Trolling motor with homemade speed control (Maximizer)

In this video I show you the effect of a digital controller on the power consumption of a trolling motor. Sometimes it's called a maximizer (Minn Kota Maxxum or Traxxis) or digital motor (MotorGuide).
I have a 56lbs motor with 5 forward and 3 reverse speeds. The speed is regulated by speed coils (resistors) in the motor. They produce a lot of heat and thus waste precious battery energy.
I decided to build my own digital regulator and the result is as expected: run time doubles. No modification are needed for the motor, just put it in the fastest setting (5).

How long can I run on a 105AH semi traction battery?
Note that battery capacity is often given in 20H discharge rate. At a 5 or 3 hour rate the capacity drops a lot unless you buy a more expensive traction type battery. Better look for 5H capacity for a trolling motor.

Example:
Motor draws 20A using speed coils (setting 3):
The battery supplies 20A. The battery capacity drops from 105AH to 61AH. You can use it 3 hours at most.

Motor draws 20A using digital regulator (motor at setting 5):
The battery supplies 12A. The battery capacity drops from 105AH to 75AH. You can use it 6 hour and 15 minutes at most.

But never discharge your battery this deep. Try to use at most 50% and your battery will last much longer.

For those interested in the details of this project, you can download a zip with everything in it frome here:
https://www.dropbox.com/s/0bvkebsha5n7lrv/motor_control_v1.4.zip?dl=1

Видео Trolling motor with homemade speed control (Maximizer) канала Theo B