Re: Trolling motor to fast in slowest speed
I had the same problem with my canoe, the lowest setting was too fast for holding position, etc. Lowering the voltage isn't a good solution, it will likely lead to overheating the motor windings.<br /><br />So I built a maximizer control just like they outfit the better motors with. It's quite simple actually. A PWM circuit with a power device to drive the motor. I have a 10 turn potentiometer to set the speed and it works on all the discrete settings of the motor. I used an IGBT to supply the motor but you could use several different approaches.<br /><br />The simplest approach for the PWM is to use a 556 timer chip to provide the pulse modulation. Use the first timer to produce a clock of around 1.5 kHz. Feed that into the second timer to vary the duty cycle from 10% to 100%.<br /><br />I used a 14538 dual monostable since I had them on hand but the approach is the same.<br /><br />I added a switch to quickly change between the maximizer and the normal battery supply so you don't have to change the maximizer setting when you want to go full speed over to the next spot.<br /><br />Cost in parts is about $20 and about two hours to build. Works great!
