I'm on iOS 8.1.2 and get about 12 hours until dead. Background app refresh, push notifications, Handoff, location services and all those other background processes (except Siri) are disabled. Hopefully a software update results in improvement. My old decrepit iPhone 4 with iOS 7.1.2 could go 48 hours easily. Post your version, settings if relevant, and battery time. Let's create a consolidated results thread for anyone searching on the issue.