My original 920 and replacement 920 (first one bricked when I reset it while working on the battery drain issue with tech support) both do this occasionally. I don't think it's something simple like "LTE uses more power than 3G" because as this thread says, it drains like crazy and not just faster than usual. I have wondered if it's something to do with low signal or network switching because it seems like a few days it has dropped from 100% off charge to 80% within an hour without any use, then leveled out and been normal once I've left my house (where there's poor AT&T signal--go figure). However, the best fix I've been able to find is the 2 times I haven't been able to get it back to a charger fast enough and it's gone totally dead. After a full charge it always seems to be much better, at least for a few days. Mine hasn't been hot during the crazy discharge times, so I'm wondering whether this is actually an issue with the phone figuring out how much charge is truly left (the estimated time is WAY off compared to my WP7 Samsung Focus) and it helps for it to charge from rock bottom. Still trying to find some pattern, but I don't think it's an app or network speed choice...