You won't need to charge the Sena during the day. I have gone 15 hours easy with mine. Yea, the aux charger can come lose.
Run a ground and switched hot up the center of the triple T. Secure it on the frame side and on the handlebars. Then get one of the below and you can use any usb cord you like for whatever device you have. It has plenty of power to fast charge the newer phones. It fast charges mine while I Nav and play tunes.
Just secure it with that double side 3m white sticky tape stuff.
https://www.amazon.com/gp/aw/d/B01DYE54LI/ref=ya_aw_od_pi?ie=UTF8&psc=1