What Size Battery For Trolling Motor？
Selecting the right battery size for your trolling motor is essential for reliable performance and avoiding issues like short run time or excess weight. This guide covers battery types, key factors, capacity calculations, and upgrade options to help you choose a suitable setup, with a focus on lifepo4 batteries for their efficiency in marine applications.
Understanding Battery Types for Trolling Motors
When picking a battery for your trolling motor, start by reviewing the main types available.
Lead Acid Batteries
such as flooded lead acid batteries and absorbed glass mat versions, serve as entry-level choices for many users.
Flooded lead acid batteries need periodic fluid checks and can leak if tipped, which raises concerns in marine settings, potentially causing acid corrosion on boat surfaces in bumpy waters.
Absorbed glass mat batteries, on the other hand, are sealed to prevent spills and resist vibrations from waves or rough handling, but they still limit discharge to around 50% to maintain battery life.
Lifepo4 batteries
These LiFePO4 batteries allow for discharge rates up to 80-100% to provide more usable energy without risking battery damage, and their self-heating feature helps maintain performance when used in cold environments, providing an alternative solution for deep cycle batteries in trolling motor installations.
For example, 12V lithium batteries weigh much less than comparable lead-acid batteries, making them easier to install on small boats. These batteries can last for thousands of uses, supporting over 3,000 charge and discharge cycles, making them ideal for frequent trips out to sea.
Despite their higher initial cost, lithium batteries can achieve long-term savings of 2-3 times that of lead-acid batteries by reducing the number of replacements.
Factors to Consider When Choosing a Trolling Motor Battery
To help you choose the best trolling battery for your motor needs and sailing conditions, here are the main factors you need to carefully evaluate to ensure compatibility, performance, and longevity.
Voltage Compatibility
Trolling motors require specific voltage settings. Common thrust motors are available in 55lbs and 80lbs. Different thrusts have different battery voltage requirements. Common battery voltage options are 12V, 24V, and 36V. Matching the battery voltage to the motor requirements can effectively prevent inefficiency or damage.
Amp Hour Rating
The ampere-hour rating, also called Ah, determines how long the battery can power a motor. Higher ratings extend run time but increase size and cost.
For instance, a 100 amp hours lithium battery supports 4-6 hours at moderate speeds, while lead-acid may require double the capacity due to its 50% discharge limit. Therefore, you need to choose batteries with different capacities (Ah) according to your frequency of use.
Thrust and Operating Conditions
Motor thrust, measured in pounds (lbs), dictates power needs. Higher thrusts (e.g., 70+ lbs) draw more amps, especially in challenging conditions like strong winds or currents, which can increase demand by 20-50%. A larger capacity battery ensures consistent performance in such scenarios, preventing unexpected power drops during fishing or navigation.
Boat Size and Load
Whether you're kayaking, fishing, or sailing, the size and weight of your boat will influence your battery choice. Heavier boats require larger batteries to maintain power and avoid draining quickly.
For example, a boat weighing less than 2,000 pounds might be able to get by with 24 lead-acid batteries, while a larger boat might need 31 batteries to get plenty of power. You can also choose a 12V 100Ah lithium battery, which has the size and energy density to meet your travel needs.
Maintenance Requirements
Battery types vary in upkeep. Lead acid wet batteries require regular fluid checks and terminal cleaning, while absorbed glass mat batteries need less but still periodic attention. LifePO4 lithium batteries require no maintenance, only proper charging and proper storage and use according to the manufacturer's manual.
Environmental Factors
Cold weather or prolonged exposure to water can affect battery performance, so look for lithium batteries with self-heating features to maintain output at low temperatures, and higher waterproof ratings (such as IP67) to protect against splashing water. Be sure to consider your sailing environment and choose a battery that can withstand the environment it is used in.
What Size Battery is Suitable for Trolling Motor
Choosing the right battery size for your trolling motor involves ensuring it fits your boat's compartment and meets power demands.
Battery size includes both physical dimensions and group standards, such as Group 24, 27, and 31, which are common in marine applications. These groups define standardized sizes and capacity ranges, helping you match batteries to vessels like kayaks, fishing boats, or sailboats.
Physical Fit and Group Standards
Common marine battery groups include 24, 27, and 31, offer distinct dimensions and capacities, always measure your boat’s battery compartment to avoid installation issues.
- Group 24 batteries, typically around 10 x 6.88 x 9.94 inches, suit compact setups like kayaks or small fishing boats under 2,000 pounds, delivering 70-100 amp hours.
- Group 27 batteries, at approximately 12 x 6.75 x 8.88 inches, work for mid-sized fishing boats with moderate loads, offering 90-105 amp hours.
- Group 31 batteries, measuring about 13 x 6.81 x 9.44 inches, handle larger vessels or sailboats, providing 100-125 amp hours.
Lithium batteries within these groups are often more compact or offer specialized designs. For example, a LiFePO4 12V 100Ah battery might fit Group 24 dimensions but provide equivalent power to a larger lead-acid Group 27 due to deeper discharge, yielding 20-30% more usable capacity.
Some lithium models, like mini 100Ah versions, shrink further to around 10.23 x 5.23 x 8.95 inches, ideal for space-constrained kayaks. Always verify dimensions against your compartment and check for features like handles for easy installation.
How to Calculating Battery Capacity for Trolling Motors
Estimating the amp hour rating for your trolling motor involves straightforward math tied to usage patterns.
Identify the motor's amp draw, around 30-50 amps at max for 12V models, less at cruising speeds, then multiply by expected hours of operation.
For a setup averaging 25 amps over 5 hours, aim for at least 125Ah, factoring in discharge limits, you can also use the online calculator tool to calculate the required battery capacity based on your usage needs.
Deep cycle batteries like lifepo4 allow near-full use, so adjust calculations accordingly, for lead acid, multiply needed Ah by 2 due to 50% limit, for lithium, add a 1.2 buffer.
Include a 20-30% extra for unexpected draws from weather or accessories, such as calm waters (base calculation) versus windy conditions (increase by 20-50%).
Temgo Battery provided all batteries support real-time monitoring via Bluetooth connection application and external display to help you measure current consumption, which helps to adjust the battery according to your daily usage and avoid power outages midway on the water.
The table below provides quick estimates for common thrust levels to guide your calculations.
| Thrust (lbs) | Voltage | Average Draw (Amps) | Lithium Capacity |
|---|---|---|---|
| 30-55 | 12V | 20-30 | 80-150 |
| 70-80 | 24V | 30-40 | 100-200 (series setup) |
| 100+ | 36V | 40-50 | 150-300 (series setup) |
How Does a Different Battery Size Affect a Boat's Performance
The correct battery supports steady performance, keeping the motor responsive across speeds.
An undersized battery can cause voltage dips, leading to reduced thrust and interrupted operation, which might cut short a day on the water.
Oversized batteries, while offering extra run time, add weight that impacts boat balance, speed, and fuel use in mixed-power systems potentially increasing drag by 10-20% in sailboats.
Lithium ion batteries mitigate these issues by packing high capacity into lighter units, preserving handling on fishing boats or sailboats. This balance allows for longer sessions without compromising the vessel's agility or stability in varied conditions.
Upgrade to LiFePO4 Lithium Batteries for Trolling Motors
Today, upgrading to LiFePO4 batteries can effectively solve weight and life issues in trolling motor applications, such as integrated solar compatibility, to extend off-grid use time.
These units often include integrated systems for monitoring and protection, enhancing safety during use, along with built-in low-temperature protection. A 12V lithium battery with 100Ah, for instance, suits mid-thrust motors on fishing boats, with scalable options up to 300Ah for extended needs, compare costs, lithium save over lead acid long-term through fewer replacements.
Lithium trolling motor batteries faster charging speed and deep discharge resistance make them reliable in daily use, and compatibility with common motors adds flexibility.
For yachts or sailboats, models with higher voltages in series provide strong power in a compact size.
Trolling Motor Battery Maintenance and Care Tips
Maintenance of trolling motor batteries requires specific type-specific actions to maintain their performance and charge the battery using the included charger.
Lithium iron phosphate batteries have comparable performance to standard batteries, but also have an advantage in overcharge protection, using the battery management system (BMS) monitoring function to avoid over-discharge of the battery.
Please store the battery in a well-ventilated, temperature-controlled place, the temperature should be below 50°C, avoid extreme environments that may cause battery performance degradation, fully charge before storage, and check every three months.
Lead-acid batteries need to be checked for corrosion issues and the terminals cleaned with a baking soda solution.
Regular checks can extend battery life, reducing the need for early replacements.
Conclusion
Finding the appropriate battery size for your trolling motor comes down to integrating thrust, voltage, and capacity with your boating habits.
Through careful calculations and factor assessments, you can achieve reliable run time and consistent power.
If you're looking to equip your setup, Temgo Battery provides lithium options designed for durability in applications like trolling motors. Such as the 12V self-heating lithium battery with a touchable LCD screen, they offer lightweight construction, often under 25 lbs, fast charging, and extended cycle life for thousands of uses. With built-in battery management systems for safety, a 5-year warranty, free shipping, and a 30-day guarantee, Temgo batteries suit fishing boats, kayaks, and more.
