Strange battery drain topic

Hi everyone,
my Note 3 has ever had a great battery life, but all of a sudden the voice "Android System" popped up to top in the battery list, followed by "Screen on" and "Android Operating System", and battery life is ridiculous (the screnshot I attach has 1h 11m of screen on only)
Any ideas?
I have stock Sammy ROM and no root.

Thanks a lot.