My office is in a 4G extended coverage area (just on the fringe). when I first got my TB, I could literally watch the percentages drop on my battery indicator. 2 hours max and I would be at 20%. I finally realized it was the constant searching for signal and going in and out of 4g, 3g. So I connected to the wifi in the office. Now, after 12 hours I am still above 50%. This is with a few texts, about 15 - 5 minute calls and about 20 minutes surfing the web and checking emails.
I also spent last weekend in an area that has solid 4g coverage and my phone was at 30% after 18 hours. Many texts, a few calls, etc...
Bottom line is that what absolutely kills the TB battery is searching and going in and out of 4g. I suggest connecting to wifi anytime it is available and turning off 4g whenever you are on the fringe of 4g coverage. Believe me you will see a HUGE difference.
BTW - this is not an issue specific to 4g or the TB. a few years ago, I had a moto-Q. I was on a project outside of Philly and that office/area had the same problem, but with 3g...my phone would be constantly searching for 3g would not make it past noon before it was DEAD.