Li-Ion 18650 Battery Protector ...and more

1st of all I want to give credit to enif (remix link) for solving the dreaded contact solution for battery boxes. The post for wrapping wire around is a great solution.

I was trying to optimize a battery holder for hobbies. I have a few early versions but they were all to tight. I decided to make use of my printer's inability to fill 1mm walls. This makes for a perfect spring at both ends of this Li-Ion cell protector. You will find this device to have good range for battery sizes. Howe