Hey guys, I have a small company that makes an app for farmers that uses GPS to detect their time on the fields. We have some farmers running on Viewpad 7 tablets. Their normal household charger for the device has output of 5v and 2 amps. So we found a 12v car charger for their tractor which outputs 5v and 2,1 amps. But after 10-12 hours of running the app (with full screen contrast and active GPS) the battery will run dry.. completely dry. Do you know why this is? Could it be the standard USB cable that cannot deliver 2 amps from car charger to device? Or is device using more than 2 amps for screen and GPS? Help!