Resolved - RPi Under-voltage Warning At Any Time

General Discussion
1

Basic Information:

Printer Model: Ender 3 V2
MCU / Printerboard: Stock Creality 4.2.2 + Raspberry Pi 3B
klippy.log (507.1 KB)

(This issue has been resolved)

My raspberry pi 3b keeps getting an under-voltage warning, even when I’m just homing the printer. The lights on the Pi also blink at random intervals when the warning comes on.

The Pi is powered by a buck converter attached to the stock Ender 3V2 24v Power supply. The buck converter is set to lower the voltage to 5.25v, the maximum recommended voltage for a Pi. Along with running Mainsail, the Pi also has a 480p 15fps USB webcam and is hooked up to an Obico server to monitor remotely. The weirdest part is after monitoring the voltage constantly after hooking up my multimeter, the buck converter is constantly delivering 5.25 even while there is still an active under-voltage warning (as shown in the photos). Also, I did confirm that there is no warning when powering the Pi with a 5V CanaKit wall power adapter.

VideoCapture_20230122-161729
VideoCapture_20230122-1617291080×1920 142 KB

I have googled and looked through many forums, but I don’t see anyone with a similar problem. Does anyone have a solution for this? If not I think I’ll have to stick with powering the Pi separate from the printer.

Thanks in advance.

(This issue has been resolved)

2

What is the current output of the buck converter?

For an rPi 3 B, it is recommended that you provide 3.5A of current and for the rPi 4 B, the recommended current source is 2A. In both these cases, this is with no external load(s) - if you attach a display to the rPi, then you should add 2A to the recommended values. Most references I see state that you should supply 5A of current to an rPi.

In your picture, you have a USB line going to what looks like your controller (which shouldn’t draw any current) and one going somewhere else (which may). I presume the fan load is pretty negligible.

Out of convenience and lack of wall plugs, I attached one of my rPI 4s to the USB port of a Mac Mini for a while and I continual under voltage event notifications although I never saw an operational issue.

3

Thanks so much for the input! The buck converter specs online only rate for a max of 3A which is where i think i found the problem. Thanks for the help!

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