Battery Full Xiaomi mi3 display

I got a xiaomi mi3 td a few weeks ago. Untill now its really awesome and in my opinion the worlds best phone ecspecially for this the price. But Im experiencing a really annoying issue. The battery drains much faster than it should (sometimes 800mW). It last only around 10 hours (at normal usage) other mi3's last around 2 days with same usage.
The screen is draining up to 70% of the battery even if its on low brightness!
After some time "googling" this issue, i found a thread where someone was experiencing the same issue with an s4, but nobody could help him...
i believe in you guys
So pls help
Proud owner of a Xiaomi MI3 TD