I'm actually in the middle of this type of project right now. I have the parts on order but haven't started any of the work yet.If anyone knows of another 12V location under the fairing (without having to cut/splice factory wiring) please let me know. Good to have options.
I'm using the method outlined in this video:
Here's the parts I ordered:
Less than $16, no splicing, and easy to undo with no changes to the bike if it's not working or starts causing problems.