I use screebl (screen blank ) and have seen a noticeable difference in battery longevity. This way i can keep my device screen timeout to 15 seconds. I
wish there was a 5-7 seconds setting and I would be in heaven. Did I mention its FREE
or if you prefer the Pro version offers locale support for $1.99
'Screebl is an application that controls power saving features of your phone based on orientation. Never have the screen blank again while using your phone, and SAVE BATTERY at the same time. It's possible with Screebl!'
Screebl Lite v1.9.0 Application for Android | Tools
I am telling you once you get used to the ability of screebl you cant live without it. After I flash a new rom before I have it reinstalled and enabled I go nuts with the screen timing out. Screebl stops the black outs
and saves battery too!