Battery life increase on Lumia 1520 after Denim upgrade

It used to get pretty good, maybe 18 hours. Ive never used it light to medium though unless I'm not touching it. Just sitting here on IE listening to bluetooth music has eaten nearly 10% in the last 20 minutes. Ive hard reset it probably 5 times since I've had it, the last was right before the update but even then it wasn't lasting very long. The update didn't help anything though. I may try it again just with hopes it'll fix the Bluetooth from messing up like it has since then. Nothings ever fixed the touch problems either. Its a phone I find tough to love. Its as if this is a beta that I stuck with for another 7 months

I think you have the earlier built of the phone. I had the same issues. Phone heating, bad battery life, and random screen taps. Try to swap it out if possible.
 
It's too late for that now since I've had it over a year. I'm pretty sure that's the problem though, early model.