I don't know what phone you are using but i've never had great battery life. lol since i got it. Till i got an extended RAVpower batter that doesn't require the custom battery door...but anyways. I have a couple of solutions for you.

NAvigate over to the anthrax kernel forums, join and what not and try their kernel.
IF not Try this kernel by bigwillyg
Wipe dalvik and cache. Then just flash it like a rom and follow the prompts.
https://bitbucket.org/bigwillyg/buttered_toast_shooter/downloads/ButteredToast-RLS14.3.zip

Download an app called kernel tuner from the playstore, go to voltage, take all voltages down by 4-6 steps via the button at the bottom. Also you can chose your governor here or during the kernel flash for whatever balance of battery vs performance you want.

Download an app called battery calibration from the play store, then charge your phone too 100% and calibrate. Let phone run all the way down to 1% then charge back up to 100%

That should do some damage to your problem.

 

Now that you've rooted ur phone u have more control. U decide which apps can run. U can start by identifying those bloatware.

 

stock battery is always bad.

 

If all else fails, you can probably get an ravpower external battery like Jamaal.

 

StevO -I bought the Anker 1900ah and LOVE IT

What I thought was bad Battery life from ROMS was just an old Crappy htc battery....

 

A lot of people are purchasing anker or ravpower probably because of the holidays. Or maybe the sales going on?

 

I can't stand those extended batteries that force you to put on a thicker case back. It totally screws up all case accessories. So, it's very encouraging to hear about the Anker 1900mAh battery. I'll definitely have to try this out. Thanks!

Btw, it looks like RavPower provides one as well that's also 3.7v 1900mAh. I wonder how it compares to Anker.