What's the expected battery life of a Lumia 920?

so I got my new 920 last weekend (running 8.0) and the battery life has been weird. I haven't been using it heavily, just light internet and Messenger, but I get upwards of 30%/h drain. This is with NFC, Bluetooth and the like off. In any case, I've had to invest in a battery bank to last a day of use (and is still not enough). I upgraded to 8.1 on Monday, and the battery life has remained unchanged. Overnight usage when I am asleep tends to be around the 10%/h mark.

My network will gladly replace my handset (warranty not voided by 8.1), but before I consider that, is this a reasonable amount of battery drain? Is there anything more I can do that won't just limit me to calls + SMS?