'11 R1200RT '12 F800GS
USB power source
I built this so that I could power my iPhone 4, which will be attached with a RAM mount or left in the "glove box".
I purchased a cigarett lighter USB charger from an auto parts store and removed the voltage regulator circuit board. (Look for a model that is assembled with screws.) I mounted the c/b with two-sided foam tape in a kit box from an electronics store. The BMW dealer supplied the connector for the 1200 RT's wiring harness. The three wires are encased in heat shrink and passed into the box with a grommet. I soldered the wires directly to the c/b rather than splicing the wires.
The USB cable is routed out of the box at the lid so that a "split" grommet could be used. The two pics at the bottom show the wiring harness connector and the box tucked under the fairing and held in place with two sided foam tape. When not in use, the USB cable is tucked into the glove box.