Well I always knew that lipo's can not be fully charged for extended periods of time... I have always seen that, like BrianG mentioned, it was an issue of cathode (or anode?) corrosion that starts to happen around 4.0volts, and increases exponentially as voltage increases... I remember reading this somewhere, but I am at a loss about where. Also, I find it convincing enough that battery makers state the same thing, as you would think they wouldn't mention anything, as the shorter a battery lasts, the sooner you have to buy a new one. Unless... it's a conspiracy on the pack makers, and it's actually damaging for them to be anything but fully charged? (highly doubtful)