Consistently getting undervoltage reported

What is the problem?

My Octoprint consistently reports under voltage.

I appreciate that all Octoprint does is report the condition of the Pi and am looking for some pointers to track this problem down.

I'm now running a 17 hour print from SD card with Octoprint connected but just monitoring temperature.

What did you already try to solve it?

Upgraded the PSU to 5V 5A.
Disconnect the camera, filament runout sensor, PSU control.

Have you tried running in safe mode?


Did running in safe mode solve the problem?


Systeminfo Bundle

You can download this in OctoPrint's System Information dialog ... no bundle, no support!)


Additional information about your setup

Running latest release of Ocoprint with a Creality Sermoon D1. USB connection has the 5V connection taped.


Which generation of raspberry do you have?

A 5A powersupply should be good to run a raspi, assuming it delivers as labeled.
Is anything else connected to the raspi which could be drawing too much?
Like, the printer...

No, and the 5V feed from the USB lead is taped over. It's a mystery.

I've ordered another Pi 4 to eliminate that as the issue.

Thank you for your help.

are you sure the wire connecting the power supply and the Pi is sized adequately?
I had the same problem when I first started using Octopi and discovered the "charger cable" wire was to small and there was voltage drop between the power supply and the micro usb port. In my case, the wire was about 2 inches (50mm) long.
Replaced the wire and no problems since.

Yes, that was my first thought too.

I’m using a much thicker than normal cable with power cores that are larger than the date cores.

For power connection, the data lines are not used by USB up to version 2.

The Pi 3 has a self resetting fuse on the power input port. That has a certain inner resistance which results in a specific voltage drop..
Once this fuse was activated, it resets, but has a higher inner resistance afterwards and a higher voltage drop.
Some users (like me) avoid this by connecting the 5V directly to the 5V/GND pins of the GPIO header. If you do this, do it at your own risk.

This is the RasPi 3B+ power input schematic:

Thank you for that.

I’m using a Pi 4.

Is this the same?

No, Pi4 is a bit different:

If you such a power supply:


you can raise the output to 5.2V

What is the exact model of power supply you are using? Switch to a "raspberry pi" type power supply- e.g., if you're in the US, use a Canakit. What's the difference? It has a built-in cable (vs a 'modular' or 'phone charger' supply where you connect your own cable to it). The voltage regulation is to the connector itself- so you know you are getting 5v at the Pi, not simply 5v at the wall. Many power supplies struggle as demand increases above 0.5A.

You MIGHT be able to get away with your current power supply if you use a short cable, e.g., 1m or less. Some power supplies push 5.2v, which gives some room for voltage drop.

The Pi was built to a price point, so they don't add the extra circuitry that would get around this hassle, unfortunately. Perhaps the next version will do so, or will talk USB-PD to get around it.

Also don't forget a fatter USB cable doesn't mean the power conductors are any bigger :slight_smile: But ultimately you'll risk this problem any time you are using standalone cables, period.

Thank you for that.

I’m using a Pi 4.

Is this the same?

This is the PSU I'm using.

I going to solder leads directly to the board and bypass the USB C connector completely.

Thanks for all the help.

I'll post the solution - when I find it!

Does that supply have a make/model? The picture really doesn't tell anything other than it's hard wired.

This is the one I purchased.
Power supply.

the issue is more that although it reads the file and reports on the undervoltage it does not clear the notification. No matter what power supply i use, on a cold boot from power off it almost always (the pi) reports undervoltage detected and then says basically oops normal voltage detected but octoprint does not reflect the correction that Raspi makes in the info file.

which info file?

OctoPrint does change the icon shown depending on the undervoltage condition. If the icon is blinking, then there is undervoltage going on right now, if it is just solid then there was undervoltage. Hovering over the icon explains this.

If you want to monitor the raspi's state and have an mqtt broker installed somewhere there is a python script (2.7) to collect those data and report it via mqtt. health.service

Really useful when there are a few raspberries running, it helped me to identify power supply and temperature issues systematically and I generate nice graphs from it in connection with opeHAB/habpanel.

are you sure about that? :smiley:

Actually I think I should delete the post, since the info is not correct.
Glad you could set me straight! :smiley:
When I did mine, I was sure the prices were higher (Australian local suppliers).
In that case definitely the standard PSU is preferred! :smiley:

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"sudo nano" into your config.txt file, and insert the following


Then CTRL + X to exit, Y to save, then hit ENTER,


And a rather shady gentleman name of Robert passes himself off as being the brother of your father, although precisely how the, potentially fictitious, fact that Bob is your uncle RELATES to any of the previous guidance, I am not quite sure, but there we are.

Just FYI, btw, a little Brucey bonus I have added to that code ALSO addresses the THROTTLING issues that you would otherwise have come across once you HAD gotten past the undervoltage thing.

The THROTTLING issue prevents OctoPrint from installing or updating ANY plugins/extensions/etc, so it's worth fixing both together :slight_smile:

Let us know your progress

Since you didn't make it clear, I will - this is not the solution to the problems, it is just hiding them by disabling the warning. The equivalent of sticking a piece of paper over a hole in a wall, it just means the problem is no longer visible.

So please don't do this, and instead actually use a sufficient power supply for your Raspberry Pi.