Trolling Motor Batteries – The Complete Guide

A trolling motor is only as good as the battery powering it. Choosing the right trolling motor battery ensures longer runtime, consistent performance and reliable power while on the water. This complete guide will help you understand battery sizes, the difference between marine starting and deep cycle batteries, and how to maximize your trolling motor’s performance.

Common Trolling Motor Battery Group Sizes & Capacities

Choosing the correct battery group size is crucial for efficient trolling motor performance:

Group 24: 70–85 Ah – Ideal for light-duty applications or small boats.
Group 27: 90–100 Ah – Offers moderate runtime and power for most recreational boats.
Group 31: 100–125 Ah – Heavy-duty, high-power demand; perfect for anglers spending long hours trolling.

Pro Tip: A Group 31 deep cycle battery is recommended for extended trips and consistent performance.

What Size Battery Do You Need for Your Trolling Motor?

Battery size depends on your boat’s voltage system and motor thrust rating:

12V System (up to 55 lbs thrust): Requires one 12V battery
- Good: 24DC with 75-85Ah
- Better: 27DC with 90-100Ah
- Best: 31DC with 100-120Ah
24V System (up to 80 lbs thrust): Requires two 12V batteries in series
- Good: 27DC with 90-100Ah
- Best: 31DC with 100-120Ah
36V System (up to 120+ lbs thrust): Requires three 12V batteries in series
- Best: 31DC with 100-120Ah

Choosing the right capacity ensures longer run time, more consistent voltage, and prevents early battery wear.

Why Battery Capacity Matters

Trolling motors draw steady power over long periods. Using a battery that is too small can:

Drain quickly and leave you stranded
Lose voltage under load
Shorten battery lifespan

Tip: More amp-hours (Ah) equals longer runtime and reliable performance on the water.

AGM vs Flooded Trolling Motor Batteries

AGM Batteries

Maintenance-free and spill-proof
25x better vibration resistance
Longer lifespan: up to 1,200 cycles at 50% depth of discharge
Lower cost per usage

Flooded Batteries

Lower upfront cost
Require regular maintenance
Must be installed upright
Higher cost per usage

For most anglers, AGM batteries offer superior reliability and convenience.

How Long Will a Trolling Motor Battery Last?

Battery run time depends on multiple factors:

Amp-hour (Ah) rating
Motor thrust and speed
Wind and water conditions
Weight of the vessel

Tip: For full-day trips, always choose a higher-capacity battery to ensure consistent power.

Need Help Choosing the Right Trolling Motor Battery?

If you’re unsure which battery suits your boat, our experts can guide you based on:

Motor thrust rating
Boat size
Typical usage patterns
Available battery space

Visit us in-store or contact us today for personalized advice.

Frequently Asked Questions (FAQs)

Can I use a starting battery for a trolling motor?

No. Starting batteries are designed for short, high-current bursts to start engines. Using them for trolling motors will drain the battery quickly. A deep cycle or marine battery is the best choice.

How long will a 100Ah trolling motor battery last?

Runtime varies by motor thrust, speed and water conditions. Generally, a 100Ah deep cycle battery can power a moderate trolling motor for 4–8 hours.

Should I choose AGM or flooded batteries for my trolling motor?

AGM batteries are preferred due to maintenance-free design, spill-proof construction, and vibration resistance. Flooded batteries are cheaper but require care and upright positioning.