Based on Apple’s calibration tips, it looks like the iBook, PowerBook, MacBook or MacBook Pro are smart enough to go to sleep before they battery has hit a dangerous low that is good since the batteries are expensive. Still you must, when you easily can calibrate your laoptop MacBook or MacBook Pro lithium ion battery for best performance.

The battery has an internal microprocessor that provides an estimate of the amount of energy in the battery as it charges and discharges. The battery needs to be recalibrated from time to time to keep the on screen battery time and percent display accurate.

• Plug the power adapter in and fully charge your macbook’s battery until the battery indicator lights turn off and the adapter plug ring goes from amber to green, which indicates that the battery is fully charged.
• Disconnect the power adapter and use your Macbook. When your battery gets low, you will see the first low battery warning dialog on the screen. Continue to use your Macbookuntil it goes to sleep. At that point the battery has been sufficiently drained for calibration.
• Connect the power adapter and leave it connected until the battery is fully charged again.

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