What Size Deep Cycle Battery for Trolling Motor Should You Use?

Choosing the right deep cycle battery for your trolling motor is essential to ensure optimal performance and longevity. Whether you're out fishing for a day or cruising on a lake, having the right battery size impacts how long your motor runs, how well your boat performs, and ultimately, how much enjoyment you get out of your time on the water.

In this guide, we'll walk you through everything you need to know about selecting the best size deep cycle battery for your trolling motor. We'll cover the essential factors you need to consider, the types of batteries available, how to maintain them, and answer common questions to help you make an informed choice.

Key Factors to Consider When Choosing a Deep Cycle Battery Size

When determining the right size deep cycle battery for your trolling motor, there are a few key factors to consider:

1. Thrust and Power Requirements of Your Trolling Motor

The thrust of your trolling motor (measured in pounds) plays a significant role in determining the size of your battery. Motors with higher thrust require more power and thus larger batteries. For example:

• Motors with up to 55 pounds of thrust: A 12V battery is usually sufficient.
• Motors with 55 to 80 pounds of thrust: You'll need a 24V system, which involves two 12V batteries wired in series.
• Motors with over 80 pounds of thrust: A 36V system (three 12V batteries) is recommended.

Make sure to check the power requirements of your specific trolling motor. Most manufacturers provide guidance on the voltage and amp-hour (Ah) rating you need based on the motor's thrust.

2. Boat Size and Weight

The size and weight of your boat also affect your battery choice. Larger, heavier boats demand more power, which translates to larger or multiple batteries. For smaller boats or kayaks, a single 12V deep cycle battery with around 50-100Ah should be enough. For larger boats with heavier loads, you may need multiple batteries with higher capacity (e.g., 100-125Ah).

3. Battery Voltage: 12V, 24V, or 36V Systems?

Trolling motors come in 12V, 24V, and 36V systems, each requiring a different battery setup:

• 12V motors are common for smaller motors and require one 12V battery.
• 24V motors are typically used for more powerful setups and require two 12V batteries wired in series.
• 36V motors are the most powerful and require three 12V batteries wired in series.

Always ensure that your battery voltage matches the power requirements of your trolling motor to avoid performance issues or potential damage.

4. Battery Group Size

Battery group size refers to the physical dimensions of the battery. The most common group sizes for trolling motors are Group 24, 27, and 31:

• Group 24: Smaller, typically used in light boats or kayaks. They have around 70-85Ah capacity.
• Group 27: Mid-sized batteries with 85-105Ah capacity, suitable for medium to large boats.
• Group 31: The largest commonly used size, offering 100-125Ah capacity for large, heavy boats with powerful motors.

Ensure your boat has enough space to accommodate the group size you choose.

5. Amp-Hour Rating and Battery Capacity

The amp-hour (Ah) rating of a battery indicates how much power it can provide over a specific period. For example, a 100Ah battery can deliver 1 amp of power for 100 hours or 10 amps for 10 hours. When choosing a battery, higher Ah ratings mean longer run times.

Here's a simple formula to calculate run time:

Battery Ah rating÷Motor amp draw=Run time (in hours)

If your motor draws 10 amps and you have a 100Ah battery, the battery will run for approximately 10 hours.

Types of Deep Cycle Batteries for Trolling Motors

There are three main types of deep cycle batteries commonly used in trolling motors:

1. Lead-Acid (Flooded) Batteries

• Pros: Affordable, widely available, and reliable.
• Cons: Heavier, require frequent maintenance, and have shorter lifespans than other types.
• Best for: Occasional boaters or those on a tight budget.

2. AGM (Absorbent Glass Mat) Batteries

• Pros: Maintenance-free, more resistant to vibration, and longer-lasting than lead-acid batteries.
• Cons: More expensive than flooded batteries.
• Best for: Frequent boaters who want a battery with less maintenance and higher durability.

3. Lithium-Ion Batteries

• Pros: Extremely lightweight, longer lifespan (up to 10 years), fast charging, and more environmentally friendly.
• Cons: The most expensive option and may require a specific charger.
• Best for: Serious boaters and anglers who need a long-lasting, high-performance battery for extended trips.

Matching Your Trolling Motor with the Right Battery Size

For Small Boats and Kayaks

For smaller vessels like kayaks or canoes, a single 12V lithium or AGM battery with 50-100Ah should provide ample power. These setups are compact and lightweight, making them easy to transport and install without weighing down your boat.

For Mid-Sized Boats

For mid-sized boats with a 55 lb thrust motor, a 24V system with two 12V batteries (around 70-85Ah each) in series is typically ideal. This setup provides enough power for all-day fishing trips or extended cruising.

For Large Boats and Heavy Loads

For larger boats with high thrust motors (over 80 lbs), a 36V system is recommended. This involves three Group 31 batteries, each offering 100-125Ah. This setup provides maximum run time and power, especially in challenging conditions like strong currents or windy lakes.

Maintaining and Caring for Your Trolling Motor Battery

Proper care is key to maximizing the lifespan of your trolling motor battery. Here are a few tips:

Proper Charging Techniques

Always use the correct charger for your battery type, especially with lithium-ion batteries. Avoid overcharging and undercharging, as this can reduce the battery's lifespan.

Routine Maintenance for Lead-Acid Batteries

For flooded lead-acid batteries, check the water levels regularly and top them off with distilled water as needed. Also, keep the terminals clean and free from corrosion to ensure proper performance.

AGM and Lithium Battery Care

AGM and lithium batteries are low-maintenance, but they still require periodic checks. Make sure the battery is stored in a cool, dry place when not in use.

Storage Tips

During the off-season, store your batteries in a fully charged state in a cool environment. Check the charge periodically to ensure they're ready for your next trip.

Frequently Asked Questions About Battery Size for Trolling Motor

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

A 55 lb thrust motor typically requires a 12V battery with at least 50-100Ah capacity for optimal performance and longer run time.

Can I use a car battery for my trolling motor?

No, car batteries are not designed for deep cycling and can damage your trolling motor. You should always use a deep cycle battery specifically designed for marine applications.

How long will a deep cycle battery last for my trolling motor?

The run time depends on the amp-hour rating of the battery and the power draw of your motor. For example, a 100Ah battery powering a motor that draws 10 amps will last around 10 hours.

What is the best battery type for saltwater use?

Both lithium and AGM batteries are ideal for saltwater use due to their resistance to corrosion. However, be sure to waterproof your battery compartment for added protection.

Conclusion

Choosing the right size deep cycle battery for your trolling motor is critical to ensuring you get the most out of your time on the water. By considering factors such as motor thrust, boat size, voltage requirements, and battery type, you can make a well-informed decision that matches your specific needs.

Remember, larger batteries provide longer run times, but you'll need to balance that with the space available in your boat and your budget. Regular maintenance will keep your battery running efficiently for years to come, ensuring you're always ready for your next adventure.

Whether you're looking for AGM, lithium-ion, or lead-acid batteries, we have the right deep cycle batteries for your trolling motor. Check out our products and find the perfect fit to ensure longer run times and better performance for your boat.