ESP32 Forum

Hi ESP 32 Community,

I am happy that I found this place.
I am a esp and microcontroller beginner and playing around with a WeMos lolin esp 32 and distance sensors. Anyways I bought 3.7V LiPos and charged one just fine with the esp32. Afterwards I wanted to run the esp32 on the lipo and connected first the USB (to upload the code) and then the battery. Afterwards the esp32 smoked and is dead.

This site provides information about schematics etc if necessary: https://www.wemos.cc/en/latest/d32/d32.html

Now I am wondering what happened, was the sequence (USB then LiPo) the problem or is there an issue with my approach?

I am really glad about any help.

If your board confirms to the schematic, it's very unlikely that connecting both USB and battery, in whatever order, caused the ESP32 to smoke. There's a circuit that disables the battery when USB is connected, and even if that would fail, the result would be the battery being damaged and not the rest of the electronics going up in smoke. I think you simply either had a board that was defective from the start, or did something else that caused the thing to release the magic smoke.

Hi ESP_Sprite,

Thank you for the quick and informative reply.
Since nothing else was connected, the only issues could be the LiPo, board or USB multimeter (to measure current draw).
I have quite a cheap board, so maybe it was broken from the beginning. Or I messed up the soldering.

I have a few boards left, I think I will just try again.
Thank you for the advice.

In my second try I think I found the issue. My battery has a different jst connector than the lolin32 board so I used an adapter. However the black and red cables are the wrong way when connected. Since I can not find any other jst 1.25 to 2.0mm adapters, can I just cut them and resolder them in the correct way?
Sorry if that is a dumb question, I am learning

That'll kill the devboard indeed. Yes, you can cut it and resolder them, make sure that the wires can't short (ideally use heatshrink tube to isolate them, if not tape will work)