For long bicycle tours using a telephone for navigation is very practical however the power need is an issue. To overcome this issue the power of the hub dynamo can greatly reduce this issue. (USB power banks could also be used but they still need to charged)
The forumslader from Jens During http://www.forumslader.de/automatiklader is a great charger for this use-case. You can decide to use the A Head version or the Kompakt version. I went for the Kompakt version because having the capability to charge a phone in your tent or recharge the internal batteries. I also needed to create a housing. The housing is a copy of https://www.thingiverse.com/thing:3148124 from 3dninjaprintor. So 95% of the credits go to 3dninjaprintor. I just made some changes. Like removing the dovetail moint. I only wanted to put the charger in my bicycle bag where it can stay dry and protected.
Technical
The first change was moving the Led and the switch to the front. I also added a small stick so you can operate the switch. I also added a hole for the Thermosensor which comes with the bluetooth pack. Second I used XT60 plugs for the dynamo connection and the 12V output instead of the mini tamyia.
When making changes note that the bottom part preview fine but the top part does not it will only show up in openscad when it is rendered.
I made the room for the Led and the Thermosensor a little to small so I would increase the ledInnerDepth a couple mm. In my case it was really a squeeze to get them in. I would also use a little less wire. I just cut the supplied wires in half, I would take 1/3 if I would have to do it again. Also the battery holder does not snap into the box, maybe I would design some place holder in the box instead of a desperate holder. In my case the printer got a extrusion problem so the battery holder is only printed for about 60% which is still fine the batteries will not come loose.
I printed the design using PLA and did not use a rubber ring for water-tightness since I don't think 3d printed designs can be very water tight without special treatment, I was only going to put it in my handlebar bag.