Rooting has nothing to do with battery life. Its just a privilege escalation. Its those apps that are wakelocking in the background that are draining your battery. Just like a laptop if your using up alot of cpu the faster the battery drains. Force stop any apps your not using also resrict background data and auto sync. (Fyi: google playstore will not wok until you enable background data) Get a good anti-virus, permission manager, app for battery stats, and droidwall to blacklist/whitelist apps connecting on wifi or your network.

Ive only had one battery issue and that was my own fault because i wiped my battery data. Got stuck at fully charged was onlg 12% and had to buy a new one.