Pi V3 - occasional switch to battery power and back to Pi Power

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RDK
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Pi V3 - occasional switch to battery power and back to Pi Power

Post by RDK » Mon Aug 06, 2018 6:39 am

I'm running a Pi v3 / Stretch. I have a UPS PIco HV3.0A with firmware 38. For the most part it and the associated Python program are running fine.

However, randomly it will start making a beep sequence noise. That may continue for several minutes and then stop. The Pi is not rebooting nor has the Python program ended or thrown an error.

A couple days ago I was able to run the PIco status program during one of these episodes and noticed that it seemed to be oscillating between "Powering Mode.........: RPi POWERED" and " Powering Mode.........: Battery POWERED" with each beep sequence. As far as I can tell the rest of the data from the Status script looks normal
***********************************
UPS PIco HV3.0A Status
***********************************

UPS PIco Firmware.....: 38
UPS PIco Bootloader...: 53
UPS PIco PCB Version..: 41
UPS PIco BAT Version..: LiPO (ASCII: S)
UPS PIco BAT Runtime..: 1 MIN
UPS PIco r232 State...: OFF

Powering Mode.........: RPi POWERED
BAT Percentage........: 106.666666667 %
BAT Voltage...........: 4.2 V
RPi Voltage...........: 4.9 V
NTC1 Temperature......: 58 C
TO-92 Temperature.....: 23 C
Extended Voltage......: 0.0 V
A/D2 Voltage..........: 0.0 V

PIco FAN Mode.........: ERROR
PIco FAN State........: OFF
PIco FAN Speed........: 320.0 RPM
I also swapped out the power supply during that episode without effect. There are two other Pi's on the same power strip and same APC backup power system and they did not exhibit any issues.

Any ideas about this issue?.....RDK

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Jake
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Re: Pi V3 - occasional switch to battery power and back to Pi Power

Post by Jake » Mon Aug 06, 2018 8:48 am

Hi,

Sounds like the PIco is detecting a voltage drop below the threshold due to insufficient power, initiating battery power, this probably causes the available voltage to increase slightly back above the threshold, so the PIco flips back to RPi power, which then drops the voltage slightly, so it switches back to battery power, and round and round we go :D

^^ I would suggest therefore that the voltage available on your power strip is not sufficient. Electronics built to tolerances, so maybe this is a particularly juicy Pi coupled with a particularly sensitive PIco.

If you connect this PIco & Pi to a known stable standalone power source, and it doesn't exhibit the above behaviour, then your power supply is not sufficient.

-- Jake
Forum Administrator & Technical Support

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RDK
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Re: Pi V3 - occasional switch to battery power and back to Pi Power

Post by RDK » Mon Aug 06, 2018 11:45 am

OK, I'll look into this. My office PC and file server are on one APC UPS power backup unit and the routers, PI's and switches are on another. Thus the Pi's with their own PIco UPS's are theoretically double protected. I'll move that Pi to a different circuit which is not coming off of one of the APC units.

Is there a way to silence the beep sequence triggred by the change from POWERED or RPI or vice-versa?

Thanks for the reply....RDK

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Jake
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Re: Pi V3 - occasional switch to battery power and back to Pi Power

Post by Jake » Mon Aug 06, 2018 2:01 pm

It does sound like that's the issue!

Buzzer function, please check the manual here:

https://drive.google.com/file/d/1GT3Q0W ... mZwrixBxI/

Page 97

sudo i2cset -y 1 0x6D 0x00

Should disable the sounder. Or de-solder it :D

-- Jake
Forum Administrator & Technical Support

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