Zerotech Dobby battery case

I've bought a used Dobby drone without a battery lately and because of the not so cheap original batteries I decided to design a battery case for LiPo cells. In this case I've used two 1200mAh Turnigy nano tech cells, which have a round shape.

Update: unfortunately these cells have a massive voltage drop under heavy load. This causes the Dobby to land after 6:30 minutes although there's still a third of the capacity left in the cells. The cells are getting quite hot. The 15C rating doesn't really apply to these cells.
I will keep looking for suitable cells and post updates here.

Because of the thin walls which are hardly printable upright, I designed a kit which has to be assembled after printing. I've used super glue.
The hardest part has been the connector.The last picture shows a making of. I've used the contacts from a 2.54mm female header connector, pulled them out, straightened them, stacked and soldered them, filed the inner ones down to 1.75mm (from 2mm), soldered the c