Seems like OZ drains my battery. Primarly I use Z to read books. While I was under pdaXrom, I can read 3-4 days and battery was still on ~70-80% (1-1.5h per day).
Now, 1-2 days, and 50% battery off!
ps: top doesn't show "idle" process, so it seems like nobody issue "idle" to CPU in OZ...