Under-voltage message won't go away

[SkalTura]

I know that there are many topics already about this, but all I tried failed for me.
The power supply I'm using for my RPi3B+ is 5V, 3A. That should be enough right ?
But ever so often the lightning bolt and the message "Under-voltage" show up...

So, I tried blocking the message and the bolt using several different options in the "cmdline.txt" and "config.txt" files.
The lightning bolt is now no longer showing, but the annoying message still is...

In the config.txt file I added avoid_warnings=1
In the cmdline.txt file I changed console=tty1 to tty3, and loglevel=0 to 3

Running RetroPie 4.6 by the way...

Please help me to disable this undervoltage message...
Thank you

[trejan]

The power supply I'm using for my RPi3B+ is 5V, 3A. That should be enough right ?

The quality of the power supply and the cable also matters. Some cables have puny wires inside because it is cheaper which results in a large voltage drop and the undervoltage warning showing.

[drgeoff]

Fix the primary problem, not the secondary effects.

Either your power supply or the cable between it and RPi is inadequate. Or both.

[SkalTura]

Tried connecting it directly through the I/O, using a professional adjustable power supply limited at 3,5A (it's a calibrated PSU I borrowed from work), and it shows some peeks of 2,7A, but mostly stable at 2,3A. Still the message appears sometimes...
So I would rather just block the message, because it seems to me that the power sensing part of the Pi is just not that accurate.

[Brandon92]

Tried connecting it directly through the I/O, using a professional adjustable power supply limited at 3,5A (it's a calibrated PSU I borrowed from work), and it shows some peeks of 2,7A, but mostly stable at 2,3A. Still the message appears sometimes...
So I would rather just block the message, because it seems to me that the power sensing part of the Pi is just not that accurate.

What for size wires did you use here. Because you can use a 5V 10A power supply and got the same message when you use a the thin wire. The power supply gives 5V but at the end of your wire it is for example 4,7V.

[SkalTura]

What for size wires did you use here. Because you can use a 5V 10A power supply and got the same message when you use a the thin wire. The power supply gives 5V but at the end of your wire it is for example 4,7V.

I used 1mm wire (think that is 17 or 18 awg?).
I work in electronics for more then 25 years, so I know that the resistance of the wire plays a big part in the output of a PSU.
Trust me... the power going in the Pi is 5V spot on (says so on the PSU, and measured it also at full load with a multimeter), and as I said before, the current peaks at 2,7A, so I don't understand why the message keeps popping up.

So I want to block it, since I'm positive my power supply is correct, and the Pi is wrong.

[trejan]

I would normally suggest measuring at the GPIO pins but you said you've fed in 5V there already.

So I want to block it, since I'm positive my power supply is correct, and the Pi is wrong.

The voltage warning is reliable so it would be unusual if it is a fault with the Pi. For your Pi 3B+, the voltage check is being done by the MxL7704 PMIC. It will set an undervoltage flag if the input voltage dips below 4.63V even for a very short period of time.

If you really want to ignore those messages then blacklist the raspberrypi_hwmon module. It is the kernel module responsible for polling the firmware to see if the undervoltage flag is set.

[FTrevorGowen]

..
I used 1mm wire (think that is 17 or 18 awg?).
I work in electronics for more then 25 years, so I know that the resistance of the wire plays a big part in the output of a PSU.
Trust me... the power going in the Pi is 5V spot on (says so on the PSU, and measured it also at full load with a multimeter)
...

The PMIC's undervoltage sense will trigger on voltage dips (due to current surges) only observable with an oscilloscope (or similar) - a multimeter will not sample fast enough (typically about once every 250ms eg. see this spec: https://www.cpmspectrepi.uk/raspberry_p ... 000zc.html )
Trev.

[jamesh]

Measure the voltage on the GPIO pins with a scope. That's the only way to be sure*.





* Apart from nuking from orbit, obviously.

[bensimmo]

That's a lot of current for normal RetroPi setup, what else are you attaching to it to increase the current load up to 2.3A?
These thing idle run much less than.
Sounds like some external motor triggering cashing a sudden drop the PSU cannot respond to.

[SkalTura]

So, measured with a scope... Still 5V, no drops...
The 2,7A peaks seam to appear when I run certain Mame ROM's.
All other operation of the Pi is between 2.0 and 2.5A.

Main question still unanswered though.... Can you permanently block this message of not ?

[rpiMike]

I thought the voltage should ideally be close to 5.1V?

[trejan]

Main question still unanswered though.... Can you permanently block this message of not ?

I told you how above.

[Brandon92]

What for size wires did you use here. Because you can use a 5V 10A power supply and got the same message when you use a the thin wire. The power supply gives 5V but at the end of your wire it is for example 4,7V.

I used 1mm wire (think that is 17 or 18 awg?).
I work in electronics for more then 25 years, so I know that the resistance of the wire plays a big part in the output of a PSU.
Trust me... the power going in the Pi is 5V spot on (says so on the PSU, and measured it also at full load with a multimeter), and as I said before, the current peaks at 2,7A, so I don't understand why the message keeps popping up.

So I want to block it, since I'm positive my power supply is correct, and the Pi is wrong.

Okay, not all the people know that so I asked it to make sure. But it is indeed a strange that you will have that message.

Do you have a additional SD where you can install a fresh image on. Maybe there is a something wrong in your software? Maybe good to try, but I'm not sure if it will help.

[jamesh]

So, measured with a scope... Still 5V, no drops...
The 2,7A peaks seam to appear when I run certain Mame ROM's.
All other operation of the Pi is between 2.0 and 2.5A.

Main question still unanswered though.... Can you permanently block this message of not ?

Stranger and stranger. Running idle, just the desktop, the current draw should be less than 1A. Hitting 2.7A just running software is WAY more than I would expect. You'#d need to have loads of stuff plugged in to the USB to get anywhere near that. So, do you have anything plugged in that could be using so much power?

The voltage warning kicks off at 4.65v. Will never appear unless it drops below that. Unless there is a HW fault on the PI.

[LTolledo]

show us an image of your setup.... am getting headaches trying to imagine it....