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 re calibrated from time to time to keep the onscreen battery time and percent display accurate and to keep the battery operating at maximum efficiency. You should perform this procedure when you first use your computer and then every few months after that. If you normally leave your Apple portable computer connected to AC power and very rarely use it on battery power you may want to perform this process once a month. The website www.apple.com/batteries has more helpful information regarding batteries and offers an iCal calendar to remind you to calibrate your battery.
Here are the steps to calibrate your computer’s battery:
1.Fully charge your computer .
2.Once fully charged, leave it plugged in for at least another two hours.You can use your computer at this stage too.
3.Remove your adapter and use your computer till you get a battery level warning message.
4.Ignore that message and continue to use your computer.
5.Eventually the machine will go to sleep.
6.Do not plug it in. Instead let it sleep for at least 5 hours.
7.After the time has passed,plug it in and let it fully charge.
8.Once fully charged,your battery has been perfectly calibrated.
Note:For most favorable results,calibrate your battery for every 2-3 weeks.
It is also better to follow some of the tips mentioned below :
a) Turn off Airport if you are not using it.
b) Turn off bluetooth if you are not using it.
c) Minimize the use of iSight camera as it consumes a lot of power.
d) Remember to eject all the discs from the super drive.
e) Reduce screen brightness to as low as you can comfortably work.
f) Turn down/off the backlit keyboard during the daytime!
g) Turn down volume or use headphones.
h) Run fewer applications at once/turn off un needed applications.
i) Do not ever disable a CPU core.
Hope you got good information from this post!