[Nut-upsuser] How to change shutdown notification threshold on Fortron UPS Champs (blazer_usb)?

[Roger Price]

On Fri, 2 Sep 2022, Pavel Hofman wrote:

>> blazer_usb reports:
>>>> ups.model: WPHVT2K0
>>>> ups.productid: 5161

Clearly a bug in blazer_usb

>> If battery.charge.low is not available, perhaps it is possible to get the 
>> same effect by watching the voltage drop to a critical value.  This needs 
>> upssched and a custom upssched-cmd script.
>
> I see. IIUC since I basically want to "override" the LOWBATT event, not to 
> react to it, I will have to periodically parse upsc output and check for the 
> current battery.voltage level when OB. It means basically doing all the work 
> ups-monitor actually does, but with a different threshold (which I do not see 
> how to change in ups-monitor). Do I assume correctly I cannot force/script 
> ups-monitor to do that for me since it already has all the parsed data 
> available?
>
> Can I at least call some ups-monitor feature to start the controlled shutdown 
> on all the NUTS networked clients?

A lot of what you need is in chapter 7 of 
https://rogerprice.org/NUT/ConfigExamples.A5.pdf . Ignore all the stuff about 
heartbeat and timers.  The EXEC on lines 380 and 381 of upsmon.conf in figure 54 
will get you to line 398 in upssched.conf in figure 56.

At line 398, remove the lines "warning-timer" and "failure-timer", and add a 
line such as

   AT ONBATT <myups> EXECUTE watch-battery-charge

Change line 425 in upssched-cmd to VOLTAGE=$( upsc $UPS battery.voltage ) You 
may need to ensure that $VOLTAGE is an integer.

At line 428 in upssched-cmd replace the sections (heart-failure-timer), 
(two-minute-warning-timer) and (one-minute-warning-timer) with something like

   (watch-battery-charge)
      # Compare the $VOLTAGE with say 48 (Bash insists on integers)
      if [[ $VOLTAGE > 48 ]]; then continue;
      else MSG="Power failure shutdown: Calling upsmon -c fsd, $CHMSG"
           /usr/sbin/upsmon -c fsd
      fi ;;

Roger