Customer:
I just got a 3.7V 3700mAh battery and when I plugged it in, one of the chips in the charging circuit burst and burnt me.
Originally submitted via email support on 9 July 2021. Migrated to the forum for community visibility.
Soldered Support:
Check your battery polarity against the marks on the PCB. Can you send a picture so we can verify the connection?
Customer:
The battery polarity was opposite to what the board required. I had assumed the JST connector used standardized polarity, but that was incorrect.
Soldered Support:
The board should still be working otherwise, but you will need a replacement battery charger IC. If you can solder, let me know and I can provide you with the exact part number.