Battery calibration (and its tools) does nothing to increase battery life. They don't even change your battery counter, as most people would like to believe. Don't trust me? Read up Diane Hackborne's G+ insights on this matter.
The major battery eaters are the display (reduce brightness), Wifi(try using 2G whenever possible) and processor (root/custom ROM your device and underclock it to get significantly better battery life). Oh and most stock manufacturer ROMs have terrible issues with wakelocks and bloatwares causing them. Hence flashing a custom ROM also solves this problem. The DHD has a number of custom ROMs on XDA. I suggest you do some reading on it and that that root or else get an extended battery/portable charger/spare battery as mentioned by the poster above.