The battery of my MBP has started doing funny stuff - even though I've tried calibrating it (iStat says it's at 50-ish% health after 150ish cycles). I was using my MBP when, with about an hour of operation left and without warning, the computer died. The battery LED was flashing fast. Later that day I opened it and it worked again for about 30mins before sleeping again, so I thought I'd leave it until it didn't even have the power to sleep before I recharge it. That was more than 48hrs ago! My MBP is still asleep and won't wake up. How long should I leave it? Should I take the comp back to Apple - is there a fault?