A:Answer The battery does NOT charge all day. It charges until it reaches a maximum, which is 100% when new, but which gradually goes down with time. What happens is that you will be using power from your charger instead, until the battery reaches a certain point, around 90%-95%, at which time it will charge again to the maximum. This is called a "trickle charge" and happens repeatedly until you disconnect the charger, and each time, the level at which it starts to charge again gets lower, until at some point it will be so low that the battery is no longer usable. This whole process takes years, but not so long as using the battery in a more "normal" way (i.e., frequent use without the charger connected).