Small script the gives you the battery percentage and colours it green when charging and red when discharging. Returns nothing if battery is 100%. I use it in my bash prompt and set the percentage a little lower.

batstat

#!/bin/bash                                                                                                                                                             

max_bat=`cat /sys/class/power_supply/BAT0/charge_full`
cur_bat=`cat /sys/class/power_supply/BAT0/charge_now`

per_bat=`echo "scale=0; $cur_bat*100/$max_bat" | bc`
status=`cat /sys/class/power_supply/BAT0/status | grep Discharging`

if [ $per_bat -le 100 ]; then
    echo -ne "$(tput sgr0)"
    if [ -z "$status" ];then
        echo -ne "$(tput setaf 2)"
    else
        echo -ne "$(tput setaf 1)"
    fi

    echo "${per_bat}%$(tput sgr0)"
fi