🔋 Which Battery Should I Choose for an Electric Trolling Motor?
Choosing the right battery is more important than many people realize when using an electric motor on a boat.
The wrong battery can result in:
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short operating time
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poor thrust
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voltage drop
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unnecessary wear on the system
Here is what you should look for to ensure a setup that works reliably in practice.
⚡ Electric Motors Require High and Stable Current
An electric motor can draw a significant amount of current — especially under heavy load.
That is why it is important to choose a battery that:
✔ can deliver high current
✔ maintains stable voltage
✔ handles many charge cycles
Otherwise the motor will quickly lose efficiency.
🔋 AGM or Lithium – Which Is Better?
Both types can be used, but they behave differently.
AGM battery
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lower purchase price
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heavier
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less usable capacity
Lithium (LiFePO4)
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lower weight
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more usable capacity
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stable voltage under load
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longer service life
For these reasons, many boat owners choose lithium batteries for electric motors.
See lithium batteries here:
https://sejlstroem.dk/collections/lithium-batteri-lifepo4
⚡ 12V, 24V or 48V?
System voltage plays a major role.
12V → small electric motors and shorter runtime
24V → more efficient operation and reduced cable losses
48V → larger systems with higher power output
The higher the voltage, the lower the current required for the same power — which means smaller cables and fewer losses.
🔌 Cables Matter More Than Many People Think
Even the best battery will not help if the cables are undersized.
Cables that are too small can cause:
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voltage drop
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overheating
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reduced motor performance
You can calculate the correct cable size here:
https://sejlstroem.dk/pages/kabelberegner
🧮 What Battery Size Should You Choose?
This depends on:
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the motor’s power consumption
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how long you want to run the motor
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speed and load conditions
As a rule of thumb:
✔ larger battery = longer runtime
✔ lithium provides the most usable energy per kilogram
❓ Frequently Asked Questions
Can I use a standard leisure battery?
Yes, but it often results in shorter runtime and lower performance.
Is lithium better for electric motors?
Yes, most users experience longer runtime and more stable power.
Why does my motor lose power?
This is often caused by low voltage or cables that are too small.
🤔 Unsure Which Battery to Choose?
If you are unsure what fits your electric motor, feel free to include:
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motor size
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system voltage (12 / 24 / 48V)
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desired runtime
This makes it much easier to find the right solution.
⭐ Why the Right Battery Matters
✔ longer runtime
✔ better thrust
✔ less voltage drop
✔ more stable operation