Last night I calibrated my battery (mid-2010 15" MBP) because I wanted to see the battery health. I had a bunch of programs open and working and an external hard drive plugged in to drain the battery. After an hour like this, the warning came up that the computer was running on reserve battery, I unplugged everything and closed all programs. The computer shut itself off (it looked off, not asleep) about 20 mins after that. When I plug the computer back in about 8 hours later, the computer automatically started up, but I get a warning that the clock is set prior to January 2008 so some programs may act erratically. In fact, the clock is set to December 31, 2000. And, my wi-fi password was forgotten. I put the wifi password back in and the clock was updated with the Apple server. The same thing happened before when I accidentally let my computer die, so I know this is a recurring issue. If the battery drains all the way, the system forgets the wifi passwords and the system clock is forgotten. Why is this happening? Is anyone else having this issue? Furthermore, my battery health is 89% with only 84 cycles. Seems bad to me.