Trolling motors run on 12, 24 or 36 volts. The voltage is set by the motor, and you reach it by connecting 12-volt deep-cycle batteries together.
How many batteries do you need?
- 12-volt motor: one 12V battery.
- 24-volt motor: two 12V batteries wired in series (positive of one to negative of the other).
- 36-volt motor: three 12V batteries wired in series.
Wiring in series adds the voltage while the amp-hour capacity stays that of a single battery. As a rule, 55 lb thrust motors are 12V, 70-80 lb motors 24V and 112 lb motors 36V. Check your motor’s specification.
Choosing the batteries
- Use deep-cycle batteries, not engine starting batteries; trolling draws steady current for hours.
- Use batteries of the same type, age and capacity in one bank.
- Higher amp-hour capacity gives longer run time; lithium (LiFePO4) batteries are much lighter than lead-acid for the same capacity.
- Use an on-board charger with one bank per battery so each battery charges fully.
- Fit a circuit breaker of the size your motor’s manual specifies.
Lithium trolling motor batteries
Lithium iron phosphate (LiFePO4) batteries weigh much less than lead-acid batteries of the same capacity, and they let you use more of their rated capacity. Charge them with a charger designed for lithium, and if you plan to connect several in series for a 24V or 36V motor, first confirm the battery maker allows it and follow its limits. How many seasons to expect: how long do lithium batteries last?
Lead-acid, AGM or lithium?
| Flooded lead-acid | AGM | Lithium (LiFePO4) | |
|---|---|---|---|
| Upfront cost | Lowest | Medium | Highest |
| Weight | Heaviest | Heavy | Much lighter |
| Maintenance | Check water levels | Sealed | Sealed, with a battery management system |
| Usable capacity | Lifespan suffers if regularly discharged deeply | Similar to lead-acid | Most of the rated capacity |
| Charger | Standard | AGM setting | Lithium profile |
How long will a battery run my trolling motor?
A rough estimate is the battery’s amp-hour rating divided by the motor’s current draw: at about 20 amps, a 100Ah battery would in theory run for about five hours. Real run time is shorter, because motors draw much more at high speed, wind and current raise the load, and lead-acid batteries should not be run flat. Running at lower speed settings stretches run time considerably. In a 24V or 36V series bank the amp-hour capacity stays that of one battery, while the motor’s draw is spread across the higher voltage.
Charging
Use an onboard charger with one bank per battery, or the charger the battery maker specifies for lithium. The LBP lithium bundles we carry, for example, include an onboard charger, a 10-amp charger with the 36V 60Ah pack and a 15-amp charger with the 12V 100Ah pack, and LBP quotes roughly 4 to 6 hours for a full recharge from empty.
Lithium trolling motor batteries in stock
- LBP Lithium Battery Bundles: $970.00
- Ionic Lithium 12V 300Ah LiFePO4 Deep Cycle Battery with Bluetooth and Heater: $1,599.00
See also: what size trolling motor do I need · how to wire a 24 volt trolling motor · all trolling motors.
Related guides: winter battery storage.
More guides: trolling motor troubleshooting · how to charge trolling motor batteries · how long a battery lasts · deep cycle vs starting battery · marine battery vs car battery · 12V vs 24V vs 36V trolling motors.
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