at the time of death, this could be quite normal. Your PC's viewing of the % of power remaining may not be accurate either. Battery time will decrease with age as a normal course. It is possible that a charging circuit can damage or decrease battery life but it's usually the battery itself. In a quest for bringing down the cost and weight of laptops, I think manufacturers are installing lesser capacity and/or cheaper batteries. Some such as IBM offer higher capacity ones at a premium.