Last week I was on vacation. My alarm was set. When I woke up, my phone was off. Luckily had woken up on my own accord just prior to it going off by about 20 minutes. The battery was full charge. Today (last night) I woke up to my regular alarm going off, which confused me because it was set a little later than my phone. I hit the button on my phone, hmmm... it seems to be turned off... Fired it up... battery was full charge (charged it all last evening). So uh... what could be doing this?