That bedroom usb outlet can be easily expanded. I installed this larger panel in place of the existing one:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
It has an on/off switch, a voltage indicator, two usb outlets and one cigarette lighter outlet. I installed a cigarette lighter outlet to usb plug to add two more usb outlets. Now we can charge our two iPhones and two iPads simultaneously. That 12V circuit is supplied by one of the 15A fuses in the converter so you don't want to overload it with more than that. That fuse also supplies power to the cigarette lighter outlet in the back of the driver's side bedroom cabinet.
David