The two major causes of dramatic failures with the larger units are overcharging of the battery and then the shorting of the battery, lithium ion batteries fail in other devices as well, but in a laptop, it's on your lap. Thomas Kiklas More Quotes by Thomas Kiklas More Quotes From Thomas Kiklas We've put the caution out before, make sure that you use the charger that comes with the battery, and make sure the charger has a shutoff device, an automatic shutoff device, so it's not overcharged. That's typically the biggest issue which causes batteries to fail. Thomas Kiklas health-news