WiFi - off
3G - off
Wallpaper - static black
Mobile was fully charged by 7am, day 1.
day 1, 9pm - 80% charge left
day 2, 11pm - 65% charge left
day 3, 2pm - 50% charge left
day 3, 5pm (after 50mts call, connection to WiFi few times) - 20% charge left
day 3, 8pm (after shooting 2 mts video) - 15% charge left
Recharged the battery again at 9pm.
Overall result: Managed to run Galaxy S2 for 3 days in a minimalist mode.