I use a hub dynamo in combination with a USB charger. When I am navigating, the phone still gets drained but at a so slow pace that it can be tolerated. If the phone is idle, it charges. The phone mounting relies on velcro with interspersed hooks and loops. A power bank has those on its 2 sides, so can be sandwiched between mounting plate and phone. Also, the bank can be put onto my body, with just a cable running to the phone. The bank is just a highly intelligent shell into which I put the highest quality 18650. If it rains solid, e-thing can go onto my body, but an alternative f/navigating is a clear waterproof pouch, again w/velcro.
Last edited by 2_i; 05-15-22 at 05:28 PM.