You need the USB drivers for it. I would suggest that once you have installled the software you could delete the folder for the desktop software and restore the registry to the pre-installation value and the drivers might remain on the system. If you uninstalled the software after copying the drivers and hiding them somewhere then restoring them that might work too. I'm not going to try any of that but it seems plausible.
I do not believe the software is otherwise involved in the charging process - it charges without the software running.