The battery is equivalent to a capacitor with a large capacity and has a certain voltage stabilizing effect. It has a good filtering effect on the fluctuation caused by power frequency (equivalent to voltage stabilization), but has little effect on the voltage fluctuation caused by pedal speed. When the battery starts to charge when there is no electricity, the voltage fluctuation has little influence on the battery. When the battery is almost full, if you press the pedal quickly for a long time, it will have an impact on the battery (the battery is easy to break down). The arrow refers to the capacitor. The black one may be a rectifier filter capacitor, and the blue one may be a battery storage buffer capacitor, all of which can play a role in filtering and stabilizing voltage, preferably (especially for small-capacity batteries). Flywheel can stabilize the speed, and then play a certain role in stabilizing voltage.