Yi 4K action camera battery charging station

I recently bought a few extra batteries for my Yi 4K action camera. But I needed a way to charge them outside of the camera, so I made simple 3D printed thing which accommodates two 0.6 mm blades made from FR4 copper clad board and a TP4056 charging board with a microUSB connector. Very simple to make, but very useful and actually works surprisingly well.
Some more info and photos [here](http://embedblog.eu/?p=154).