The updated version (marked as "2" in filenames) include the following updates:
Integral 12V socket (car cigarette lighter socket)
An hole for power switch
Ver. 2 is like the green parts in the pictures of printed model
Two 3D parts which transform a 12V Lead-acid battery (sized 150 x 95 x 65mm) to a portable power station. Gives 12V and USB 5V. Using a selfie stick as an handle. At the end of the stick I added a 4W COB LED chip which makes it a convenient light pole for camping. one can attach: lights, phone charging, air pump (for inflatable mattress) and much more. Improvements that should be made:
Add the hole for 12V socket - done
Add the hole for power switch - done
Add the support for USB transformer from the bottom side - concept changed. USB is achived by plugging external "car USB adapter"
Add two metal flat springs as battery contacts.