Best Lithium Batteries for Trolling Motors (12V/24V/36V)

Quick answer: Match the battery voltage to your trolling motor: 12 V for small motors up to about 55 lb thrust, 24 V for 55–80 lb, and 36 V for high-thrust motors above 80 lb. Choose LiFePO4, which gives close to 100% usable capacity at roughly half the weight of lead-acid, and size amp-hours from the motor’s amp draw times the hours you run it. A 36 V 100 Ah LiFePO4 bank typically runs a high-thrust motor all day where an equivalent lead-acid bank would not.

Key facts

• Voltage vs thrust: 12 V ≤55 lb, 24 V 55–80 lb, 36 V >80 lb.
• Usable capacity: ~100% (LiFePO4) vs ~50% (lead-acid/AGM).
• Weight saving: roughly half or better — better hole-shot and less bow weight.
• Runtime is set by amp-hours ÷ motor amp draw; higher voltage uses fewer amps for the same thrust.
• Wiring: batteries in series add voltage, in parallel add amp-hours.
• Cycle life: 2,000–5,000 (LiFePO4) vs 300–500 (AGM).

Why lithium for a trolling motor?

Trolling motors run at high current for hours, then sit idle for days — a duty cycle that destroys lead-acid. LiFePO4 holds voltage flat all day, so the motor keeps its speed on the last cast instead of fading as the bank sags. It is also roughly half the weight, which matters on a boat where every pound of bow weight changes how the hull runs.

Which voltage do I need: 12 V, 24 V, or 36 V?

Higher voltage does not make a motor more powerful by itself — the motor is built for a specific voltage. Choose the voltage your motor is rated for, then size the amp-hours for the runtime you need.

How do I calculate runtime?

Divide the usable amp-hours by the motor’s amp draw at your chosen speed. For example, a motor drawing 30 A at cruising speed on a 36 V 100 Ah LiFePO4 bank gives roughly three hours at that setting. Because LiFePO4 provides close to 100% usable capacity and holds voltage flat, you can use almost the whole rating — where a lead-acid bank would fall off after about half.

Series vs parallel wiring rules

Batteries in series add voltage (two 12 V in series = 24 V); batteries in parallel add amp-hours (two 100 Ah in parallel = 200 Ah). Never mix voltages or chemistries in one bank, and always use batteries of the same model and age when wiring in parallel so they share the load evenly. A single higher-voltage LiFePO4 pack is usually simpler than a series string.

BMS and safety specs that matter

The BMS is the real brains of a lithium trolling battery. Look for over-current, over- and under-voltage, short-circuit, and temperature protection, plus active cell balancing. For wet, exposed installations choose an IP-rated case and sealed connectors. A quality BMS is also what allows the battery to be charged quickly between trips without risk.

Charging between trips

LiFePO4 charges far faster than lead-acid, so an overnight charge is usually enough. Use a charger with a LiFePO4 profile — a lead-acid profile will not fill the battery fully and can shorten its life. Multi-bank chargers handle a 24 V or 36 V series string cleanly, and a dedicated trolling motor batteries charger matches the pack.

Cost and lifespan

Lithium costs more upfront, but a trolling battery that lasts 2,000–5,000 cycles instead of 300–500 pays for itself quickly for anyone who fishes often. Add the weight saved and the flat voltage, and the upgrade is one of the highest-impact changes you can make to a boat.

CMX Battery supplies trolling motor batteries at 12 V, 24 V, and 36 V, plus marine LiFePO4 batteries and custom battery packs for boats with unusual tray or wiring layouts.

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• RV lithium battery guide
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