ESP32 Forum

My power source is from LiPo batteries connected in parallel (3.8V, around 6A using multimeter). Then I connect this to a step-up booster converter (bought from Amazon - DCV-R43 MT3608 LM2577 DC-DC Boost Converter Voltage Regulator Step Up Power Supply Module) to reach 5V. The output current from the Vout of the step-up converter is around 600mA.

Now the issue is when I connect it to the Vin pin 5V of the ESP32, it just turns the LED on but does not operate anything. But when using the USB cable to power on the ESP32, it operates normally and runs the uploaded code. I have read several advice from other forums like adding a 10uF from EN pin to the GND and also connecting pull-up 10k ohm from GPIO 0 (that is BOOT button signal) to 3V3. But still, the same issue occurs. It just turns on the led but no operation from the ESP32.

Many forums have similar issues but I cannot see a clear solution for this. Hoping for support here. Thank you so much in advance!

My ESP32 was from Amazon - KeeYees ESP32 ESP-32S Development Board 2.4 GHz Dual Core WLAN WiFi + Bluetooth 2-in-1 Microcontroller ESP-WROOM-32 Chip CP2102 for Arduino

When you power it from the batteries do you get 3.3v on the 3.3v pin?
Is EN and GPIO0 pins high ?
did you try pressing the reset button after you connect the batteries.

username wrote: When you power it from the batteries do you get 3.3v on the 3.3v pin?
Is EN and GPIO0 pins high ?
did you try pressing the reset button after you connect the batteries.

Yes I get 3.3V on the 3.3V pin.

EN pin is connected to the GND pin. How do I check if EN and GPIO0 are high?

Yes I also tried pressing reset button but still the same issue.

username wrote: When you power it from the batteries do you get 3.3v on the 3.3v pin?
Is EN and GPIO0 pins high ?
did you try pressing the reset button after you connect the batteries.

Update:
Yes, 3.3V are measured in 3.3V pin
EN pin is high (previously it was connected to the GND) and GPIO0 is high. both in 3.3V
Yes I have tried pressing the reset button but still has the same issue.

Hi, just a quick update. I have now resolved it. I've rearranged the circuit and it just worked perfectly fine. Probably the issue prior was it needed to have fewer wires to make sure the current would provide enough.

I have the same problem.

ESP32 dev kit c (v4?) connected to 5V and GND (nothing else connected)
Flashed with Tasmota

When powering via USB, everything works fine, but when using external 5V I just get a blinking onboard LED (3x flashing then 500ms pause)

Video of behaviour: https://youtube.com/shorts/eiI4YbPH22Q? ... AoyLdeTOHW

Any helpful tips?

BTW: voltage between 3.3V and GND is 3,25V

Try to twist the pair of power supply lines before connecting them to +5V and GDN pins.

A common cause of this issue is the bootup time.
When a microcontroller boots up, your code in microcontroller may try to connects to other components. If one of these components have not initialized yet, your MCU will fail to communicate with the component. If no retries are made, your system is stopped.
More clear, Your ESP32 is initialized faster than another component.
This happen is not only for ESP32 but any MCU.

Solution: Add a delay to the top of your code.

You can see more detail on this FAQ