[Nut-upsuser] Can't get CyberPower UPS to work with Raspberry Pi 4

Charles Lepple clepple at gmail.com
Sat Oct 31 15:55:54 GMT 2020

On Oct 30, 2020, at 12:22 AM, Gene Heskett <gheskett at shentel.net> wrote:
> On Thursday 29 October 2020 22:12:00 Charles Lepple wrote:
>> On Oct 28, 2020, at 9:56 PM, Gene Heskett <gheskett at shentel.net> wrote:
>>> Which looks very incomplete to me.  OTOH, its not a very big UPS but
>>> neither is the pi.  I have tested that, and it shuts off long before
>>> it outouts a LB signal.
>> Which part looks incomplete, the variables or the commands?
> Commands Charles.  Since the pi is a very low drain bit of kit, I 
> expected to be able to lengthen the shutdown delay, to at least use 50% 
> of the battery, which should be several hours but its stuck at 2 
> minutes. Unreal, but it is what it is.

This is going to sound a bit picky, but to map what you're describing to what is implemented in NUT, "lengthen the shutdown delay" (with a driver that works 100% as expected with that UPS) you'd want to change a R/W variable, which is separate from the list of instant commands.

(There is another "shutdown delay" - the time between when NUT signals the UPS to turn off, and when the relay actually goes "clunk". That would be "ups.delay.shutdown", but from the context, it sounds like you are concerned about lengthening the time between when the power fails and when the UPS says "the battery is low". A USB HID UPS typically measures it the other way: the battery is low (LB flag is set) when either:

* the charge is below a certain percentage (battery.charge.low)

* or the runtime is below a certain number of seconds (battery.runtime.low) - though for a CyberPower UPS, you generally have to round up any time-related values to the next larger multiple of 60 seconds.

(Of course, those are both estimates, but ideally, after a battery test, those estimates are close to reality.)

So if the UPS is setting the "LB" flag too early for your needs, you have a few options. As long as the UPS isn't turning off on its own (that is, NUT is telling it to turn off), and the reported charge or runtime values are reliable, you can tell NUT to use its own thresholds for shutdown:

"ignorelb" under UPS Fields: https://networkupstools.org/docs/man/ups.conf.html#_ups_fields

>> Even the larger UPSes tend to return a lot of read-only values, and
>> only provide a few knobs for shutdown-related settings.
> So I note running those cmds on this 1500wa APC under this desk. 
> Disappointing...

The APC protocol situation is a different rant entirely...

> Take care now.

You, too!

> Cheers, Gene Heskett
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
> Genes Web page <http://geneslinuxbox.net:6309/gene>
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