Looking at the NAV 6 the music streaming feature with NAV 6 playing and controlling music from the phone is a new feature for the NAV 6 not available on the NAV 5
The NAV 5 needs mp3 stored in its memory/sdcard then you can use the nav 5 to play/control the music. I prefer this option as it doesn't drain the phone battery playing music continuously via bluetooth.
With my set up
I have a tank bag with givi power hub installed. Power supply coming of the battery, routed around and under fuel tank, brought out on the right hand side in the headstock cavity. From there I plug in flexi/coiled cable linking to the bag and it's 3 USB ports that will charge my power bank, drift camera batteries, etc. No problems there. Plus I always see any important info on the screen of my phone like family text messages or who's calling and if it is worth answering or not. So to answer your question I have no drain on my phones battery while I play music.
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