[PSUBS-MAILIST] question

Tue Oct 7 09:08:33 EDT 2025

Rick, these Minn Kota trolling motors are simple brushed DCmotors.  Let’s assume you are using a 36V trolling motor and a Minn- Kotamotor controller.     If you completely disconnect the motorcontroller from the motor, then if you connected the motor to a 36V bank, thenthe motor will run full speed in one direction.  If you reverse thepolarity to the motor , it will run full speed in the opposite direction.   Because you note that when you energize the potentiometer, the motorcomes on full speed in one direction, this means that motor controller issupplying either a 5V signal or 0V signal to the motor.  These Minn-Kotamotor controllers have two connections for the battery bank and two connectionsfor the motor.  They also have three conductors for the potentiometer. One of the connections is a regulated 5V power supply, one is the ground andthe third goes to the swiper leg of the potentiometer.  This swiper leg isan input to the motor controller.  If you supply 5V to this swiper leg,then the motor will run full speed in one direction, if you supply 0V to thisswiper connection, then the motor will run full speed in the opposite directionand if you supply 2.5V to this swiper connection to the motor controller, thenthe motor will be off.  So, either the motor controller is faulty or the potentiometeris faulty assuming you have connected the potentiometer correctly to the motorcontroller.  Since your motor is coming on when you energize the potentiometer,you know the 5V power supply from the motor controller is working.   You can trouble shoot the potentiometer by connecting the multimeter probes tothe outer legs of the three leg potentiometer and energizing the potentiometer. The motor will come on and the multimeter will either read 5V or -5V. From this, you can deduce which is ground and which is the 5V powersupply.  Next connect the ground probe of multimeter to the ground leg ofthe potentiometer and connect the multimeter positive probe to the swiper ormiddle leg of the potentiometer.  Energize the potentiometer and rotatethe potentiometer.  If the potentiometer is working, the voltage willrange from 0-5V and the motor will go from full one direction to full the otherdirection and stop when the multimeter is near 2.5V.  If from this testyou do not see the variation of voltage from 0-5V, then the potentiometer isbad.  If you  do see the swiper leg voltage move from 0-5V when youturn it and the motor is not changing, then you have a bad motorcontroller.   I have had these motor controller go bad in thepast.  Hope this helps.
Cliff

    On Monday, October 6, 2025 at 08:14:24 PM CDT, Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

 Hi Alan, couple of questions,, I don't understand what you mean by "Changing the red and black? when you say "put the probe on the side one and middle one and should get 5V, what position should the potentiometer be in? neutral or full ahead or astearn? also, when I energise the potentiometer, the motor just goes full tilt in one direction so I assume it has to be energised to look for that reading?
Rick

On Mon, Sep 29, 2025 at 12:35 PM Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Rick, you can just try out the wires in different positions, you won't do any damage.Normally you have a black & a red wire & they go on the far left & far right pin, and a coloured wire goes on the middle pin. Start with the coloured wire in the middle first & change the red and black.If that fails you can check that the potentiometer is working with a multi meter.If you put the probe of the meter on one of the outside pins & the other probe on the middle pin, you should see the voltage vary from 0 to 5V. Or sometimes 0-3.5V.You could look inside the black box & see if the wires have come off in there.All the best.Alan

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  On Tue, 30 Sept 2025 at 11:23 am, Rick Patton via Personal_Submersibles<personal_submersibles at psubs.org> wrote:   _______________________________________________
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