The Heinzmann controller board is a very sophisticated system - it’s basic features are: It is a pulse-width controller, with very high efficiency. There is a relay which overrides all the power, and is controlled by moth the on/off switch and a limit switch in the throttle for safety. The controller is specifically designed to prevent “spikes” - common with other controllers, which can damage the motor. The controller is set with a ramp-up period of about 2 seconds - this is for the safety of the rider, and also to protect the motor from excess torque. The ramp-down period of the motor is zero - as soon as the throttle is turned off, then the motor stops. The controller has a number of safety features: It continuously monitors the motor’s temperature, and cuts back on the power to prevent overheating. It also uses this to monitor the average power going to the motor. The controller also uses the “half voltage” from the cells to monitor the battery pack - if just one cell starts behaving erratically, then the controller cuts back to prevent damage to other components. Disabling the pedal sensor: Some Heinzmann systems are supplied with a pedal sensor, which does not let you have any power unitl you pedal. It might be illegal where you are to disable this, but here’s how to do it if you really want to: There are two types of controller board - the older style has an exposed relay, and standard microchips. The new type has a fully enclosed relay, and surface-mount chips. Old type: the pedal sensor electronics are on a separate board, attached by three black wires. Simply snip those wires, and remove the entire subunit. New type: this board looks like this: 
This board has the pedal sensor electronics built onto the main board. To disable them, find the Zener diode on the lower left of the board. It’s NOT a surface-mount one. Snip out this diode (see above). That’s it! | 
