For Li-Ion laptop batteries (almost all the laptop batteries now are lithium-ion), there is a built-in controller inside the battery module and that chip controls how much they are should be charged. Once the battery is fully charged, it will stop the charging process. Therefore, overcharging does not affect the life span other than potentially destroying the battery. Damage to the battery from overcharging would only occur in the very unlikely event of a malfunction of the charging system.
However, there is one thing to be noticed. Over-charging occurs when the charger keeps the battery at a temperature that is warm to touch (body temperature) while in ready condition. If the lithium-based battery gets warm in a charger, there might be defects of the battery or the charger is not good. Replace the laptop battery or charger once it happens.
LaptopTraveller.com provides laptop batteries & power adapters with the highest quality for wide ranges of laptop models:.
Sony PCGA Bp2NY Battery works with Sony VAIO PCG-FR33/B PCG-K12 VGN-K30B
Battery for HP Compaq 8510p 14.4V 4400mAh Li-ion for HP Compaq NC8200 8400 NX7400 PB992A
VGP-BPS5 Battery 7.4V 7200mAh Sony VAIO VGP-TX VGP-TXN Battery
HP DV2000 Battery 11.1V 4400mAh Li-ion for HP Compaq 417066-001
Battery for Sony Vgn-TXN 7.4V 7200mAh Li-ion VGP-BPS5 VGP-BPS5A
Compaq 8510 Battery 14.4V 4400mAh Li-ion
Compaq NX8220 Laptop Battery compatible with HP NX7400 PB992A
HP NX8200 Battery chemistry: Li-ion
Travelmate 4000 Battery Acer LC.BTP03.003