If you charge your phone, and it hits 100$, and basically shows the symbol of fully charged. If you start to use it, I thought it used direct AC power, and not battery, is that correct? Because, it seems like, when I charge, then it's full and I start to use it will connected to AC power, it drops to 97%-99% and starts charging again. Could it be a faulty iphone? I just got it, a 3Gs 32GB a few days ago.