Trolling Motor Lithium Battery Runtime Guide

To estimate how long your trolling motor batteries will last on the water, you need to know two things: the battery's amp-hour (Ah) rating and the trolling motor's current draw. While battery runtime can vary, understanding these factors lets you calculate an accurate estimate. In this article, we’ll show you how to do just that and how to extend your battery’s life for longer use.

How to Calculate Trolling Motor Battery Runtime?

To calculate how long your trolling motor battery will last, it’s essential to understand two key terms:

Trolling Motor Battery's Amp-Hour (Ah) Rating

This indicates how much energy a battery can store and provide over time. For example, a 100Ah battery can supply 10 amps of current for 10 hours, or 20 amps for 5 hours in a full charged cycle.

Trolling Motor's Current Draw

This refers to how much current (in amps) the trolling motor consumes while operating.

Now, to calculate the run-time, you simply divide the battery’s amp-hour (Ah) rating by the motor’s current draw (A):

Runtime (hours) = Battery Capacity (Ah) ÷ Motor's Current Draw (A)

For example, a 40 lbs thrust of trolling motor typically draws around 42 amps at full throttle. If you’re using a 100Ah battery, the calculation would be:

100Ah ÷ 42A ≈ 2.38 hours

So, with a 100Ah battery, you could expect about 2.38 hours of run-time at full throttle with a 40 lb thrust trolling motor.

On the other hand, a 55 lb thrust trolling motor generally draws around 50 amps at full throttle. Using the same 100Ah battery:

100Ah ÷ 50A = 2 hours

In this case, with a 100Ah battery, you would get around 2 hours of run-time at full throttle with a 55 lb thrust trolling motor.

Factors that Affect Trolling Motor Battery Runtime

While the basic calculation is straightforward, several factors can influence the actual battery run-time in real-world conditions. These factors include:

• Motor Speed and Thrust Level: The faster the trolling motor runs, the more power it draws. Higher thrust settings typically use more amps.
• Battery Condition and Age: As a battery ages, its capacity to hold a charge decreases, especially a lead-acid battery. A well-maintained, new battery will provide better run-time than an older or poorly maintained one.
• Trolling Motor Voltage: Higher-voltage motors, such as 24V or 36V, typically draw less current for the same thrust compared to lower-voltage motors like 12V.
• Water Conditions: The type of water you’re navigating can significantly affect run-time. Calm water requires less effort from the motor, while choppy or turbulent water increases the motor's load, leading to higher current draw. 
• Wind Conditions: In strong winds or headwinds, the motor needs to work harder to maintain the boat's position or navigate against the wind, increasing power consumption and reducing battery runtime. Conversely, in calm wind or tailwind conditions, the motor uses less energy, leading to longer runtime.
• Weight Load: The heavier the load your boat carries (including passengers, gear, etc.), the harder the motor has to work. This increases the motor’s current draw and reduces battery run-time.
• Ambient Temperature: Extremely cold or hot weather can affect battery performance. Cold temperatures, in particular, temporarily reduce battery capacity, leading to shorter run-times.
• Motor Efficiency: The efficiency of the motor itself plays a role. High-quality, energy-efficient motors tend to draw fewer amps for the same thrust, extending the battery runtime.

How to Extend Trolling Motor Lithium Battery Runtime?

Maximizing the runtime of your trolling motor lithium battery ensures you spend more time on the water without interruptions. Here are some effective tips to extend your battery’s running time:

• Use Lower Power Settings: If full thrust isn’t necessary, run your motor at lower speeds setting to reduce the current draw and extend runtime.
• Optimize Thrust Levels: Adjusting the thrust level based on your needs can lead to substantial power savings. It's advised to cruise at a moderate thrust level uses less power than constantly operating at full thrust.
• Reduce Weight Load: Minimize unnecessary gear to decrease the weight load and extend your battery’s runtime. Lithium batteries could save a lot of weight and space for your boat.
• Plan Your Route Efficiently: Plan your routes to avoid unnecessary detours and minimize the distance traveled, which helps conserve battery power.
• Monitor Battery Capacity Usage: Keeping an eye on your battery’s charge level allows you to manage power consumption effectively. Some advanced trolling motor batteries like Redodo Bluetooth batteries are allowed to monitor battery status via mobilephone App.
• Choose the Right Battery Capacity: Selecting a battery with a higher amp-hour (Ah) rating, if you plan to longer trips on the water. A larger-capacity battery can provide more energy storage, directly increasing the potential runtime.
• Prepare a Backup Battery: If your boat is equipped with electrical accessories such as lights, fish finders, and radios that also require power, it's essential to have a dedicated battery for them. This ensures that your trolling motor battery has enough power exclusively for powering the trolling motor.

6 Best Long-Lasting Trolling Motor Batteries

Upgrading your trolling motor battery to lithium can significantly extend runtime, as lithium batteries are designed for deeper discharges and have a longer lifespan than lead-acid batteries. Here are some trolling motor batteries with notable advantages in runtime and performance:

Redodo 12V 100Ah Battery with Low Temp Protection

As one of the best 12V 100Ah lithium battery for trolling motor, the battery is perfect for trolling motors with thrust ratings between 30-70 lbs. It provides up to double the runtime of traditional AGM batteries, while weighing 1/3 less (only 22.16 lbs total), improving boat speed and efficiency.

It also features low-temperature cutoff protection, automatically stopping charging below 32°F (0°C) to prevent damage, and resuming when temperatures rise above 41°F (5°C), making it an ideal marine battery for cold conditions.

Built with high-performance LiFePO4 cells, the Redodo lithium trolling motor battery delivers 4000+ cycles, lasting up to 10 years, far surpassing the lifespan of typical AGM batteries of 2-3 years.

Redodo 12V 140Ah Bluetooth Lithium Battery

The Redodo 12V 140Ah Bluetooth Group 31 lithium battery is one of the best trolling motor battery choices available, designed for trolling motors with thrust ratings between 30-70 lbs. It provides 40% more capacity than a standard 100Ah battery without taking up extra space, ensuring extended trolling motor runtime.

This battery also features Bluetooth monitoring, allowing you to track battery temperature, SOC (State of Charge), voltage, current, and overall battery health from your smartphone.

Equipped with a 150A BMS, it delivers a 1920W high power output for larger appliances on your boat. Its fast-charging capability allows it to fully recharge in about 2 hours, making it perfect for long days on the water.

Redodo 12V 100Ah Group 31 Bluetooth Battery

The Redodo 12V 100Ah Group 31 Bluetooth battery is an ideal choice for trolling motors with thrust ratings between 30-70 lbs. With a high energy capacity of 1280Wh, it ensures reliable performance for extended periods on the water.

The battery is also equipped with Bluetooth 5.0 function, allowing you to easily track battery status, including remaining capacity, voltage, and cycle count, through the Redodo app. The remote-control feature allows for convenient discharge management and power-off control.

Designed with an IP65 rating, this battery is protected against moisture, dust, and salt spray, making it highly durable and perfect for marine environments.

Redodo 12V 100Ah Group 24 Bluetooth Battery

The Redodo Group 24 size lithium battery is an excellent choice for trolling motors up to 70 lbs thrust. It features Bluetooth 5.0, allowing you to monitor key metrics such as capacity, voltage, and cycle count via the Redodo app, with remote control for easy discharge and power management.

At just 22.16 lbs, it’s 65% lighter than conventional AGM batteries, providing more usable capacity with less weight. Thanks to top-grade LiFePO4 cells, the battery offers over 4000 cycles at 100% DOD, ensuring long-lasting performance.

With an IP65 rating, this battery is resistant to moisture, dust, and salt water, making it perfect for both marine and outdoor use. The BMS offers full protection against overcharge, over-discharge, overcurrent, overheat, and short circuits, ensuring safe and reliable operation.

Redodo 24V 50Ah Lithium Trolling Motor Battery

The 24V trolling motor battery is designed for 24V trolling motors, delivering max power for trolling motors up to 100 lbs of thrust with a continuous 60A discharge current.

At just 21.2 lbs, the battery is the lightest and most compact Group 24 trolling motor battery available, offering portability without sacrificing power.

Built with EV-grade cells, it provides over 4,000 cycles and features advanced BMS protection for safe operation. With Bluetooth monitoring, you can track charge, cycles, and health status while managing discharge and power-off settings easily.

Redodo 36V 50Ah Lithium Trolling Motor Battery

The 36 volt lithium trolling motor battery is perfect for 36V trolling motors with 100-120 lbs of thrust. It provides a steady 50A discharge, 60A for up to 30 minutes, and a 250A peak surge, ensuring reliable power for high-demand motors.

Weighing only 33.14 lbs with 1920Wh of energy, it’s 70% smaller than three 12V 50Ah lead-acid batteries, saving space and simplifying setup.

The 50A BMS protects against overcharge, over-discharge, over-current, short circuits, and high temperatures. It also features pre-charge functions, automatic recovery within 30 seconds, and enhanced resistance to moisture and salt spray.

Conclusion

To have a better boat experience and maximize your trolling motor’s performance, it’s crucial to understand how to calculate battery runtime and recognize the key factors that affect it.

Redodo specializes in high-quality and durable LiFePO4 batteries for marine, RV, or off-grid use. Visit Redodo to find the perfect trolling motor battery for your needs today and enjoy longer boat trips.

FAQs on Trolling Motor Lithium Battery

Is lithium battery good for trolling motors?

Yes, lithium batteries are ideal for trolling motors due to their high energy efficiency, long lifespan, and lightweight design. They provide consistent power, require less maintenance, and are more reliable than traditional lead-acid batteries.

What size lithium battery do I need for a 55lb trolling motor?

For a 55lb thrust trolling motor, a 12V 100Ah battery is typically sufficient for most recreational uses. If you want longer runtime, you might consider a larger trolling motor battery size for larger capacity like 12V 200Ah or 12V 300Ah battery.

Can I leave my trolling motor battery plugged in all the time?

It’s not recommended to leave your trolling motor battery plugged in constantly. While lithium batteries have built-in BMS protections, overcharging or maintaining a full charge for extended periods may reduce battery life. It’s best to unplug when fully charged or use a smart charger with overcharge protection.

Read More:

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