrust require two 12V batteries in series for a total of 24 volts. The most powerful motors, exceeding 80 pounds of thrust, usually need three 12V batteries in series for 36 volts.

It's essential to check the manufacturer's recommendations, as some trolling motors are designed for specific battery types. Maintenance is also crucial regardless of battery type. Lead-acid batteries need regular checks for fluid levels and terminal cleaning, while AGM batteries require periodic assessments of charging and storage conditions. Lithium-ion batteries demand minimal maintenance but should be charged with compatible chargers to prevent damage.
Choosing the ideal battery for your trolling motor involves considering capacity, voltage, compatibility, and your budget. Proper maintenance can extend battery life and ensure optimal performance.
Part 2: What Size Battery is Suitable for Trolling?
2.1 How Battery Size Affects Boat Performance
Choosing the right battery size is crucial for your boat's optimal performance and safety. The battery's size directly impacts the electrical system, engine efficiency, fuel consumption, and overall stability. An incorrectly sized battery can strain the engine, leading to increased fuel consumption and potential damage to electrical components, resulting in appliance failures and hazards like fluid spills or overheating.
Both oversized and undersized batteries can adversely affect performance and lifespan. Oversized batteries can create unnecessary stress on the electrical system, reducing efficiency and risking damage. Conversely, undersized batteries may fail to provide adequate power, leading to shorter run times or total power loss.
Consulting with experts or the boat manufacturer is vital for determining the appropriate battery size for your model. Consider factors like power requirements, desired run time, weight distribution, and budget to ensure safe and efficient operation.
2.2 Factors to Consider When Choosing the Right Battery Size
Boat Size and Weight: The dimensions and weight of your boat are critical in selecting the right battery size. Larger boats require higher amp-hour (Ah) ratings to maintain power over longer periods.
Trolling Motor Thrust: The thrust produced by the trolling motor directly affects the required battery size. Higher thrust demands more power, necessitating a larger battery.
Fishing Conditions: Wind and current conditions influence power needs. Strong winds or currents increase power requirements, making a larger battery essential.
2.3 Battery Size for Trolling Motor
Common battery group sizes for trolling motors are 24, 27, and 31. The right size depends on your boat's dimensions, the weight being carried, and the motor’s power requirements.

Group 24 Batteries: Ideal for smaller boats with lighter loads, these batteries measure approximately 10 x 6.88 x 9.94 inches and have a capacity of 70-85 Ah. For example, the LiTime Group 24 LiFePO4 battery has a capacity of 100 Ah but only 2/3 Lighter, 1/4 Smaller, 2X energy of 12V100Ah Lead-Acid battery.

Group 27 Batteries: Suitable for larger boats with heavier loads, Group 27 batteries usually measure around 12 x 6.75 x 8.88 inches and offer a capacity of 90-105 Ah.
Group 31 Batteries: These larger batteries measure about 13 x 6.81 x 9.44 inches and provide a capacity of 100-125 Ah.

2.4 Advantages and Disadvantages of Using Larger or Smaller Batteries
Larger batteries deliver more power and longer run times but add weight and bulk, potentially affecting performance and maneuverability. For instance, LiTime offers a 36V battery suitable for motors up to 120 lbs.

On the other hand, smaller batteries are lighter and easier to manage but may not supply sufficient power for extended use. It’s essential to find a balance between battery size and factors like boat weight, thrust, and fishing conditions for optimal performance. Upgrading to a LiFePO4 battery can provide high energy density and reduced weight.

2.5 Is a 12V 20Ah Lithium Battery Good for a Trolling Motor?
A 12V 20Ah lithium battery can work for a trolling motor, but it’s essential to evaluate your specific power requirements to ensure it meets your motor's demands.
1. Runtime
A 12V 20Ah battery offers a total capacity of 240 watt-hours (Wh) (12V * 20Ah). The runtime varies based on the trolling motor's power draw:
- If the motor draws 20 amps, the battery lasts about 1 hour (20Ah / 20A = 1 hour).
- If it draws 10 amps, it lasts approximately 2 hours.
2. Power Requirements
Many trolling motors need more than 20Ah for extended use, especially at higher speeds. For longer outings or increased speeds, consider a battery with a larger capacity, like 50Ah or 100Ah, to ensure adequate runtime. A 12V 20Ah lithium battery is suitable for short trips or light-duty tasks, but a higher-capacity battery is advisable for more demanding use.
Part 3: Battery Maintenance and Care Tips
To maintain optimal performance, longevity, and safety of your electric trolling motor system, focus on battery care. Here are key tips:
3.1 Charging Techniques
Use a charger specifically designed for your battery type to prevent damage and ensure effective charging. Confirm that the charger matches your battery's voltage; refer to the table below if uncertain. Avoid overcharging, as it can shorten battery life. Charge the battery after each use and refrain from leaving it discharged for extended periods.

3.2 Battery Storage Tips
Proper storage is vital for longevity and performance. Store the battery in a cool, dry place, away from direct sunlight and extreme temperatures. Disconnect it from the trolling motor before storage. For flooded lead-acid batteries, maintain the proper water levels. If storing for an extended time, charge it fully beforehand and recharge periodically.
3.3 Signs of a Failing Battery
Monitor for signs of a failing battery to avoid safety risks and ensure performance. Look for difficulty starting the trolling motor, reduced power output, slow or incomplete charging, a bulging or deformed case, and corrosion or leakage around the terminals. If you observe any of these signs, consider replacing the battery or consulting a professional.
Choosing the Right LiFePO4 Battery for Your Trolling Motor

This table outlines the recommended LiTime LiFePO4 lithium batteries based on motor voltage, thrust, and maximum amperage, along with specific reasons for each recommendation. Visit LiTime Trolling Motor Batteries to find your ideal battery.
Conclusion
In summary, selecting the right battery size for your trolling motor is essential for optimal performance and longevity. Using the incorrect size can result in reduced power output, shorter battery life, and potential safety hazards. It's important to consider factors such as motor thrust, boat weight, and usage patterns when determining the appropriate battery size.
As highlighted in this article, the best approach to choosing the right battery is to refer to the manufacturer's recommendations or consult with an expert. Additionally, ensure you maintain and care for your battery by following the charging, storage, and maintenance tips provided here.