Lightening Bolt on my screen

I have a little lightening bolt in the top right corner of my screen. What does that mean?

I am using a experimental power supply, so it makes sense that it is related to that.

It indicates too low voltage.

Thanks for that. What a nuisance! Cheated again was I.

5V 3A says the power device. I thought it was cheap.

Where is that little lightening bolt documented? I will need the information as I extract my money back from the reprobates who sold me this little power pack!


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It’s here: FAQs - Raspberry Pi Documentation

If you have a multimeter, you could double-check the voltage reading on 5V and GND pins on the Raspberry Pi. (see for their location)

Also, the voltage gets a drop if you’re using a very long cable, shorter ones should be preferred.

This is due to a cheap power pack. I was hoping to be portable.
The warning is mostly there when I plug my Launchpad into the USB of the Pi. Want it to be portable, to survive being unplugged briefly.

It works fine with my Raspberry Pi branded supply.

My fault, should not have been tempted to buy a cheap power supply from a chain store, should have bought one directly from China…

Just a reminder that the official supply voltage spec is 5.1 Volts, typical backup battery packs and usb chargers output 5.0V creating a borderline situation without condidering the additional voltage loss in cheaper USB cables.
I typically see an intermittent lightning bolt running from a backup battery pack, I don’t recall if the 5V output of the USB connectors is the first thing to suffer, the 3.3V that runs most things had more margins.
There might be CPU clock throttling back in response to low voltage. (vaguely recall a note on that)