I am a new user of Q10. I just noticed today when I plug my usb from my q10 to my tower that the battery indicator has a lightning bolt sign. I checked my battery status via Blackberry virtual expert and it says charging then after a few minutes it would say not charging but my battery meter is going up.
I unplugged and replugged the usb cable and it is doing the same thing. At home, using the wall charge there is no issues when it comes to charing my phone.
USB has a limit on the current supplied to the device, .5 amp max.
This will charge, but slower than using the OEM supplied charger (usually about .8 amps)
Now, if you have USB 3.0 with Thunderbolt on your PC (the little lightning symbol), then it will supply the needed voltage/current to your device.
This really became apparent in the Playbook, when people would plug in the the PC and see "it was not charging properly", it takes 1.8 amps for the PB, not the .5 amps supplied by the USB.