Hello all. I searched for an answer to this, and didn't see one, so please excuse me if this has been covered. I have an iPhone 3G which I wanted to test out as an all day GPS device while driving in my work van. I have a very new laptop, and I left the iPhone plugged into a USB port on the computer as to allow it to remain charged. I used the iPhone all day, using the GPS tracking instead of my usual map book to go from appointment to appointment, and of course, it worked great. But towards the end of the day, I noticed that my battery was draining, and even got down to about 25% according to the battery indicator. I switched to a different pair of USB ports on the computer to rule out the possibility that one may be a set of 1.1 ports and the other 2.0, but it continued to drain, even though the iPhone indicated that it was charging, both on the indicator (the electric bolt) and the lock screen (which showed the actual battery charge level while prompting to "Slide to Unlock"). The only thing I could think of was that, even though it was charging, it couldn't keep up with the power drain. So I exited the Maps app, and opened Scribble as it seemed to be the best bet to not use any power-draining services. Within 20 minutes, my charge level shot back up to 50%. So, is the GPS using that much power, or is the phone just not charging while using GPS? Has anyone else had a similar experience?