Eaton 3S 550 and Raspberry Pi

Briefly about the setup: Eaton 3S 550 powers a constantly running Raspberry Pi (RPi), wireless router, ADSL modem, cordless phone, wireless energy monitor (Eliq) and home automation device (Tellstick Net). All in all they are 10% of the UPS capacity which gives me about 30 minutes safety window before the RPi will shut down (shut down is triggered when battery is below 20%).

The Raspberry is running latest Raspbian and monitors the UPS using Network UPS Tools (NUT) which can power off the computer, send notifications etc. I have set up script to log the events and get an SMS on power failures (using Android phone and SMS Gateway).

Below is a screenshot from the NUT monitor GUI and results from a test run of the setup. I have manually started a bash script to collect the battery status by pooling every 15 seconds with "upsc eaton3s@localhost | grep battery.charge:"