I have a macbook Pro with Retina Display and is obviously fairly new since they were only released 6-7 months ago. I am a very cautious person when it comes to not overcharging the battery and trying to preserve the overall life of the battery. Over the past week or so I've experienced that when my battery reaches roughly 15-20%, the screen turns black and simply shuts down or goes to sleep. There are 0 warnings, notifications saying that I'm low on battery and that I should find a power source. 0 warnings and just turns off. I also have installed a windows 7 ultimate 64bit partition using bootcamp and I'm experiencing the same thing. Although the battery reaches 0%, and 100% of the time shuts down without any notice. On windows 7 it usually has a notice/warning that you are low on battery followed by a notice saying you are running on critical battery then hibernates on it's own. Now there are no notifications and shuts down on it's own. I've researched this time and time again looking for different solutions but none have worked so far. I've changed the settings on both operating systems and nothing has worked so far. could it be a hardware battery problem, power adapter charging problem, operating system problem? I'm truly confused. Also, if it is a hardware problem, will Apple Care cover it?