The reverse charge is accomplished by the fact that the inductance current can not be mutated. When the MOS pipe is opened to the motor coil implementation of short circuit, because the coil EMF arising from the presence of the induced current, when the tube is closed due to MOS induced current in the coil “not mutation”, thus built through the MOS tube diode for battery charging. The process is to convert the mechanical energy of the motor into electrical energy and collect and store the energy from the battery. The process of reverse charging is the process of consuming the mechanical energy of the electric vehicle, and also the process of generating resistance or braking force.

The amount of charge depends mainly on the three elements:

1, coil back EMF size. （The back EMF of the coil depends on the relative speed of the rotor and the stator of the motor. In theory, it depends on the inductance of the coil and the intensity and speed of the magnetic field）.

2, MOS tube opening and closing the length of the configuration.

3, the battery voltage. The resistance or braking force of the vehicle mainly depends on the control of the short-circuit time of the motor coil by the MOS tube.

  To sum up, the amount of charging is related to the setting of the controller and the speed of the motor. However, the resistance or braking force of the vehicle is only related to the short-circuit time of the MOS tube to the motor coil. Therefore, increasing the resistance or braking force does not necessarily increase the charge. Vehicle mechanical energy = battery collection energy + motor coil loss energy + energy form conversion loss.