Ok so this is what I got from Battery Health.
I have 16 tabs opened in Opera, but they're all light I think, just text and not some sort of fancy animation/flash/video battery draining.
Opera is already working with battery saving enabled.
In addition, I have iTuned running in background.
Half Display brightness.
I did also changed the display resolution, to improve battery life, as pointed out in this thread.
Even if the "current usage" show around 11 hours, Internet Browsing is 7 hours.
So I don't know if I have to feel satisfied or not...
Thoughts?