the klx battery is 12 volts and 6ah...not sure how a usb works, but seems to draw power....even with just a usb socket plugged in (nothing plugged to the usb)...it seems to be drawing lot more power from the battery...i can see the battery tender immediately switch on to charge the battery...i would do what rgoers suggested to get a true answer if you are going to keep the usb charger on your moto...or, install a on/off switch...