Nowadays, it is believed by many people that leaving your laptop charger connected while the battery is fully charged destroys the battery. The funny part about it is that when you ask one of these people the origin of this believe, it's always the same response; "someone told me so", and it is even funnier how none of them ever has any explanation as to how this happens.
Your laptop battery cannot get overcharged. The laptop charging circuit is designed such that when the battery gets fully charged, current is no longer supplied to the battery. These chargers are automatic in the sense that they are built with a voltage sensor circuit incorporated into them to sense the voltage of the battery under charge. The charger automatically switches OFF when the battery voltage reaches the set optimum level, meaning no power is supplied to the battery at this instant.
