I have a 510 USB PT that I use while I'm working at my computer, and sometimes while I'm watching TV and working on my laptop. With the battery in the line, should this be plugged into the USB port most of the time, or occasionally unplugged to keep from "over charging" the battery? I'm pretty sure you can't really over do it on the battery, but I'm not sure what the correct way to use the PT is. I guess all the users manuals are written in Chinese.