I usually leave my MacBook Pro sitting on my desk connected to a power adapter. Since I had the battery replaced back in October 2008, my guess is that I may have cycled through a power charge at the most 10-15 times.
However, this past week I had my MacBook Pro out and about around the house way more than usual. I would use the computer on battery a bit, then recharge it when I was done. Stuff like that. But, most of the time, even this week, I would still use the MacBook Pro connected to a power adapter.
So, yesterday (4 April 2009), I used iStatPro (highly recommended widget) to check the health of my battery. It was at around 96% after about 20 cycles. I didn’t think this was too bad. Before I went to bed, I noticed my batter was down to about 35% as I had been using it untethered to my power adapter. So I shutdown the computer, plug it into the power adapter and then went to bed.
This morning (5 April 2009) I woke up to the strangest thing. I noticed the light to my power adapter was *off*. No green light to mean the battery was charged. No red (or is it orange?) light to mean that the battery was charging. Nothing. So I removed the adapter from the MacBook Pro and plugged it back in; then the light went on as to indicate it was charging.
When I booted the computer up, I noticed the battery still had only 35% charge. What the heck? I had it plugged in all night. So I brought up iStatPro again, and here is what I found 
(except replace the 100% with a 35% because I just took this snapshot right now)
69% health after only 21 cycles!!!!! No way that is normal.
Then I opened up System Profiler and found corroborating evidence.
I tried resetting the SMC, but that didn’t help.
So what is going on here? I must be doing something wrong, right?
Will calibrating the battery help me or am I just screwed and going to have to bring the battery back to the Apple Store again for replacement?
Got the same thing going on today too. i think im just going to take it into the apple store. the light on my power adapter is gone. i charged it all night, yet my battery still reads 1%. system profiler tells me that the adapter is plugged in, but is not charging. huh?
I have the same issue here, only that my macbook suddenly shut down (like a hard power off) and then automatically tried reboot 3 times while directly shutting down again…
now the battery is showing 1:22 time to load, but it was on the charger for the whole day. weird.
Did you get any hints of the Apple Store?
chris,
Funny you bring this up. In April, I got a new power adapter and everything seemed to be working fine. I don’t take my MacBook Pro off the power adapter much at all. When I did the other day, I noticed my computer lasted only like 20 minutes on battery. I lost some work because it just shut down at 65%. I am getting a new battery. I think my lack of cycling the battery, bringing it off the power adapter more often, might have contributed to the battery becoming dysfunctional.
We’ll see. I am going to follow these guidelines every month with my new battery.
http://support.apple.com/kb/HT1490