Nut upsuser - Apr 2025 - Log low input voltage

During periods of high power demand, I have noticed that the ups input
voltage drops.  I would like to log (to syslog) these low input voltage
events and can not see a NOTIiFYFLAG option.

Thank you,
-- 

*Bill Barnett*
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With NUT v2.8.3 (in release candidacy cycles now) there are new
notifications for OVER(load), TRIM and BOOST events - if raised by device
and driver.

Other than that, you might have to script something around `upsc` or use
the C/perl/python/... client bindings.

For regular logging specifically, see also `upslog` client - it got some
attention over the past couple of releases. But note it logs whatever data
points you select at intervals you specify, to a file or stdout. Perhaps
you can pipe it to a script that would look for your definition of low
voltage, might be more efficient than of spawning `upsc` for every lookup.

Hope this helps,
Jim Klimov


On Wed, Apr 16, 2025, 22:44 Bill Barnett via Nut-upsuser <
nut-upsuser at alioth-lists.debian.net> wrote:
> During periods of high power demand, I have noticed that the ups input
> voltage drops.  I would like to log (to syslog) these low input voltage
> events and can not see a NOTIiFYFLAG option.
>
> Thank you,
> --
>
> *Bill Barnett*
>
> _______________________________________________
> Nut-upsuser mailing list
> Nut-upsuser at alioth-lists.debian.net
> https://alioth-lists.debian.net/cgi-bin/mailman/listinfo/nut-upsuser
>
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Bill Barnett via Nut-upsuser <nut-upsuser at alioth-lists.debian.net>
writes:
> During periods of high power demand, I have noticed that the ups input
> voltage drops.  I would like to log (to syslog) these low input voltage
> events and can not see a NOTIiFYFLAG option.
I do not believe there is support for this, I don't think there should
be.  nut is supposed to watch for things that the ups considers
actionable and deal with them.  I think you are asking for noticing
variations that are within the UPS's tolerance of acceptable power, and
maybe even within specifications.

I don't mean that you shouldn't want to know; I want to know about this
too.  I have a python program that uses the pyNUT api and polls every
second, and then reports status over mqtt, once a minute, or more often
if something changed.  I ingest this into Home Assistant and get alerts.
But what the alert condition should be is hard to predict, and people
like us will want to tune it.

My nominal line voltage is 120, and typically it is 123-124.  A month or
so ago it changed to about 117, remained for half an hour, and returned.
This was far from the UPS transfer point, and entirely within
specifications, but I still found it interesting.  I asked a power
company line crew worker about this, and he said they had rerouted power
to my area from a different distribution feeder (to denergize part of
the other feeder to do some maintenance), resulting in that other feeder
having much higher load than usual.


I am guessing by high power demand you mean roughly/broadly among all
who are connected to your substation.

If you are finding that the ups input voltage drops because of load that
is connected to the UPS, you might want to check your wiring.  Something
like this would help -- but don't test your UPS's voltage drop with a
20A load!


  https://www.kleintools.com/catalog/electrical-testers/circuit-analyzer