How to check the charging status of your MacBook Pro batteryby eHow Contributor
Like most laptops, a MacBook Pro comes with a rechargeable battery. The battery has a limited number of full charges that it can perform before the battery life begins to deteriorate (usually about 300 full cycle charges). If you're having trouble with your battery staying charged, your battery may need to be replaced. Here's how to check the status of the battery.
Turn on your MacBook.
Click on the Apple icon at the top left corner of the screen.
Click on "About this Mac"
Click on "More Info"
Under Hardware, click on "Power". This will show you information about your battery, including how many cycles the battery has been through, it's charging ability and so on. Your lap top battery should perform well throughout the first 300 cycles at a minimum. If not, contact Apple immediately, and they should replace the battery for you at no charge.