Having experimented with the first version obvious flaws were identified in the design of the controller subframe. First, it was slightly dimensionally inaccurate because it was lashed together. Secondly, it was unstable where it fixed to the controller, after a certain amount of yanking around the thin side arms snapped. Obviously the real subframe would be fabricated from sheet steel but this mock-up indicated structural flaws. Lastly, Li-ion18650s cells were use in the first version not LifePo4 26650s.

In this revision the dimensional accuracy is addressed, I am confident that I could send the drawings to a laser cutter / sheet bender and receive something useful that will fit the bike and hold the top cover well once welded together. The stability issues have been addressed with a simpler design so the bolt lugs brace the sides of the subframe more effectively. In addition to these amendments, real 26650 cells and accurate BMS dimensions have been used to simulate the 12v system power package better. All components still fit comfortably. Overall, I feel like I spent a very useful evening working in CAD (Cardboard Aided Design).