Since updating to Cyan, my L920 has gone from 10-12 hours between charges to 3-4 hours with minimal use. If I actually use the phone, it'll drain out in less than two hours. I'm constantly going from one charger to another to keep it functioning. I've also noticed that I have to use a wall charger or wireless charging plate to charge it. If I use USB, the drainage rate is equal to the charge rate so it never charges, just sits at whatever level it is at whenever I plug it in! This is becoming a huge pain in the neck!
ETA: I think I found my problem. Since updating, my Yahoo Mail account was in a constant state of syncing! It never stopped! Even when I powered off and on, or did a soft reset, it would immediately get stuck in syncing once the phone came back on. I never received any error messages and email would come through and go out, but the sync never stopped running and drained the battery down rapidly. I deleted the account and recreated it. Since then it appears to be functioning properly and the excessive battery drain has stopped....at least for now!