Just thought I’d share. My Garmin GPS runs on 5v (e.g. USB) power. Their latest Zumo (and DriveSmart) units all come with cables that convert 12v power to 5v power at the mount. Of course, they also plug directly into a USB port, but that’s a separate power supply port and is also used for Syncing. For their new Zumo units, they provide a proprietary cable that connects to 12v on the supply end and 5v on the device end - with a converter box in the middle (actually near the 12v end.)
What I wanted to do is mount my Garmin 365 on the handlebars of my Heritage Softail, but provide power through the USB port I had previously mounted up on the steering head - rather than run another power cable up to the front.
Similarly - I wanted a quick-disconnect of the mount itself.
I came up with nifty solution to both of these problems. (Though a little scary at first.) I basically cut off the mount cable near the mount, then I provide 5v supply to that cable in a couple of ways. To connect the two I found a nice compact little waterproof connector. (https://www.amazon.com/gp/product/B01LCV8DXQ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1) These connectors are waterproof (they say) to IP65. Remember, the Zumo units and mounts are inherently water resistant (IPX7).
For the USB mount - I found this cable below (https://www.amazon.com/gp/product/B07GN3XQ7N/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1) that terminates in nice two wire ends (Black and Red) as well (after you cut off the plugs they come with.)
The nice thing is - they both have a nice pair of Black and Red wires - so it’s natural to get them connected correctly.
Holler if you have any questions - or even want a pair made up.