At the risk of additional critcism for questioning the technology, let me point out what concerns me from a logical perspective. First, I have no concern about the affect on the battery while it is charging up to 100%. However, what concerns me is what happens when it reaches 100% and sits for hours plugged in on the fast charging mode. Logically speaking, it seems to me that the fast charging mode is designed for situations that you wouldn't expect to see the phone remain plugged in for hours after reaching a full charge; you are using that mode because you need your phone charged fast. I've read that it is not good for a battery in general to leave it plugged in after the battery reaches a full charge and that most phones are designed to do some form of de-charge/re-charge to prevent damage to the phone. So, my point is that it would seem that a faster charger could present an even bigger problem if left charging for long periods of time once the battery reaches a full charge. So, when I am plugging the phone in ALL night, the fast charging would reach maximum charge even quicker and therefore sit longer plugged in on a full charge. Furthermore, if the faster charging is pushing even more juice through, then it would seem logical that it just might be worse for the battery/phone than normal charge mode for overnight charging. Now you can slam my logic if you want.