4x18650 Battery Pack

Battery holder for 4 li-ion batteries of 18650 type.
you can connect the batteries in the following options:
2 parallel, 2 serial
4 serial
2 serial, 2 parallel.

I used copper sheet for the contactors.
I made it for my RC boat and connected it 2Px2S which gives about 8Volts.
I added 4 rectangular holes for optional cover which has to be designed.