I was inside the local YMCA for about 15 minutes when I noticed that the front pocket I was carrying my Droid Charge in felt a little too warm. I removed the phone to find it excessively hot. I removed the back cover and the battery was hot to the touch. I wasn't sure what the problem was, so I quickly looked for a sensor program, found AndroSensor, and then downloaded it. By the time I had the program installed, the battery temp was showing 107+ degrees F. I rebooted the phone to see if it would help. I also remembered that I had left LTE turned on from a trip I had taken a few days ago. I set it to back to CDMA mode since I live in a 3G only area. It took about 15 minutes for the battery temp to drop to around 85 degrees F. An hour later it's about 80 degrees F. I have no idea what caused this, but it does concern me that the phone could get that hot.