Yeah, cos my company deal with rechargable battery power device.
Some IA students help us did some research on battery before. It
said that to prolong the life span of Li-ion battery, it is best
not to let it emptied.
For overnight charges, I am not very sure on it. But i think it is
to prevent the battery from overheating or to prevent the internal
parts from malfunction. But I do know that most devices have an
auto cut off when the battery is full.
But just to play safe, do not charge overnight.
Just to add on, if you want to use the device with the adaptor
switch on, like charging it while using it, it is better not too.
For example, you want to play with your laptop using fixed power
line, take out the battery if possible. This will prevent your
battery from malfunction because of the heat from the laptop. Same
goes for other device.
http://en.wikipedia.org/wiki/Lithium_ion_battery
Look under Guidelines for prolonging Li-ion battery
life
