Firstly, I think the Epic is suffering similar issues as the EVO did initially, where the radios aren't tweaked well enough, and are actually running alongside one another.
At times on my phone, Ive gotten the 3G icon and 4G icon's running concurrently, this seems to absolutely destroy our phones..even in sleep or standby mode.
I spent yesterday breaking down the phone, playing with different settings and what not..
This is my usage from lastnight, till this morn:
As of 11am, Im just down to 66% Battery..
Imo, its the background sync(accounts/sync), combined with the terrible 4G and 3G radio's, that are killing our batteries.
Ive disabled 4G, enabled 3G with SwitchPro widget, and disabled the background tasks.. and I get a 1% drain over 2 hours off the charger.. I haven't charged it yet, but i would surmise the charge rate would improve as well.. as its no longer fighting to swim upstream.
This isnt a solution of any sort.. just an observation.