Dell laptop batteries contain a computer that keeps track of the charge. Sometimes, it needs to be recalibrated. Follow the steps below to perform a recalibration:


  1. Connect the AC power adapter to the laptop and let it charge to 100%.
  2. Shut down the laptop by clicking the Windows Start icon, then the power icon (looks like a zero with a one inside), and then "Shut down". 
  3. Disconnect the AC power adapter from the laptop.
  4. Turn the laptop on and immediately start tapping the "F2" key about once a second until the laptop enters setup mode.
  5. Allow the laptop to run until the battery is completely discharged and the laptop turns off.
  6. Reconnect the AC power adapter and allow the laptop to charge for at least 2 hours.