Complete Guide: Battery for Trolling Motor: Best 12V, 24V and 36V Options
The best battery for trolling motor use is a deep cycle with enough amp-hours to last your fishing day. For motors under 55 lbs thrust, a single Group 27 deep cycle (100Ah) runs 5-6 hours at half throttle. Higher-thrust motors or 24V/36V setups need multiple batteries wired in series. Lithium batteries cost 3-4x more but last 5-10x longer and weigh half as much.
This guide covers everything about choosing a battery for trolling motor applications. We’ll compare lithium vs lead acid, explain 12V/24V/36V setups and help you calculate runtime. For charging, see our marine battery charger guide. No fluff, just what you need to stay on the water all day.
Best Battery for Trolling Motor: The Basics
Trolling motors need deep cycle batteries. That’s the non-negotiable starting point.
A deep cycle battery is built to discharge slowly over hours, then recharge and do it again. Compare that to a starting battery which dumps a ton of amps for a few seconds to crank an engine. Use a starting battery on a trolling motor and you’ll kill it within a season.
Deep Cycle vs Starting vs Dual Purpose
Deep cycle batteries have thicker plates that handle repeated discharge cycles without warping. They’re rated in amp-hours (Ah), which tells you total capacity. A 100Ah battery can deliver 5 amps for 20 hours or 50 amps for 2 hours.
Starting batteries have thin plates with lots of surface area for quick high-amp bursts. Great for engines, terrible for trolling motors. The thin plates can’t handle deep discharges.
Dual purpose batteries try to do both. They work okay as a backup but don’t excel at either job. If you have room for separate batteries, go dedicated.
Lithium vs Lead Acid for Trolling Motors
You’ve got three main choices for trolling motor batteries:
Flooded lead acid (FLA): The cheap option. Requires maintenance—you need to check water levels and keep terminals clean. Sensitive to position (can spill if tipped). Lasts 2-4 years with proper care. Figure $100-150 for a quality Group 27.
AGM (Absorbed Glass Mat): Sealed, maintenance-free and spill-proof. Handles vibration better than flooded. Costs more upfront ($200-300) but lasts longer and charges faster. Good middle ground for most anglers.
Lithium (LiFePO4): Half the weight of lead acid with 3-4x the cycle life. Holds voltage steady until nearly empty so your motor runs strong all day. Downside is cost—expect $800-1200 for a quality 100Ah lithium. Worth it if you’re on the water constantly.
12V Trolling Motor Battery Setup
The simplest setup. One battery powers one motor. Works for motors up to about 55 lbs thrust.
What You Need
- One Group 27 or Group 31 deep cycle battery (100-130Ah)
- Battery box or tray
- 8 AWG or 6 AWG wiring (depending on motor amp draw)
- Inline fuse or circuit breaker rated for your motor
- Battery charger designed for your chemistry type
Wiring a 12V System
Connect the positive terminal on your battery to the positive lead on the trolling motor. Connect the negative terminal to the negative lead. Add an inline fuse or breaker on the positive side, within 7 inches of the battery.
That’s it. Dead simple.
The fuse protects against shorts. If a wire rubs through and grounds out, the fuse blows instead of your wiring catching fire. Size it about 25% higher than your motor’s max draw—a 50-amp motor gets a 60-amp fuse.
12V Runtime Estimates
Your runtime depends on battery capacity and motor draw. Here’s a rough guide for a 100Ah battery:
| Speed Setting | Amp Draw | Runtime |
|---|---|---|
| Low (10%) | 5-8 amps | 12+ hours |
| Medium (50%) | 20-25 amps | 4-5 hours |
| High (80%) | 35-40 amps | 2.5-3 hours |
| Full (100%) | 45-55 amps | 1.5-2 hours |
These numbers assume a healthy fully charged battery at room temperature. Cold weather cuts capacity by 20-30%.
24V Trolling Motor Battery System
A 24V trolling motor battery setup doubles your power without doubling weight. Two 12V batteries wired in series give you 24 volts while maintaining the same amp-hour rating.
Why go 24V? More thrust. A 24V 80-lb thrust motor moves more water than a 12V 55-lb unit. You get better boat control in wind and current without draining batteries faster.
Wiring Two 12V Batteries in Series for 24V
Series wiring adds voltage while keeping amp-hours the same. Here’s how:
- Connect the negative terminal of Battery 1 to the positive terminal of Battery 2
- The remaining positive (Battery 1) goes to the motor’s positive lead
- The remaining negative (Battery 2) goes to the motor’s negative lead
- Add a fuse or breaker on the positive line from Battery 1
Both batteries must be identical—same brand, same capacity, same age. Mixing old and new batteries causes problems. The weaker battery becomes a bottleneck and wears out even faster.
For more on series vs parallel configurations, check our battery series parallel guide.
24V Battery Recommendations
For 24V systems I recommend two Group 31 AGM batteries in the 100-130Ah range. The VMAXTANKS SLR125 AGM is a solid choice at 125Ah with good cycle life.
If weight matters—and on smaller bass boats it definitely does—lithium makes sense. A pair of 100Ah lithium batteries weighs about 60 lbs total versus 130+ lbs for AGM. That’s 70 lbs off the bow, which changes how your boat handles.
36V Trolling Motor Battery Setup
Tournament anglers and serious fishermen run 36V systems. Three batteries in series deliver maximum thrust for all-day fishing in tough conditions.
Wiring Three Batteries for 36V
Same concept as 24V, just extended:
- Connect Battery 1 negative to Battery 2 positive
- Connect Battery 2 negative to Battery 3 positive
- Battery 1 positive goes to motor positive
- Battery 3 negative goes to motor negative
- Fuse on the positive line from Battery 1
All three batteries must match. When one battery in a series string fails, the whole system suffers. Replace them as a set when capacity drops.
Weight Considerations
Three lead-acid Group 31 batteries weigh close to 200 lbs. That’s a lot of weight on the bow. Lithium cuts that nearly in half, which is why you see most high-end tournament boats running lithium 36V setups.
The weight savings also means more room for gear and a faster boat on plane. If you’re competing and every advantage matters, lithium is the move.
Charging Your Trolling Motor Battery
How you charge matters as much as what battery you buy. Undercharge and you lose capacity over time. Overcharge and you damage the plates.
Charger Types
Single bank chargers charge one battery at a time. Fine for 12V systems or if you don’t mind swapping cables.
Multi-bank chargers charge multiple batteries independently. Essential for 24V and 36V systems. Each bank monitors its battery separately, which prevents overcharging when batteries are mismatched.
On-board chargers mount permanently in your boat and connect to shore power. Plug in at the dock and walk away. The NOCO Genius GEN5X3 is a popular 3-bank option that handles 12V, 24V and 36V systems.
Charging Tips
Charge after every trip. Don’t let batteries sit discharged—sulfation builds up on lead-acid plates and permanently reduces capacity.
Match charger to chemistry. AGM batteries need a lower charge voltage than flooded. Lithium needs a charger with a lithium-specific mode. Wrong settings mean slow charges at best, dead batteries at worst.
Don’t fast charge constantly. Higher amp chargers fill batteries faster but generate more heat. For daily use, a 10-15 amp charger is fine. Save the 40-amp chargers for emergencies.
Check water levels on flooded batteries. Top off with distilled water before charging, not after. Charging causes expansion and can overflow if you fill too high.
How Long Do Trolling Motor Batteries Last?
Battery lifespan depends on how you use and maintain them.
Flooded lead acid: 2-4 years or 200-400 cycles AGM: 4-6 years or 400-600 cycles Lithium LiFePO4: 8-10 years or 2000-5000 cycles
A “cycle” is one discharge and recharge. Going from 100% to 50% and back counts as half a cycle. The deeper you discharge, the fewer total cycles you get.
Signs Your Battery Is Dying
- Won’t hold a charge overnight
- Motor runs slower than it used to
- Battery gets hot while charging
- Voltage drops quickly under load
- Visible swelling or corrosion
When lead-acid batteries start failing, replace the whole series set. One weak battery drags down the others and accelerates their wear.
Trolling Motor Battery Maintenance
A little maintenance goes a long way. Most battery problems come from neglect.
Keep terminals clean. Corrosion adds resistance and reduces power delivery. Scrub with a wire brush and coat with dielectric grease or terminal protector.
Store charged. Never store batteries discharged over winter. Charge them fully, then top off monthly. Freezing temps can crack a discharged battery.
Check connections. Loose connections cause heat buildup and voltage drop. Tighten everything at the start of each season.
Monitor voltage. A healthy 12V battery reads 12.6-12.8V at rest. Below 12.4V means it needs charging. Below 12.0V means it’s been sitting too long or something’s draining it.
For more on battery testing, see our battery tester guide.
Recommended Trolling Motor Batteries
Best Budget: Interstate SRM-27 Marine Deep Cycle
Flooded lead acid, 100Ah. Around $130. Gets the job done for weekend anglers. Needs maintenance but delivers reliable performance.
Best Value: VMAXTANKS SLR125 AGM
125Ah AGM, about $280. Maintenance-free, spill-proof, handles vibration well. Great balance of cost and performance.
Best Lightweight: Ampere Time 12V 100Ah LiFePO4
Lithium iron phosphate, 100Ah at 24 lbs. Costs more upfront but the weight savings and cycle life make it worthwhile for serious anglers.
Best for Tournament Use: Battle Born 100Ah LiFePO4
Premium lithium with 3000+ cycle rating. Built-in BMS, 10-year warranty. The go-to for tournament pros.
Quick Battery Sizing Guide
Not sure what you need? Start here:
| Motor Voltage | Thrust | Recommended Setup |
|---|---|---|
| 12V | 30-55 lbs | 1x Group 27 (100Ah) |
| 24V | 70-80 lbs | 2x Group 27 in series (100Ah) |
| 24V | 80-100 lbs | 2x Group 31 in series (125Ah) |
| 36V | 100-112 lbs | 3x Group 31 in series (125Ah) |
Want more runtime? Go with higher capacity batteries or add a parallel bank. See our series parallel wiring guide for configurations that increase both voltage and capacity.
Related Guides
- Battery Series and Parallel Wiring - How to wire multiple batteries
- Smart Battery Charger Guide - Choosing the right charger
- 12V Battery Analyzer Guide - Testing battery health
- Battery Tester Guide - Load testing your batteries