It's a common smartphone battery issue.. I haven't found any smartphone that can last more than a day with heavy usage. In my experience, iPhone 3GS has the worst battery. 1500mAh capacity is insufficient. but 2000mAh battery is too big. You have to live with that. The only few things you can do are turning the auto-brightness (if it has that function) and set the brightness to the lowest. turn off HSDPA connection, use 3G instead. turn off wifi etc