/usr/lib/systemd/system-sleep/battery-monitor

battery-monitor

#!/bin/bash
# battery monitor systemd suspend/resume hook

LOGFILE=/var/log/battery.csv
KERNEL=$(uname -r)
BIOS=$(dmidecode -s bios-version)

log() {
    cd /sys/class/power_supply

    for power_supply in BAT*/; do
        if [ -f `pwd`/$power_supply/energy_full ] && [ -f `pwd`/$power_supply/energy_now ]; then
            ENERGY_FULL=`cat $power_supply/energy_full`
            ENERGY_NOW=`cat $power_supply/energy_now`
            TIME=`date "+%s"`

            echo \"$BIOS\",\"$KERNEL\",\"$1\",\"$power_supply\",\"$ENERGY_FULL\",\"$ENERGY_NOW\",\"$TIME\" >> $LOGFILE
        fi
    done
}

case $1 in
    pre)  log $2 ;; # "suspend", "hibernate", "hybrid-sleep", or "suspend-then-hibernate"
    post) log resume  ;;
esac