A standard 24V trolling motor typically draws between 5A and 60A of current. High-power motors like the Minn Kota Ultrex Quest 90/115 can draw up to 70A. The greater the thrust, the more power is required.
However, it is important to note that the current draw of a 24V trolling motor cannot be determined by a rough estimate alone; the specific value must take into account factors such as thrust, speed settings, boat weight, water current conditions, and motor efficiency.
The details are provided below.
How much current does a typical 24V trolling motor consume?
The maximum operating current range for most 24V trolling motors is approximately as follows:
| Thrust Rating | Maximum Current Draw Range |
|---|---|
| 24V 70 lb | 40A–45A |
| 24V 80 lb | 50A–56A |
| 24V 100 lb | 55A–65A |
| 24V 112 lb | 60A–70A |
The maximum current range listed in the table refers to the peak current of the trolling motor at its highest speed.
The difference in current varies significantly at different speeds
The current drawn by a trolling motor increases rapidly as speed increases.
Take a 24V, 80-pound trolling motor as an example:
| Speed Setting | Current Draw |
|---|---|
| Low-Speed Cruising | 10A–20A |
| Medium-Speed Operation | 25A–35A |
| High-Speed Propulsion | 40A–50A |
| Full-Speed Thrust | 50A–56A |
Under normal driving conditions, the current drawn by a motor rated at 50A is typically only 15A to 30A, so the full 100Ah capacity is not utilized.
The greater the thrust, the higher the current
As we know, thrust is one of the factors that affect output power. The higher the thrust, the greater the torque output of the motor, and the greater the power required.
The relationship between power, voltage, and current can be expressed by the formula: P = V × I.
Therefore, the higher the power, the greater the current will necessarily be.
The following is a reference table:
| Power Output | Current Draw in a 24V System |
|---|---|
| 240W | 10A |
| 480W | 20A |
| 720W | 30A |
| 1200W | 50A |
The weight of the vessel affects the current
The current requirements for the same trolling motor vary significantly depending on the type of boat: on small aluminum boats, which have low drag and are lightweight, the power requirements are minimal, and 15–25 A is sufficient for normal operation.
In contrast, large fiberglass boats have heavier hulls and correspondingly higher drag, requiring greater thrust; approximately 40–55 A is needed for normal operation.
| Boat Type | Boat Weight | Water Resistance | Current Draw (24V System) | Usage Scenario |
|---|---|---|---|---|
| Small Kayak / Inflatable Boat | Very Light | Very Low | 5A–15A | Small lakes, calm water, short-distance fishing |
| Small Aluminum Boat | Light | Low | 15A–25A | Freshwater fishing, slow cruising |
| Medium Aluminum Fishing Boat | Medium | Moderate | 20A–35A | Daily trolling, moderate wind and current |
| Small Fiberglass Bass Boat | Medium-Heavy | Moderate-High | 25A–40A | Bass fishing, higher-speed positioning |
| Large Fiberglass Bass Boat | Heavy | High | 35A–50A | Spot-Lock, strong current, long-distance trolling |
| Pontoon Boat | Very Heavy | Very High | 40A–55A | Multi-passenger use, windy lakes, continuous propulsion |
| Large Offshore Fishing Boat (24V Setup) | Extremely Heavy | Extremely High | 45A–56A | Coastal fishing, rough water, heavy-duty positioning |
Wind, waves, and currents can increase power consumption
Sailing on a calm lake uses far less power than sailing on a rough sea.
| Water & Weather Conditions | Current Draw (24V System) |
|---|---|
| Calm Lake / No Wind | 10A–20A |
| Light Wind / Mild Current | 20A–30A |
| Moderate Wind & Waves | 30A–40A |
| Strong Headwind / Strong Current | 40A–50A |
| Heavy Waves / Continuous High-Speed Operation | 50A–56A |
| High-Thrust 24V Models Under Extreme Load | Up to 60A+ |
PWM speed control systems are more energy-efficient
Even among 24V trolling motors, power consumption during low-speed operation varies depending on the speed control method.
Traditional resistance-based or gear-based speed control works as follows: the battery supplies a certain amount of power, but the motor uses only a portion of it; the remaining power is converted into heat through resistors or coils, resulting in waste. Therefore, even though the boat moves slowly during low-speed operation, battery power consumption does not decrease significantly.
PWM speed control technology, however, operates differently. Instead of constantly running at "half-power" and wasting energy, it controls speed by rapidly switching the current in pulses. For example, if the average current consumption during low-speed operation is 30%, PWM can limit current consumption to 30%, thereby conserving more battery power.
It is important to note that while PWM speed control technology effectively extends battery life during low- and medium-speed operation, the motor still consumes a significant amount of current when operating at full speed.
What are the battery requirements for a 24V trolling motor?
When considering a battery for a 24V trolling motor, do you usually check the capacity first?
In fact, you should also pay attention to the battery's continuous discharge capacity.
For a trolling motor with a maximum current of 56A, you should use a battery with a continuous discharge current of 60A or even 80–100A.
If the battery's continuous discharge current is lower than the trolling motor's maximum discharge current, the motor may suddenly shut off during high-speed operation because the overcurrent protection in the lithium-ion battery's management system has been triggered.
Why is there such a big difference in battery life among 100Ah batteries?
100Ah simply indicates how much energy the battery can store, but it does not guarantee that it can deliver a stable current in an application such as a trolling motor. For example, two batteries both labeled as 24V 100Ah would, in theory, have a total capacity of approximately 2.56 kWh.
However, unlike a small light bulb, a trolling motor requires a current draw of over 50A during high-speed operation.
If a standard lithium battery can only sustain a continuous discharge of 50A, it is already operating near its limit under these conditions. Continued use will cause the battery voltage to drop and the Battery Management System to overheat, triggering the BMS's overcurrent protection and causing the boat to lose power suddenly.
The advantage of LiFePO4 batteries lies in the fact that they not only have a capacity of 100Ah but can also deliver high currents more stably.
For example, the CoPow 24V 100Ah trolling motor battery has a continuous discharge capacity of over 100A. Even after running at full speed for a period of time, the battery voltage will not fluctuate significantly, and there will be no sudden power loss due to BMS overcurrent protection, which could cause the boat to come to a halt.
How do you calculate the runtime of a 24V trolling motor using a formula?
The calculation formula is as follows:
Runtime (hours) = Battery Capacity (Ah) ÷ Current Draw (A)
For example, for a 24V, 100Ah battery with a continuous discharge current of 25A, its theoretical runtime can be calculated using the following formula: 100 ÷ 25 = 4 hours.
Related articles: How Long Will a 24V 100Ah Battery Last with a Trolling Motor?
