Your MacBook's Built-In Battery
Your MacBook’s built-in battery might appear to be maintenance free, but unfortunately, that’s not the case. Consider these tips as your rules of the road for monitoring and charging your battery:
Recharge in sleep mode or when powered off. Your battery recharges faster when your laptop is off or in sleep mode.
Keep your laptop plugged into an AC socket when possible. Take every opportunity to top off my laptop’s battery, and so should you.
If you don’t have much time to charge your battery before you’re away from an AC socket — say, half an hour — don’t use your MacBook whilst it’s plugged in and charging.
Save your juice. For the most juice you can scavenge, here are some easy tricks:
Turn off your laptop or leave it in sleep mode.
Turn off unnecessary hardware. To conserve battery power as much as possible, disconnect any USB, Thunderbolt, or FireWire devices, and turn off your AirPort and Bluetooth wireless hardware if you’re not connected to a network.
Reduce the brightness of your display from your laptop’s keyboard by using the F1 key.
Monitor your battery level from the Finder menu. Your laptop’s battery life can be displayed in the Finder menu in several different views. To display the percentage, click the battery icon in the Finder menu and choose Show→Percentage.
Keep in mind that the percentage shown is estimated using your current System Preference settings and power usage, so if you change your Energy Saver settings or remove a USB device that draws power from your laptop, you’ll see that change reflected in the battery meter.
Calibrate your battery. You can train your battery to provide the maximum charge by calibrating it, which Apple recommends doing monthly. It’s a snap:
Charge your battery until the Finder menu battery meter indicates that the unit is fully charged at 100%.
*Keep your laptop connected to an AC socket for another two hours to ensure a maximum charge.
Disconnect the power cord and use your laptop on battery power until it’s fully discharged and it automatically switches to sleep mode.
Although Lion’s new Auto Save feature helps ensure that you won’t lose any data, it’s still a good idea to close all your applications when you see the low battery warning dialog box.
Allow your laptop to sleep (or turn it off) for a full five hours.
Reconnect the AC cord and fully charge your battery.
If your battery is no longer holding a charge — in other words, if you fully charge it and unplug the AC adapter, only to discover that you have only a few minutes of battery life — it’s time to invest in a replacement battery. Owners of the latest MacBook models must take their computers in for servicing because today’s Apple laptops are sealed units, and you can’t replace the battery yourself.