I have an iPhone 6 (Wi-Fi + LTE), an iPod Touch 5th gen and an iPad Air 2 (Wi-Fi + LTE). My iPhone and iPod batteries average 36+ hours, but my iPad Air 2 can't seem to last a full day despite doing the same amount of work that I usually do on the iPhone 6. Yes, I know the screen is larger, but the battery is also larger so I assumed the battery life would escalate to the same proportions as that of the iPhones. Settings on all of my iOS devices are almost identical, so I don't quite understand what is happening. Can someone help me understand what is going on here?