The charge controller is a separate element of the autonomous photovoltaic systems. It is also known as charge controller.
Being an installation in which the energy generated by the photovoltaic modules is not supplied directly to the mains will be needed batteries.
To charge batteries safely charge controllers play a key role in both the loading and discharge the battery.
The charge controller is limiting the energy that is supplied to the battery and when the battery is charged, if he continues to supply energy, become hot and could create a dangerous situation.
In the section of solar photovoltaic, you can find more information about charge controllers.