How Long Does an Electric Trolling Motor Last? Essential Guide and Factors

Several factors influence how long your trolling motor will last both in terms of its lifespan and runtime out on the water.

This article is going to focus mainly on runtime. To work out how much you have then, you’ll need to remember these key points:

Runtime (hours) = Battery Amp Hour Rating / Motor Amperage Draw

1️⃣ Runtime (hours): How long the battery can keep the motor running. This is measured in hours.

2️⃣ Battery Amp Hour Rating: This tells us how much energy a battery can store. It’s like the size of a fuel tank of gasoline. The bigger the fuel tank, the more energy it can hold and the longer the boat can run. Amp-hours (Ah) are used to measure the energy in a battery.

3️⃣ Motor Amperage Draw: This is the amount of energy the motor uses every hour. It’s like the speed at which the car burns fuel while running. The higher the motor amperage draw, the more energy the motor uses and the faster the battery will run out.

A trolling motor’s runtime ultimately depends on these factors. Let’s take a deeper look at each. 

🔋Battery Runtime and Determining Factors

To calculate the runtime of a trolling motor, you need to know the battery’s amp hour rating and the motor’s amperage draw.

The amp hour (Ah) rating is usually found on deep cycle or marine batteries, while the amperage draw can be checked in the product specifications for your trolling motor. Use the following formula to determine the runtime:

Runtime (hours) = Battery Amp Hour Rating / Motor Amperage Draw

For example, if a motor has a 20-amp draw and a 100-amp-hour battery is used, one can divide the battery’s amp-hour rating by the motor’s amperage draw to calculate the runtime:

100 amp hour rating / 20 amp draw = 5 hours

Remember that this calculation provides an approximate runtime in optimal conditions, and actual runtime may vary due to factors like wind, current, and battery health.

Increasing Battery Runtime

There are several ways to increase the runtime of your trolling motor and make your battery last longer:

  • Choose a high-capacity battery: Opt for higher amp-hour ratings, as this allows for more runtime per charge. Check out this article on batteries for electric trolling motors to see your options.
  • Maintain the battery: Understanding when to charge your trolling motor battery is an essential part of battery maintenance. Properly care for your battery by fully charging it after each use, as suggested by OPTIMABATTERIES. This helps to preserve battery capacity and extend its lifespan.
  • Reduce motor speed: Use your trolling motor at a lower speed, which consumes less energy, ultimately allowing the battery to last longer.
  • Remove excess weight: Lighten your boat by removing unnecessary items, reducing drag and energy consumption.

Implementing these practices can help you to increase the runtime of your electric trolling motor and ensure that your battery lasts longer during each use.

🔌 Connecting Multiple Batteries

To achieve your setup’s desired voltage and capacity, you may consider connecting multiple batteries. 

This is especially relevant when using 24v trolling motors, which require two 12v batteries to operate efficiently. In this section, I’ll discuss connecting two 12v batteries in series and parallel configurations.

Connecting Two 12V Batteries in Series

Connecting two 12v batteries in series will create a 24v system required for 24v trolling motors. To do this, follow these steps:

  1. First, ensure both 12v batteries are of the same type and capacity.
  2. Next, connect the first battery’s positive (+) terminal to the trolling motor.
  3. Use a jumper cable to connect the negative (-) terminal of the first battery to the positive (+) terminal of the second battery.
  4. Finally, connect the second battery’s negative (-) terminal to the trolling motor.

With this configuration, the trolling motor will receive 24 volts of power, enabling it to run as intended.

Connecting Two 12V Batteries in Parallel

If you use a 12v trolling motor but desire a longer runtime, you might consider connecting two 12v batteries in parallel. This will maintain the same voltage (12v) while increasing the system’s amp-hour capacity. To connect two 12v batteries in parallel, follow these steps:

  1. First, ensure both 12v batteries are of the same type and capacity.
  2. Next, connect the first battery’s positive (+) terminal to the second battery’s positive (+) terminal using a jumper cable.
  3. Finally, connect both batteries’ negative (-) terminals together using another jumper cable.

In this configuration, the voltage remains at 12v, but the system’s capacity is doubled, providing a longer runtime for your trolling motor.

Motor Amperage Draw

The amp draw of a trolling motor refers to the amount of electrical current required to operate and directly influences the motor’s battery life. 

High amp draw reduces battery life, requiring more frequent charging or battery replacement, which, in turn, may affect the overall lifespan of the motor. 

Comparing the amp hour rating of the battery and the amp draw can indicate how long the motor can run before requiring a recharge.

Voltage and Amperage Draw

Electric trolling motors come in different voltage configurations, such as 12V, 24V, and 36V systems. The voltage of a trolling motor determines the maximum power and thrust it can deliver.

Operating a motor at its maximum power for extended periods can cause it to wear out faster, while using it at a lower power setting can prolong its life.

The amperage draw, on the other hand, determines the trolling motor’s energy consumption, which affects the battery life.

⚙️ Types of Trolling Motor Batteries

Flooded Lead Acid

Also known as wet-cell batteries, are popular for electric trolling motors. These batteries are affordable and widely available.

They use a liquid electrolyte that surrounds the lead plates, allowing them to produce a consistent, steady power output.

However, they require regular maintenance, such as checking and refilling water levels, and they can potentially spill if not correctly handled or stored.

AffordabilityWeight and size
Wide availabilityShorter lifespan and cycle life

AGM Batteries

These are sealed lead-acid batteries with a special glass mat separator that absorbs the electrolyte.

This design makes them maintenance-free, leak-proof, and more resistant to vibration and temperature fluctuations.

AGM batteries typically have a faster charging rate and longer cycle life than flooded lead acid and gel batteries, which can better support a trolling motor’s power demands.

Keep in mind, though, that AGM batteries can be more expensive.

Low maintenanceHigher initial cost
Spill-proofSensitive to overcharging

Lithium Batteries

Lithium batteries are becoming increasingly popular for trolling motor systems due to their lightweight design and longer lifespan.

Lead-acid batteries typically last around two or three years with regular use, while lithium batteries can last five years or more.

Moreover, lithium batteries do not suffer from sulfation, a common issue with lead-acid batteries when stored for extended periods.

But always exercise caution when using lithium batteries with trolling motors, as running the motor at its highest speeds may cause damage.

Staying at 85% of the motor’s max speed or lower with lithium batteries is recommended.

High energy densityHigher initial cost
Long lifespan & cycle lifeSensitivity to high temperatures

Find out if lithium batteries could be a good choice for you.

Factors Affecting Electric Trolling Motor Lifespan

Battery Life

Battery life plays a significant role in the overall lifespan of the rig. The type of battery used can affect how long the motor will last.

Wet lead acid batteries typically last for 2 to 3 years, sealed AGM batteries for 4 to 5 years, gel batteries for 3 to 5 years, and lithium batteries for 4 to 6 years.

Trolling motor efficiency and how the battery is used and maintained can also significantly impact battery life and motor lifespan.

Trolling Motor Maintenance

Proper maintenance can significantly extend the life of a trolling motor. Regularly inspecting and cleaning the motor, checking for loose connections, and ensuring that the propeller is debris-free will help maintain optimal performance.

If maintenance is an issue for you for any reason, opt for a lithium trolling motor battery, as these are maintenance-free.

Regardless, any well-maintained, high-quality trolling motor can last up to 20 years or longer. In contrast, a poorly maintained motor might experience issues and require replacement after only 5 or 6 years.

🔑 Key Takeaways

Optimizing trolling motor runtime and lifespan involves understanding factors like battery rating, motor draw, and maintenance. Let’s recap:

1️⃣ The equation “Runtime (hours) = Battery Amp Hour Rating / Motor Amperage Draw” is a key tool to calculate the motor’s runtime.

2️⃣ To increase battery runtime, choose a high-capacity battery, maintain the battery’s health through proper charging, reduce motor speed, and remove excess weight from the boat.

3️⃣ Motor amperage draw directly affects battery life, and operating the motor at lower power settings can extend its lifespan.

Nice to e-meet you. I’m Justin, a seasoned sailing journalist and communications pro with more than 25 years of extensive industry experience. And a track record of successfully promoting teams and events on the global stage.