Cord to Cordless 18V Brushless Angle Grinder Conversion

I bought this tool from a japan recycle shop. It does not work properly. There is something went wrong with the armature and field. It starts to heat up after running, then more and more smoke comes out. Suddenly I knew it was gone. To fix it,​ I need to rewind an armature and field again, but I want to use it with batteries rather than electricity. I spent more than a week to do this project, finally I can do it, and you can see it is in this video. I hope you find this video useful and enjoy it! Furthermore, I am happy to receive feedback, suggestions to improve myself. !!! I'm sorry for the mistake if I did in this video !!! Thank you very much for choosing to watch my video! Have a nice day Gear Show