Space for the rear battery boxes

The most exiting thng that happened this summer was building the battery boxes. First thing to do was to cut holes in the car under the rear seat and trunk.

The holes for the rear battery boxes. Note the frame bar above the rear axle. 

Here it can be seen that the frame bar and the rear axle are not aligned on top of eachother.

The A2 is built using a technique calles Audi Space Frame. It means that there is a frame of aluminum tubes that supports the load rather than a monocoque that is the common way to build cars.

The Audi A2 Space Frame

The Audi Space Frame technology has been used for the Audi A8, R8, TT and the little A2. The advantage with the space frame is that the body panels do not take any load and it is possible to remove them without severely affecting the structural integrity of the car.

After making the holes I could measure for and design the battery boxes. It turned out that the rear axle and the frame bar are not aliged on top of eachother and this limits the front-to-back size of the box that is on front of the axle. I also realized that I need space for the connections to the side of the box so instead of having 12x2+5=29 cells the box will only accomodate 11x2=22 cells. My plans were to have 12+5=17 cells in the box behind the rear axle, but to compensate I made it the same size as the one in front of the axle. So, the net result is 44 cells instead of 46. This will shift the weight distribution of the car backwards, but I think I can live with that.