I have a Droid Razr that is used as a hotspot only. I'm wondering what are the risks of leaving it plugged in all day when the hotspot is on due to battery drain. I unplug and turn off hotspot at night. It does get a little warm where the cord is plugged into the phone. If it is plugged in all the time will the battery just die from over charging? Will the phone still work if plugged in and the battery is gone/ dead?