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Trolling motor and electric boat questions, answered

The questions anglers ask on The Hull Truth, BassResource, Walleye Central and In-Depth Outdoors, answered from Minn Kota's manual and the battery and outboard makers' own specs. Run times are our arithmetic from those figures.

Updated . Every answer lists the sources we read it from. If we couldn't back an answer, we left the question out.

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How long will a trolling motor battery last?

Safety first. Protect the motor leads with the circuit breaker or fuse the motor maker specifies (Minn Kota lists a 60 A breaker for its 50 to 55 lb, 12-volt motors) and the wire size its manual gives for your cable length. Keep the terminals tight and covered.
Hours on a 100Ah battery, Minn Kota maximum draw
MotorMax drawLithium, full speedLithium, half speedAGM, half speed
30 lb, 12 V30 A3.3 h6.7 h3.3 h
45 lb, 12 V42 A2.4 h4.8 h2.4 h
55 lb, 12 V50 A2.0 h4.0 h2.0 h

Half speed uses half the maximum draw, Newport's rule of thumb. Wind, current and a heavy boat raise the draw; slow trolling lowers it. Renogy advises not running its AGM below 50%.

Worked example

A 55 lb Minn Kota draws up to 50 amps. 100 usable amp-hours ÷ 50 amps = about 2.0 hours at full speed. At half speed, about 4.0 hours.

Source: Minn Kota Endura C2 owner's manual (PDF) · Trolling motor runtime calculator

Run your own numbers: Runtime calculator for your motor · Best trolling motor batteries

Sources

What size battery do I need for my trolling motor?

Safety first. Wire batteries in series only with identical batteries of the same type, age and charge, keep every terminal tight and covered, and protect the motor leads with the breaker or fuse the motor maker specifies.

Connecting batteries in series raises the voltage; connecting them in parallel raises the capacity (Victron, Wiring Unlimited).

Redodo says its 12V 100Ah gives the same usable energy as a 200Ah lead-acid battery, because it is rated for full discharge while Renogy advises not taking its AGM below 50%. Use the runtime calculator to check a battery against your motor and speed.

Worked example

For 6 hours at about half speed on a 55 lb motor (about 25 amps): 25 × 6 = 150 amp-hours used. A 100Ah lithium covers that; an AGM, at about 50 usable amp-hours per 100Ah, needs about 3 batteries in parallel.

Source: Minn Kota Endura C2 owner's manual (PDF) · Trolling motor runtime calculator

Run your own numbers: Trolling motor battery picks · 24V vs 36V trolling motors

Sources

Can I charge a lithium trolling battery with a regular charger?

Safety first. Never use a lead-acid charger's equalize, desulfate or repair mode on a lithium battery; those modes push the voltage too high. Don't charge a LiFePO4 battery below freezing (32 F) unless its maker says it has low-temperature charge protection or a built-in heater.

Our boat charging guide covers onboard chargers, alternators and solar for 12, 24 and 36-volt setups.

Worked example

A Redodo 12V 100Ah on a 20-amp LiFePO4 charger: 100 amp-hours ÷ 20 amps = about 5 hours from empty, which is the figure Redodo gives.

Source: Redodo 12V 100Ah LiFePO4 battery, product page · Trolling motor runtime calculator

Run your own numbers: Charging lithium on a boat

Sources

Is lithium worth it over AGM for a trolling motor?

Per usable amp-hour that is about $2.70 for the lithium and $4.18 for the AGM. Redodo backs its battery with a 5-year warranty.

Worked example

Price per usable amp-hour on October 25, 2026: Redodo lithium $269.99 ÷ 100 = $2.70; Renogy AGM $208.99 ÷ 50 = $4.18.

Source: Renogy Deep Cycle AGM Battery 12V 100Ah, product page · Lithium vs AGM calculator

Run your own numbers: Lithium vs AGM calculator

Sources

Are electric outboards worth it, and how far can they go?

ePropulsion's own run-time table for the Spirit shows how much speed costs: about 35 miles in 10 hours at 3.5 mph, 22 miles at 4.4 mph, and under 8 miles in 1.25 hours at full power (6.2 mph). Charging the Spirit's battery from empty costs about $0.23 at the US average price (EIA, July 2026).

Our outboard guide compares Torqeedo, ePropulsion and Mercury models on price, range and running cost.

Worked example

22 miles at a steady 4.5 mph is about 4.9 hours on the Spirit 1.0's 1,276 Wh battery. Recharging 1.3 kWh at 18.2 cents per kWh costs about $0.23.

Source: ePropulsion Spirit 1.0, product page · Electric outboard running cost

Run your own numbers: Electric outboard guide · Wiring a boat's house battery (CamperVolts) (opens in a new tab)

Sources

More questions answered

Keep going

Estimates only. Your actual costs depend on your utility's rate plan, how and when you charge or use power, and local prices. This is general information, not electrical, financial, tax or legal advice. Safety first: follow each maker's instructions and your local codes, use certified equipment, and have a licensed professional do any wiring. See our safety notes and disclaimer.