The left hand side diagram shows how our Starter Motor is internally connected, and on the right hand side is how it will be when we have finished modifying it.

And once it is modified it can be connected to a Speed Controller like this.

D1 in this Diagram is there to stop the back EMF from the Field Coils from destroying the MOSFET’s in the Speed Controller. It is best to use a low voltage (<40v) and high current (>5A) rated diode and some heatsinking will be required as it can get quite warm!

Click on the links below for the appropriate section.