This thing could be a lemon, ya know.
After about 300 full discharge cycles, your ’Book’s battery loses 20 percent or more of its capacity. But if your battery dies much sooner than expected and the computer’s less than a year old, the battery might be defective. Apple will replace a defective battery for free under your notebook’s one-year warranty (that warranty is extended to three years if you purchased the optional AppleCare Protection Plan)—see the details at www.apple.com/batteries/replacements.html. To make sure Apple will honor your request, you may want to run an analysis on your battery’s performance with iBatt 2 ($19, www.raynersoftware.com).
