Three 12V Batteries vs. One 36V Battery for Trolling Motors: Which is Better?

Choosing the right battery setup for your trolling motor can significantly impact performance, convenience, and overall costs. The two most common configurations are a three 12V battery system wired in series or a single 36V lithium battery. Let’s dive into the differences, benefits, and downsides of each option to help you make an informed decision.

Three 12V Battery Setup

How It Works

In a 3-battery system, three 12V batteries are connected in series to produce the required 36V output for the trolling motor. This setup is widely used and has been the standard for years.

Benefits

  1. Cost-Effectiveness: Individual 12V batteries are typically less expensive than a single 36V battery. This can be an attractive option if you already have 12V batteries on hand.

  2. Availability: 12V batteries are more readily available and come in a wide variety of brands, chemistries, and price points.

  3. Modular Replacement: If one battery fails, you can replace it individually rather than replacing an entire 36V unit.

  4. Flexibility: The modular nature of 12V batteries allows for easier transport, installation, and swapping.

Downsides

  1. Weight and Space: A three-battery setup is significantly heavier and takes up more space compared to a single 36V battery. This can be a concern for smaller boats with limited storage or weight capacity.

  2. Maintenance: You’ll need to monitor and maintain three separate batteries. Ensuring that all batteries are balanced and equally charged can be time-consuming.

  3. Complex Wiring: Connecting three batteries in series requires additional wiring, which adds complexity to the setup and increases the potential for wiring issues.

Single 36V Battery Setup

How It Works

A single 36V lithium battery delivers the full voltage required for the trolling motor, eliminating the need for multiple batteries in series.

Benefits

  1. Compact and Lightweight: A single 36V battery is much smaller and lighter than a 3-battery system, freeing up valuable space and reducing weight in your boat.

  2. Simplified Wiring: With only one battery to connect, installation is straightforward and reduces the likelihood of wiring issues.

  3. High Performance: Most 36V lithium batteries are designed specifically for trolling motors, offering consistent voltage output and longer run times.

  4. Ease of Use: There’s no need to balance or maintain multiple batteries. A single unit simplifies charging and overall upkeep.

Downsides

  1. Higher Initial Cost: 36V lithium batteries are a significant upfront investment. However, their longer lifespan and performance can offset this cost over time.

  2. Replacement Cost: If the battery fails, replacing a single 36V unit is more expensive than replacing one 12V battery in a series.

  3. Limited Availability: High-quality 36V lithium batteries may not be as readily available as 12V batteries, depending on your location or retailer.

Performance Comparison

Weight and Space

  • Three 12V Batteries: Heavier and bulkier; requires careful planning for installation.

  • Single 36V Battery: Compact and lightweight; ideal for boats with limited space.

Ease of Maintenance

  • Three 12V Batteries: Requires monitoring and balancing; more connections to check and maintain.

  • Single 36V Battery: Minimal maintenance with a single unit to manage.

Cost Over Time

  • Three 12V Batteries: Lower upfront cost but may require more frequent replacements and additional wiring components.

  • Single 36V Battery: Higher upfront cost but potentially lower long-term costs due to durability and extended lifespan.

Reliability

  • Three 12V Batteries: If one battery fails, performance drops significantly, and troubleshooting is required.

  • Single 36V Battery: Consistent performance, but a failure results in the need for a complete replacement.

Which Setup Is Right for You?

The choice between a three 12V battery setup and a single 36V battery depends on your specific needs and priorities:

  • Choose Three 12V Batteries If:

    • You’re on a budget and want a cost-effective solution.

    • You prefer modularity and the ability to replace individual components.

    • Weight and space are not significant concerns.

  • Choose a Single 36V Battery If:

    • You prioritize simplicity, efficiency, and reduced maintenance.

    • You want to minimize weight and maximize storage space.

    • You’re willing to invest upfront for better long-term performance.

Conclusion

Both setups have their unique advantages and trade-offs. A three 12V battery system offers cost-effectiveness and flexibility, while a single 36V lithium battery provides simplicity and superior performance. Consider your boat’s size, storage capacity, and how much you’re willing to invest upfront to make the best choice for your trolling motor needs.