How To: Recondition your Battery if it is losing it's charge quickly

If you find that your Macbook battery has started losing its charge quickly, say lasting only 2 1/2 hrs vs. 8 hours, you may need to recalibrate the battery.

To perform a full cycle through the battery’s life, perform the following teps:
  1. Plug in the power adapter and fully charge your PowerBook’s battery until the light ring or LED on the power adapter plug changes to green and the onscreen meter in the menu bar indicates that the battery is fully charged.
  2. Allow the battery to rest in the fully charged state for at least two hours. You may use your computer during this time as long as the adapter is plugged in.
  3. Change your Energy Saver preferences to Never Sleep
  4. Disconnect the power adapter while the computer still on and start running the computer off battery power. You may use your computer during this time. When your battery gets low, the low battery warning dialog appears on the screen.
  5. At this point, save your work.  Continue to use your computer; when the battery gets very low, the computer will automatically go to sleep.
  6. Turn off the computer or allow it to sleep for five hours or more.
  7. Connect the power adapter and leave it connected until the battery is fully charged again.
  8. Perform an SMC Reset on Device
  9. Turn on Device and reset your Energy Saver Settings to desired values.

Even though safe sleep mode will save any open files when your computer goes to sleep, it’s a good idea to save everything and close your apps before it goes to sleep. Once you’ve run the calibration cycle, your computer will have a much better idea of how much power is really left in your battery.

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