Hi,
Thank you very much to all of you for your suggestions. As you pointed, the direction was wrong.
I was too stupid, since I was so excited.
I just fixed the way connecting, and now I can run with the battery. Still the gauge shows zero and the backlight is dark. I’ll try keep charging for a while.
I’m not sure, but a simple protection circuit might be available inside the orange part of a battery.
Thanks,
Shigeru