Install and enable the upsmon driver from nut

# install the full nut package
pkg install nut
# Tell sysrc to enable upsmon
sysrc nut_upsmon_enable="YES"
# verify you have a connection to the master
upsc ups1@192.168.1.100

Configure two files, both in /usr/local/etc/nut

nut.conf

# this will not do anything except communicate with the master
# to get the status
MODE=netclient

<file autoconf upsmon.conf> MINSUPPLIES 1 SHUTDOWNCMD “/sbin/poweroff” POLLFREQ 5 POLLFREQALERT 5 HOSTSYNC 15 DEADTIME 15 POWERDOWNFLAG “/etc/killpower” OFFDURATION 30 RBWARNTIME 43200 NOCOMMWARNTIME 300 FINALDELAY 5 # this is what we're monitoring MONITOR ups1@192.168.1.100:3493 1 upsmon mypassword slave </conf>

Start the service

service nut_upsmon start

• https://dan.langille.org/2020/09/07/monitoring-your-ups-using-nut-on-freebsd/