[Nut-upsuser] Where are usbhid-ups driver parameters defined - and what do some of them mean?

[Rob MacGregor]

On Fri, May 22, 2009 at 08:41, Richard Chapman <rchapman at aardvark.com.au> wrote:
> I am using the usbhid-ups driver with a Belkin UPS.
> upsc shows several parameters which I would like to both understand and
> probably change. In particular the following part of upsc output:
>
> battery.charge.low: 30
> battery.charge.warning: 30
> battery.runtime: 120
>
> My questions are:
>
> 1) What is the difference between battery.charge.low and
> battery.charge.warning? I presume these are % thresholdsWhich of these
> triggers the low battery event?
> 2) Is there some way to change these? 30% charge seems to me to be sailing a
> little close to the wind. As the battery ages - I'm sure the UPS will cut
> out long before "zero" is reached. Also - if it comes back up with  < 30%
> charge - and another power fail occurs soon after - that is not good. Are
> these set i the source code - or is there another config file somewhere.
> upsrw doesn't appear to be able to change these.
> 3) What exactly is battery.runtime.

This answer in the list archive
(http://osdir.com/ml/monitoring.nut.user/2007-12/msg00014.html) covers
at least some of your questions.  This
(http://www.mscs.dal.ca/~selinger/ups/backups.html) slightly old page
describes the variables you list.

In short, not all UPS units support changing the low battery level and
the battery.runtime is the runtime in seconds of your UPS on
batteries.  The link says it's without load, but I have a unit that
changes that reported value based upon load.  Either way, 120 seconds
is not enough time to shut down.  Either your UPS is under specified
(ie the load is high) or the batteries are very, very, old.

-- 
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Rob MacGregor
      Whoever fights monsters should see to it that in the process he
        doesn't become a monster.                  Friedrich Nietzsche