I have seen issues in the past when attempting to charge via USB to PC. It seems that some USB (A to Mini) simply do not carry the charge efficiently, or are missing a crucial trace through the cable for the Kobo to charge properly. I experienced one case where I had charged the Kobo for 5+ hours, only to be welcomed to a entirely black screen (dead battery). Connecting to the USB connection in my car started the Kobo up fine.
I would recommend you try a different USB A-Mini cable connected to your PC and see if that helps.
|