Battery on my 19-month-old 15" Penryn MBP has been acting up for the past month or so. Here are my symptoms: - shuts off instead of sleeps when running off battery; usually this happens within 5 minutes if there is any activity--if i leave the computer alone it will go into sleep mode or at least last much longer - obviously wrong readings displayed percentage-wise and time-wise when on battery; lights on battery often show enough charge to power up MBP but still does not turn on - no consistent 'trigger' percentage that shuts it down; rather it coincides with activity (though it never makes it below 30% or so) - system profiler --- 374 cycles , condition GOOD (few days ago it read POOR) - maximum battery charge: 655336 mAh (WTF?); original 5600 - perfectly fine on AC I have tried calibrating, but not sure it was done properly as I could not drain the battery fully without the computer shutting off on me (won't turn back on unless plugged in). Reset PRAM. I'm wondering if I should go ahead and shop for a new one or if I can try some other solutions. Also worried if all of this shutting down/starting back up is harmful to my (beautiful, newly-purchased 500GB) hard drive.