tramcar trev said:
Maybe back emf is the cause as they seem to reset if the power is turned off.... C'mon give us a clue as to type and size of capacitor and I'll try it too...
If I put a large cap across the motor that is going to provide some inertia so stops will be more gradual and starts would be "softer" so a smaller cap would kill off any rf I would assume... But this is beyond me.... Makes sense though.... but someone on the forum would be able to calculate exactly the size of the capacitor needed...
I've been suspecting back emf all through this discussion. To stop back emf, you could try some of the options in this sketch - no guarantees! I'm assuming the led controller has a PWM type output.
[style="color: #ff6600;"]IMPORTANT - CIRCUIT GOES BEFORE REVERSING RELAY CONTACTS to keep polarity correct.
Try D1 first - it might 'mimic' the usual feeding into leds. To do the testing, you could use any 1A rated diode, but for a final setup, use something bigger to match the current draw of the motor.
If no help, try D2 as well. It can be 1A rated.
C1 - you can start with 0.1 uF and go up to 4700 uF if you want. Depending on the frequency of the led controller, you will find the max size that still allows you speed control. Too big and it will appear as full on all the time.
There's no way you can use a big capacitor to give a 'soft stop' feature when using PWM type control (as the led controller probably is) The cap just charges up to the peak voltage and the power is full on all the time. It has to be small enough to allow it to completely discharge into the motor during the PWM off time.
I also suspect that when you get to test it with power supplied through the rails and not a battery, the bad contact between rail and wheel may cause problems with the led controller. How have you done your testing so far? battery? solid connection to power supply?