A couple of months ago I entered the world of CarPlay/Android Auto, putting a (much cheaper, much less sophisticated) Aoocci C6 unit on my Royal Enfield Meteor 350. I mention this because I'm powering that unit with the Meteor's stock, ignition-only-on, USB-A port, and that unit works fine being powered that way (even though Aoocci asserts that USB power is for "testing only," or something like that).
My opinions on your options:
1) With direct-to-battery, would you have to remember to turn the unit off each time you shut down the bike (to avoid draining the battery)? If so, not very convenient.
2) I use the otherwise unused satnav connector to power some LED modules up front. These are not driving lights, but rather just extremely bright but low wattage conspicuity modules. I have a write-up on this -- pics, captions, links -- in my 400 gallery, starting with this image:
There are about 20 pics on this, most of which are irrelevant to your situation, because they're about cable routing, etc.
In any event, using that connector has worked flawlessly for me. The power to that satnav connector goes off 60 seconds after you shut off the bike.
3) With the USB port, I'm assuming that you're talking about the USB port in the right-side cubby. (From your other thread, it looks as if you're getting a '25 model. I assume that those still have the port(s) in the cubby, although I don't know whether BMW has changed from a USB-A to a USB-C connector.)
In any case, if you decide to go that route I would recommended adding an
external USB port, as opposed to using what I'd call an internal, i.e., inside the cubby, port.
When I was on a week+ tour of the Alps in 2023, I used the internal port on a C 400 X to power my GoPro; see the second pic at
https://billanddot.com/Ultimate-Alps-Tour/. This meant that I had to mush the cable in a corner of the cubby door; this is a method that worked, but I would not want to do that on my own bike, and on a permanent basis.
Instead, on my former '22 and on my current '23 C 400 GT, I added an external port on the dash. You can read about that mod in my gallery, starting with this image:
There are about half-a-dozen pics on that.
Note that the 3BR Panel TAPP that I bought for the '22 had a 12V requirement, and so I tapped into a 12V source on the bike, as described in those images. When I ordered another one -- when I got my '23 -- 3BR had changed the power input for the Panel TAPP (
https://3brpowersports.com/products/tapp™-panel-mount-adapter) to a plain old USB-A plug. So I did not have to tap a 12V source from the bike, and just drilled a bigger hole in the back of the cubby and then just plugged in the Panel TAPP to a USB-A port in the cubby:
View attachment 5834
In any case, I've been powering my GoPro for three years on a 400 using a Panel TAPP (and had used that product on a couple of bikes before that, too -- 3BR makes good stuff).
The power to the cubby ports shuts off shortly after the bike is turned off, but I don't know the exact time involved. Oh, and if BMW has switched to USB-C in the cubby, then you would need a small USB-A-to-USB-C adapter, of course, if you used the Panel TAPP.
Those, it seems to me, are your options. I hope some of my response helps you out, and perhaps gives you some ideas. Good luck on your project ... and your new ride!
