Guide to Selecting 36V Lithium Batteries for Trolling Motors

Picture yourself on a shimmering lake, steering your boat while enjoying a peaceful fishing session. Suddenly, your trolling motor loses power, forcing you to cut the trip short. This frustrating experience is something every angler wants to avoid. Selecting the proper power source is crucial for seamless water adventures.

For boats equipped with 36V trolling motors, a high-performance 36V lithium battery not only extends fishing time but also significantly reduces weight and eliminates frequent battery changes. With numerous options available, how does one choose the most suitable lithium battery? This article examines capacity selection, configuration options, and practical tips for 36V trolling motor lithium batteries.

When selecting a power source for trolling motors, traditional lead-acid (AGM) and modern lithium (LiFePO4) batteries are the primary options. While both provide power, lithium batteries offer distinct advantages in performance, efficiency, and long-term cost-effectiveness.

• Lead-Acid (AGM): Notably heavy, with a typical 12V 100Ah AGM battery weighing 60-70 pounds. A 36V system requires three batteries, totaling over 180 pounds, affecting boat handling and fuel efficiency.
• Lithium (LiFePO4): 50-70% lighter than lead-acid, with a 12V 100Ah lithium battery weighing just 20-25 pounds. A 36V lithium battery group weighs only 30-60 pounds, improving boat maneuverability and speed.

• Lead-Acid: Voltage gradually drops during discharge, potentially causing power loss before complete depletion, reducing trolling motor efficiency.
• Lithium: Maintains stable voltage until nearly fully discharged, ensuring consistent trolling motor performance throughout use.

• Lead-Acid: Slow charging, requiring 8-12 hours for full capacity, with risk of damage from overcharging.
• Lithium: Fast charging in 2-4 hours with proper charger, safely handling higher currents through built-in Battery Management Systems (BMS).

• Lead-Acid: Typically lasts 300-500 cycles (2-5 years) before significant capacity reduction, increasing long-term replacement costs.
• Lithium: High-quality LiFePO4 batteries provide 4,000+ cycles even with deep discharges, offering superior long-term value.

• Lead-Acid: Lower maintenance but prone to corrosion, requiring regular cleaning and sensitive to overcharging.
• Lithium: Virtually maintenance-free with integrated BMS protection against overcharging, over-discharging, short circuits, and extreme temperatures.

Selecting proper battery capacity requires considering trolling motor power consumption and fishing habits:

1. Check motor amp draw: Consult specifications for maximum amp draw. Many 36V motors with 112lb thrust draw 52-56 amps at full speed.
2. Estimate runtime needs: Multiply amp draw by desired operating hours.

Example calculation for a motor drawing 52 amps at full speed, operating at 25% power for 5 hours:

52 amps × 25% × 5 hours = 65Ah

Most anglers find 50Ah-100Ah capacities sufficient for 36V applications:

• 50Ah: Suitable for occasional short fishing trips with minimal motor use.
• 100Ah: Ideal for extended outings or powering additional onboard electronics.

Anglers debate between connecting three 12V batteries in series versus using a single 36V battery. Each approach has distinct advantages:

Advantages:

• Flexibility for using individual 12V batteries with other electronics
• Easier replacement of single failed units
• Wider availability of 12V chargers and accessories

Considerations:

• Greater weight and bulk
• More complex wiring with potential connection issues
• Longer charging times for multiple batteries

Advantages:

• Simpler installation with single unit
• No series/parallel configuration required
• Lighter weight and compact size

Considerations:

• Requires dedicated 36V charger
• Complete replacement needed if battery fails
• Not compatible with 12V applications

For anglers prioritizing clean installation and space savings, a single 36V lithium battery typically offers the best solution. Those preferring modular setups or already owning 12V batteries may find the three-battery configuration preferable.

Proper battery selection significantly enhances on-water performance and reliability. For occasional anglers, 50Ah batteries suffice, while dedicated fishermen may prefer 100Ah models for all-day power. Single 36V batteries provide simpler installation and maintenance compared to multiple 12V units, though the latter offers greater configuration flexibility.