The phenomenon of overcharge is caused by several reasons. One of them is malfunctioning of tension regulator of the vehicle. The regulator has to manage tension (voltage) sent by the alternator of vehicle to the battery and the electrical system. The battery, instead, has the function to store charge for subsequent consumption.
In general, tension can vary between 13.8 V e 14.4 V. Every time that the limit exceeds 14.4 volts, overheating occurs in the battery generating overcharge. It can be constant or intermittent, depending on the origin of the problem.
The tension regulator has another important function. Every time that temperature increases in the motor compartment, the tension regulator should compensate thermic increase by decreasing regulated tension, and consequently current which is being sent to the battery, avoiding that maximum temperature limit is exceeded. Malfunctioning of regulator can compromise lifetime of battery.
The use for long periods of time of electrical and electronic components in the vehicle with engine off can also create overcharge as battery, once deeply discharged when activating the starting engine and the vehicle engine, will sign to the alternator that it has no charge.
Nowadays, alternators are considerably powerful. With information that battery is discharged, currents of 40, 50 or 60 amperes or higher are sent to battery, causing an overcharge, which is called overcharge by misuse.