APC UPS Setup and Calibration

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Note: This is for a single host setup if you want to share the ups see https://herold.space/share-ups-using-nut-on-a-raspberry-pi

UPS Setup

Install the apcupsd daemon and configure it.

apt install apcupsd

sed -i "s/\/dev\/ttyS0/\/dev\/usb\/hiddev0/g" /etc/apcupsd/apcupsd.conf

sed -i "s/BATTERYLEVEL 5/BATTERYLEVEL 20/g" /etc/apcupsd/apcupsd.conf
sed -i "s/MINUTES 3/MINUTES 7/g" /etc/apcupsd/apcupsd.conf

systemctl restart apcupsd
apcaccess status

UPS Calibration

Lead-acid batteries lose capacity over time and after 3 to 5 years they need to be replaced. Therefore it’s important to calibrate them once a year.

Before you start make sure the battery is charged at 100% and has a load of at least 30% attached. Also write down the value of “TIMELEFT”

apcaccess | grep -E "BCHARGE|LOADPCT|TIMELEFT"

First stop the apcupsd daemon and then run apctest.

systemctl stop apcupsd

apctest

1)  Test kill UPS power
2)  Perform self-test
3)  Read last self-test result
4)  View/Change battery date
5)  View manufacturing date
6)  View/Change alarm behavior
7)  View/Change sensitivity
8)  View/Change low transfer voltage
9)  View/Change high transfer voltage
10) Perform battery calibration
11) Test alarm
12) View/Change self-test interval
 Q) Quit

Select entry 10 and monitor the calibration process.

It will drain the battery to 25% and afterwards charge it back up.

Once it’s done start apcupsd again and check the new “TIMELEFT” value.

systemctl start apcupsd

apcaccess | grep -E "TIMELEFT"

Make sure it’s over 10 minutes otherwise replace the battery.

Calibration Reminder

Replace user@example.com with your email.

It will remind you once a year to do calibration.

cat << 'EOF' > /etc/cron.daily/batterycalibrationreminder
#!/bin/bash
EMAIL="user@example.com"
if [[ `/usr/sbin/apcaccess | grep BATTDATE | grep "$(date +%m-%d)"` ]]; then
    /usr/sbin/apcaccess | mail -s "battery due for calibration" $EMAIL
fi
EOF

chmod +x /etc/cron.daily/batterycalibrationreminder