So, had my Sensation for a while now and I must say that the phone's battery life varies considerably based on factors over which I seem to have little control. Example: a few days ago, the battery was at 20% after just 6 or so hours! Fully charged. I have deleted many juice-wasting apps so I'm not sure exactly what the problem is. Thanks in advance for your help!
I had really bad battery life, even after I did everything I could to tweak the phone! I replaced the battery and now it's much more energy efficient. If you are certain you have done everything you can as far as tweaking the phone to save power, try replacing the battery.