My first task was to figure out how I would mount the battery. the external mount sticks out side ways from the water bottle mount. I didn't like that. So, I found some 1.5" angle aluminum, mounted it to the water bottle bosses, and then moved it around till it seemed to fit.
This puts the battery mount facing rearwards between the stoker seat tube and the rear wheel. The chainstays are long enough I have no problem fitting it.
All of the wires exit out of the bottom and run under the stoker bottom bracket.


Angle Aluminum with a couple of holes drilled for water bottle mount. Test setup

Angle Aluminum with a couple of holes drilled for water bottle mount. Test setup

Making the Aluminum mount a little more refined.

Inside of the mount

Finished fitting