since ios 8.1.2 update the battery is very fast empty

Hi, i´m from gemany, hope my description could be understand?

Since the update 8.1.2 in December ´14 my iphone 5 battery is empty after 1,5- 2 days- the battery is new since oktober ´14, after changing the battery in oktober i´ve had a very good stand by time. I watched in the net for same problems but no real feedback about it by thinking that this is not only a problem by myself. Has anyone an idea about it?