Why did the laptop show that the battery is fully charged ...

Q: Why did the laptop show that the battery is fully charged after just 10 minutes of
charging?

A: It is quite normal for rechargeable battery that the laptop shows it is fully charged after 10 to 15 minutes of charging when you charge the battery for the first time. All you have to do is discharge the battery till laptop shuts down, and then fully charge your computer's battery until the battery indicator lights turn off and the adapter plug light goes from amber to green, which indicates that the battery is fully charged, and the battery recalibration process is completed.