Blackberry Battery Drain and Theme

[MiataMike]

Blackberry 9630 Tour
Verizon provider
OS 5.0.0.732

Is there a reason some themes seem to have more than double the battery drain than other themes? I can go all day (12 plus hours) running say BlackberryOS v3 theme, making sales calls, taking pictures, surfing net etc. Last few days I have tried Foreberry from Socksinsideout, and also iBerry4. Today I made fewer than half the phone calls I normally make and had no less than 30 min of websurf, took zero pictures and battery was dead in about 8 hours.

SO QUESTION IS..... How does the Theme affect battery life so drastically? If it matters, was NOT running bluetooth. Themes all used same wallpaper, and phone was in same physical location (so same radio signal etc), phone was in magnet (sleepmode) holster.....
Has anyone compiled a list of "battery friendly" themes?