Regenerative braking is only found in ALL ELECTRIC vehicles and some electric hybrids.
To use the term “Regenerative braking” is a misnomer when covering the subject of Variable Voltage Alternator operations in conventional vehicles, because conventional vehicles do not have regenerative braking, it is simply variable voltage algorithms, controlled by the ECU/BMS which act according to whether the ACCELERATOR PEDAL is pressed or not pressed and has absolutely nothing to do with applying the brakes.
While it may sound trivial, it is actually quite an important difference. If the battery was only able to be charged while braking, the total amount of time spent charging the battery during each drive would be VERY short and you would have no chance of replacing the energy used while starting the motor.
The actual amount of recharging time is much greater thanks to this being carried out when ever you lift your foot on the accelerator peddle.
Furthermore, the alternator operation is based on a number of factors, but the primary charging of the cranking battery is achieved using the KINETIC energy of the vehicle, again you lift your foot on the accelerator peddle.
Also note, this type of “CONSTANTLY” Varying Voltage Alternator operation is primarily used in vehicles equipped with STOP/START function. There are exceptions, like some later model Land Rovers, both with and without STOP/START.
Anyone can test this at anytime. The next time you are driving up a hill and the voltage remains low. Then as you crest the hill and coast down the other side, as you lift your foot off the ACCELERATOR PEDAL, the voltage rises to what ever the BMS requires.
Turning on headlights or air conditioners can also have an effect on how low or high the alternator voltage is set at.
The one over-riding factor is the actual state of charge of the cranking battery.
If the BMS determines that the cranking battery is in a low state of charge, the BMS will ignore whether the accelerator peddle is pressed or not pressed, and will maintain a CONSTANT voltage till the BMS determines the cranking battery is in a high state of charger.
This CONSTANT voltage is usually around 14.6v - 14.7v
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