Originally Posted by Amad3U5
This is gonna seem like a stupid question but...
You know the light on the Magsafe adapter? When it goes green, does it mean that the laptop has stopped charging? Or does it just mean that the battery is full.
If leave my laptop off and charging over-night, will it stop charging once it reaches 100%?
Yes, the green light indicates the battery is fully charged and that charging has stopped. It will always stop charging when fully charged. It cannot overcharge.
The link below should answer most, if not all, of your battery/charging questions. If you haven't already done so, I highly recommend you take the time to read it.
Apple Notebook Battery FAQ