Wow,I slove the issue of the batteries for my MacBook like this...

 

As Scot Marburger wrote, I too had a similar problem on one of the batteries for my MacBook (I have two batteries). One of them, the one I bought about 2 years ago (3 months after I bought my MacBook) would shut down without any warning anywhere between 60-50% of the Apple A1245 battery charge.
Before I went to the local Genius Bar, I tried to recalibrate the Apple A1080 battery (which turned out to be rather hard, when you can't get down to below 60-50 % of charge to begin with), reset SMC, zap PRAM/NVRAM, check the battery health status, etc. Recalibration, SMC/PRAM/NVRAM reset did not help at all. The PowerBook G4 battery cycle count was around 230 at that time. The battery in question was, however, not showing any of the four typical symptoms of defective batteries.

When I visited the Genius Bar last week, they asked me a few questions and checked the Apple 13-inch MacBook Air battery with their special diagnostics software. Not surprisingly, it came up as a bad battery. However, they just were not willing to replace the battery for free. The best I could get was an "offer" of $99 for a "new" battery that comes with 3 months warranty. I declined that offer, given I can buy a new battery for $129 with 12 months warranty anywhere (not to mention that I qualify for the educational price of $116 with 12 months warranty: $17 saving for 9 months of fewer warranty just did not make any sense to me).
What I thought interesting was, as far as I could tell, they did not even check the serial number of the A1079 battery to see how old it might be. I was simply told that the battery is out of the warranty and the best they can do is the $99 deal (which is hardly a deal if you ask me).
A few days later, the same Apple A1012 battery finally gave up. My MacBook no longer sees the battery being there and I get "X" shows up in the menu bar. This time, instead of driving across the town, I gave a call to Apple asking about the possibility of the battery replacement.
The Apple tech lady I talked was very nice, but was unable to give me a replacement Apple PowerBook G3 battery. She checked with their specialists to see what she may be able to do, but she was told that since my battery is not within the serial number of the defective batteries, therefore, no chance for a free replacement.
So, I ended up ordering a new Apple A1039, which arrived today. My other battery, by the way, which came with the machine is still going strong with around 400 cycle counts. As far as I can tell, it's not how I am using the machine/battery, based upon what I see on the original battery's performance. I may still try with the local Apple Store one more time, but so far, I have not been very impressed with Apple on the M9756 battery issues.
Resource: Wow,I slove the issue of the batteries for my MacBook like this...