When it gets to a certain point, (-5%?) it will start hibernating. This means you plug in the battery and power adapter and the computer outright doesn't see any battery, because the controller isn't talking. It's hibernating. It will wake up briefly every 5 minutes or so to see if anyone is tapping it on the shoulder. If so, it then gets to talking, and the battery starts accepting a charge, recovering it from hibernation. This is why if you have a deeply discharged mac battery you just have to plug it in and wait.
That is what my old cell phone battery used to do. Was wondering about that. Thanks.
