Battery issue with ios4.1

I downloaded 4.1 for my ipod touch 8gig and now my battery is losing 90% of its charge in 8 hours or so - in standby mode - overnight. I've turned off 'push' and fetch new data functions - even turned off wi-fy and it still is losing battery charge as if it's running a video! Anyone else with this problem? Suggestions?
PS when I first loaded 4.0 it did something similar for a couple of days ... then returned to normal - needing a charge every 3 days or so.