Collecting otherwise discarded energy and reusing it as driving energy.
The regenerative braking system reuses vehicle deceleration energy. When brakes are applied or the accelerator is eased off, the rotational energy of the wheels is used to turn a motor, which functions as a generator. The system coordinates regenerative braking and the braking operation of the hydraulic brakes so that kinetic energy, which is normally discarded as friction heat when braking, is converted to electrical energy and collected by the battery for later reuse in normal driving mode. Typically, driving in city traffic entails a cycle of acceleration followed by deceleration. The energy recovery ratio under these driving conditions can therefore be quite high. To take advantage of this situation, the system proactively uses regenerative braking when running the car in the low speed range.
The same regenerative braking is used in plug-in hybrid vehicles.
Specifications may differ depending on country, region, or model.