Pi Undervoltage/power issues: I had a strange lightning bolt/temperature symbol with an exclamation mark popup in my navbar, what does that mean?

Starting with OctoPrint 1.3.10, the bundled "Pi Support Plugin" (only active when running on a Raspbery Pi) will regularly check if your Pi has detected any underlying issues via vcgencmd get_throttled.

This command can detect whether your Pi is currently throttled, or has been in the past, either due to undervoltage or overheating.

The Pi Support Plugin evaluates this information and displays corresponding icons in your navbar in case such a situation is detected:


In the above example, the Pi has detected both undervoltage and over heating. Clicking on the symbols will lead you to this FAQ entry. Hovering over the symbols will give you further information:


In this popover, detected issues will be highlighted in red (and - if a current issue - also blink just like in the navbar).

Your Pi is reporting undervoltage

You need to change the way you are powering it. Do not use some cheap phone charger you still have lying around, use a proper power supply that provides 5V and at least 2A current reliably. Also make sure that the cable from your power supply to the Pi is up to the task - there are cables out there that are not allowing needed voltage to actually arrive at your Pi due to too high internal resistance. Use a good quality thick cable, not some flimsy thing you still had somewhere in a drawer.

If in doubt, the official Raspberry Pi power supplies are a good option.

There's also the possibility of your printer sucking power from your Pi:

Your Pi is reporting it's overheating

You need to provide it with better cooling. Make sure that air can circulate freely around it, and possibly add some cooling sinks to the chips.

In case of any reported issue

If you get a report on any current issue or any issue observed since boot up, be sure to look into them - the Raspberry Pi is known to behave erratically especially in undervoltage situations and cause all kinds of issues, including communication issues with your 3d printer that can and will ruin your prints. If things are set up well, you really should never see these symbols pop up. If they pop up, it means there is a problem:

Triumphantly disabling the check does not solve the problem. Don't be like Homer.


Hi Foosel. What are the thresholds considered as overheating and undervoltage? My Pi sometimes get close to 70 degrees Celsius, and I get no messages about overheating. I'm already trying to make it run cooler, but in this meantime I'd like to know if is still safe.


She's simply reporting back what Raspbian's vcgencmd get_throttled reports.

voltage < 4.6
temperature > 80 ARM frequency capped
temperature > 85 throttled

Seventy is still okay.

Seventy is still ok, but I think it maybe compromise memory card life. I've read that somewhere. Tks.

You could add a USB thumbdrive to your Raspberry and push the ext4 partition over to that. So basically, the microSD only needs the firmware on the boot partition and everything else to include the swap space is on the USB.

Technically, one can "magic" the Raspberry Pi to bootup from USB (foregoing the microSD completely). Strangely, though, once you toggle this setting you can NEVER toggle it back.


Thanks for this feature.. I just found out the standby line on my atx power supply isn't adequate :frowning:

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I have a raspi 3 B+ and a powerplug for the raspi with 5V/3A.
But sometimes the octopi web app show me the blitz and the warning, that I have to look after the powerunit.
So, what can I do? The powerunit should have enough power for the raspi.

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What is your power supply? What is the USB cable you use on it? I'm going to merge this with the megathread on the topic.

It's a 5V/3A Micro USB Netzteil ON/OFF Schalter Ladegerät Adapter für Raspberry Pi DE

Can you provide a link to the exact model?

5V/3A Micro USB Netzteil ON/OFF Schalter Ladegerät Adapter für Raspberry Pi DE

it looks like it should be okay, but it's clearly not supplying the stated voltage to the Pi. That's not surprising, a lot of power supplies don't actually provide power without dropping the voltage.

This should be an official power supply, from a German source. There might be more suppliers but I could determine this one was official.

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...unless of course the Pi is overburdened with hats.

...or it's sinking power to the printer controller board.

...or it's driving a strip of LEDs, a camera and any other unnamed devices which haven't been mentioned.

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With the raspberry pi there is only a camera (pi camera) and the 3D printer connected.
But at the USB cable to the 3D printer the pin +5V is isolated.
And that configuration can cause the undervoltage sign?

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You could always disconnect the serial cable and see if OctoPrint continues to report an undervoltage condition. If it still does, then I'd power if off, disconnect the camera and boot it back up. If the undervoltage condition continues with a naked Pi with no printer connection then that's a pretty good indication that either your power adapter is faulty or perhaps your power outlet isn't providing the minimum voltage.

Of course, I'm the type who would measure the wall outlet, the power coming out of the UPS, the power coming out of the power adapter, the power of the 5V line on the Pi before/after connecting things. 4.64VDC is the threshold, in case you were wondering.

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What is the problem?
lightning bolt always there
What did you already try to solve it?
test multiple USB ports and cables

I have used multiple different Pi's, all kinda of power supplies, blocks, cables. unplugged everything including the printer, I can't get rid of the low power lighting bolt. Tested USB and it's a constant 5.2v which should be way more than enough? can we make it actually tell us what it's reading for power? I believe it's reading incorrectly or something. ??

I know there are other threads/topics on this but being new here for some reason it wouldn't let me post to them.

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Read the original post here for a description of how the status bar icon behaves. Upon clicking that icon it tells you more information.

The serial cable type (unless it's super-long) is probably not the issue unless your printer board is sinking power from the Raspberry but you've indicated that you unplugged the printer.

  • You didn't mention which Raspberry this is. The faster it's clocked, the more power it consumes and the 3B+ seems to be the hungriest in this regard.
  • Many manufacturers lie about the specifications of their power adapters (in this case) or simply do a bad job designing them and don't actually know what they're doing. So it's important to test the power adapter under a comparable load. Imagine the motor's speed difference both before/after then adding a propeller to the shaft; the difference is the load.
  • Is there an LCD/TFT panel on this or a webcam or a USB thumbdrive? Those all require power.
  • If you have a multimeter, it's worth plugging it into the wall outlet itself to verify that the power is stable. I always plug mine into a high-quality UPS which does a good job of regulating the 115VAC that goes into the power adapter.
  • Try a different wall outlet in a different room. Perhaps it's the connections themselves or the wiring.
  • If you can remote into the Pi then you could run commands like those described here.
  • Similarly, you could run dmesg | grep voltage.

If ultimately you can't resolve this, see if you can find a 3A 5V power adapter.

@Thomllama, do you have any plugins installed that also use the lightning bolt icon (ie any of my power plug related plugins)? There was some confusion early on with the Undervoltage/power icons looking similar and the pi support plugin ended up switching their icon to the one shown in the first post.

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Read this and many, many other post, forums, tweets and such. All say the same thing, under power, but tested and if anything, I’m supplying too much power, 5.2v at 2.8A is what my meter says. Now, why aren’t we using the actual power supply port instead of USB? Wouldn’t that be a better, more stable and reliable input? Something I’m missing about using it?