[arm-allstar] Notes on under voltage problem

[Jim Darrough]

My setup is with a Pi 3B, not B+. WHen I was using an Adafruit 2.4 amp 
power supply, no messages. Went back to a 1 amp power supply, messages 
came back. I don't think the b+ actually causes the problem, but I can 
see where it might draw more current. Voltage sag can occur (as Doug 
mentions) with current that comes close to maximum on any device.

Doug, is it possible the last updates have resulted in this happening? 
Maybe there was no monitoring until then?

73 Jim KI7AY


On 05/17/2018 12:43 AM, "Doug Crompton via arm-allstar" wrote:
> The Pi3B+ has a more advanced power and monitoring system. If you get a low
> voltage message it is probably worth looking into. The key here is under
> voltage and while this could be due to an under current power supply it
> does not mean that a "zillion" amp 5V power supply could not be under
> voltage. You need to check the voltage at the board with a good digital
> meter. Another important consideration is that the dynamic change in
> current of the board when heavily processing vs. idling can vary greatly.
> If the supply cannot handle these extremely fast current changes it could
> signal an under voltage condition. The wall wart you used to power your Pi2
> or Pi3B may not cut it for the 3B+ especially in turbo mode.
>
> I have had good success so far with wall warts BUT I consider myself lucky.
> I run 10+ Pi's with outlet strips full of wall warts. Ultimately this is
> probably not the way to go as besides the fact they can cause power
> problems they also emit a lot of RF noise. A better way would be to use the
> 12V to 5V 3A modules and run everything from a good 12V supply fusing the
> 12V input at each module. Here are a couple of examples. There are many to
> choose from on Ebay.
>
> https://www.ebay.com/p/Car-Buck-Converter-Step-down-Power-Supply-Voltage-Regulator-DC-12v-to-5v-3a-15w/19011441481
>
> https://www.ebay.com/itm/SUPERNIGHT-DC-DC-12V-24V-to-5V-3A-15W-Converter-Step-Down-Power-Regulator-Module-/392044239513
>
>
> *73 Doug*
>
> *WA3DSP*
>
> *http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*
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-- 
73 Jim
La ciruela de Panamá