You don't need a charger for the Navi. It's usually a bad cable , buy a better quality and shorter cable and throw away the one that came with your navi. The mouse and Navi plug in reverse to the online tutorial. Navi in 1 mouse in 2. You can use a powered USB hub as well on input 1 might help. Also you don't want the cable to be too long or there will be too much voltage drop. Use a short one.