Intro: DIY Coin Cell Battery Charger for 0.3$
Watch the video to see it working:
Step 1: How It's Done..
I designed and made the base with my 3D printer. If you want my design just drop me a comment.
If you don't have a 3D printer just make any base that can hold the battery with a good contact.
Then you will need to change the resistor that I marked in the video with a 33k one. It's not that easy to solder the resistor as it's less than 1mm! so if you are not skilled enough, you can use a bigger resistor with the same value (33k).
Then connect the output + and - to your copper and screw (make sure of the polarity to match the battery).
Glue the parts with some glue (I used thermal silicone).
And Happy charging!