Hi everyone,

First of all, thank you so much for the helpful comments on my [previous post](https://www.reddit.com/r/esp32/comments/1umiu7i/killed_two_esp32_devkit_v1_boards_in_my/).

A lot of you pointed out that feeding **8.4V from my 2S Li-ion battery into the VIN pin** was likely overheating or killing the ESP32's onboard linear voltage regulator, and that VIN should really only take 5V. You also mentioned that my old wiring might have caused current to leak backwards through the GPIO pins into the motor driver.

While waiting for a proper Step-Down (Buck) Converter to arrive so I can drop the battery voltage to a safe 5V, I decided to try a completely isolated setup for a safe test.

**My New Setup (Isolated Power):**

* **The ESP32:** Powered purely via USB connected to my laptop.
* **The Motors:** Powered purely by the 2S battery pack.
* **The Connection:** I completely removed the battery positive connection from the ESP32. The *only* physical connections between the ESP32 and the MDD3A motor driver were the 4 Logic/PWM Pins (GPIO 12, 14, 26, 27) and a **Common Ground (GND)** wire so they share a reference point.
* I left the 5V0 pin on the motor driver completely disconnected.
* I also connected the encoders (3.3V and GND from the ESP32, signal pins to GPIO 32, 33, 34, 35).

Since many of you asked for a proper schematic last time instead of messy breadboard pictures, I sat down and drew everything out in KiCad before wiring it up. Sorry, if the schematic is also messy, I'm new to this.

**What happened this time:** I flashed a simple Web-Server test sketch onto the ESP32 while it was naked (unconnected). It worked perfectly.

Then, I plugged it into the circuit. I turned on the battery first. Then, I plugged the USB cable into my laptop. The ESP32 booted, but when I pressed the built-in test buttons *directly on the Cytron MDD3A driver board* to check the motors, they moved, but not really smooth. The web interface with the controls for the motor didn't work.

Immediately after, the web interface stopped responding because **the ESP32 became burning hot**. I quickly unplugged everything. Now, even when the ESP32 is completely naked—unplugged from everything except a bare USB cable—it instantly overheats near the main chip. It is completely dead.

**My thoughts and questions:** How is this even physically possible? There was no high voltage connected to the ESP32 at all.

I'm incredibly frustrated. Please take a look at my attached KiCad schematic and tell me if you see the smoking gun.

Thank you so much!

Update: I just fried my THIRD ESP32. I made a schematic, switched to USB power, and it still died. Please help.