I have RPI 4b as Octoprint server and it's running on updated Octoprint 1.10.3. when I powered up RPI and printer, I noticed warning message stating that "Undervolt Detected". It's the first time I see it. I have RPI 20 watts, 4amp power jack with switch button on wire and USB C on end. This jack provide more than enough power and it's not old. I never encountered "Undervolt Detected" on previous Octoprint version before update. I wonder if you can just tweak your software to "undervolt" detection so it won't pop . Even with that popped up on upper right corner of Octoprint window, I left printer running all night and never was the issue. I believe software is popping up false message that it's underpowered. Can you fix that issue?
Thankyou!!
Hello @mattdebauge !
When you need help, then use the subforum Get Help.
Without the requested information there, it's hard to help.
This is no issue. This is a feature for a reason.
What do you have as PSU for the Pi?
In most cases, this happens due to a short drop caused by a load change. The cause is often too thin copper wires or transition resistances in plug contacts.
The safest variant is an operation with a stepdown which is connected to the pin header. It is also possible to fix this with an ELKO e.g. 100uF/16V also connected to the pinheader.
I checked the PSU and it's 3 Amp power supply (5v 3,000 ma). As for Linuxpaul comment, load drop cause by too thin copper wire. I agreed. I will add capacitor to smooth out voltage drops due to loads. It make alot of sense that wires are too thin. (it's like skinny water pipe can't keep up water flow to shower, washing machine ect.). Thankyou for the advice!!
In this case it's not the current that count, it's the tension.
Raspberry Pi org recommends 5.1 V for the PIs
5,1V is not a feature, it points out the bug. If you take a look to the Pi4 board s. spec, you'll find 5V/3A for the board..
Depending the spec, the flag occours, tf the voltage drops below 4.75V. For this reason, the seller of a 5.1 solution expect a drop of ~0.3V.
I'm fine with a 5V/3A stepdown with low impendanz and fine wires. Currently I'm running with 4.95V at one of my pi 4 and non of my 12 Pis are powead by a 5.1V bullshit hardware.
I think there is a reason why 5.1V is recommended.
Be happy if it works for you with less. But do not assume it will do everywhere.
I think this kind of expression is not welcome here.
Yes, the reason is earning money. Copper is expensive, so it is possible to save money by increasing the impedance by saving it and move to 5.1V to compensate that. Good advertising does the rest to force the people to buy THEIR power supply.
The ideal power supply has an internal resistance of 0 Ohm and the greater the internal resistance, the worse the power supply.
For me, any 5V 3A power supply with a corresponding cable works.
Yes, I agree with you that some power supply have thin wires (pretty much like cheap phone charger and wires not providing enough amperage even it states and charging time on phone is longer.). I think that why I bought it off from Ebay. Because it have built in power switch on wire so I can shut off RPI. Thinner copper, power straining thru wires. I can afford RPI flagship power supply, I was just in hurry grabbing cheap one LOL. I think power supply is getting bit weak after lot of use which is why power dips.