Send a dbus message to upower to refresh device state every 5 seconds.

PowerPoll.py

#!/usr/bin/python
# There is an issue with the power indicator on rMBP 13".
# upower doesn't indicate AC/Batt event change until it polls
# the device after 30 seconds of inactivity.
# Since 30 seconds is too long, using this script I force it 
# to refresh after 5 seconds by using the dbus. 
import os
import time

while True:
	os.system('dbus-send --print-reply \
	  --system \
	  --dest=org.freedesktop.UPower \
	  /org/freedesktop/UPower/devices/battery_BAT0 \
	  org.freedesktop.UPower.Device.Refresh')

	time.sleep(5)