Re: Running power into top case
One potential issue with many of these solutions: radio interference. I've tried 6 different DIN plug charging adapters on my R1250RT and every one of them gives incredible audio interference when FM or Satellite radio is used while a phone is charging. They're electrically quiet when not powering a phone, but noisy when powering a phone.
In the end, I keep one in my tank bag to top up a phone in an emergency, but normally I use a backup battery/powerbank in my tank bag to charge my phone. Lasts more than all day.Currently using one from Amazon with a fold-out triple solar panel. On a bright day I can leave it open on the seat at stops and add some power back, but even running my phone all day has never drawn the battery down beyond 75%.