If I remember well, I saw somewhere that the Bug can charge internal battery from the mini-USB port.
When I work on my Bug with only the USB cable pluged, the red charging led is on. But on the LCD screen the battery icon is not set on charging mode and it effectively doesn’t charge. After the same time as without any cable pluged, the battery is empty and the Bug switch off.
So, the question is : is it normal or should it charge with mini-USB on ?
The BUG can charge via the the USBOTG, but the draw is much larger than that supplied. The result is that while the mini-usb is providing some current, it’s not enough to sustain a constant power drain.
It is recommended that you use the AC adapter when using the device.