General discussion • Strange behaviour when powering RPi5 from GPIO

Hello forum, I am seeing some very strange behaviour when trying to power a Raspberry Pi 5 through the GPIO.

The board is an out of the box RPi5 with 8GB RAM and booting from a freshly flashed SanDisk 16GB card.

Booting when powered over USB works fine.

I have appended the following to the end of /boot/firmware/config.txt:
usb_max_current_enable=1

and this after running sudo -E rpi-eeprom-config --edit:
PSU_MAX_CURRENT=5000


Based on pinout here:


I am connecting pins:
2 -> 5V (sometimes to test)
4 -> 5V
6 -> ground
14 -> ground (sometimes to test)


Now, I am using the LABPS3005DN power supply by Velleman:
https://www.velleman.eu/products/view/?id=439082

When setting it to 5V and a max of 5A, I get the red STAT LED.
Tried 4.9 to 5.1 Volts and also tried turning on the power supply first and then connecting, no luck.
I also tried pressing the power button, the LED turns green for a second or so and then turns back to red.


Then I tried putting a Traco Power TEN40-2411N before the RPi5 and feeding it 19 Volts from the power supply (its input is 18-36 Volts). Its open circuit output is around 4.98V. Powering the RPi5 with the output from the TEN40-2411N makes it boot immediately, without pressing the power button.

What is happening here? Are the volts produced by the TEN40-2411N tastier than the volts produced by the LABPS3005DN?

Statistics: Posted by armadillo — Fri Jan 10, 2025 2:01 pm — Replies 2 — Views 106

---