If you are having issues with your battery life you are not alone
I too was having the same where I had to charge the battery twice.
So I started trying every OS out there for 2 days and they were all crap, which made me think that this is just how the phone is, until someone recommended me to try OS 7.0.0.261, and there was the huge difference!
My phone easily lasts 1-5 to 2 days.
I am on day 2 now and my battery life is still 35% and I am an above average user.
261 has been the best in terms of battery life for me and has 0 errors.
I recommend you try it, and you will definitely thank me for it.
MeterBerry screenshot on day 2:
Download 7.0.0.261
Ensure you have no other OS installed on your PC from the control panel /
Programs & Features
Install the above OS
Then delete the Vendor.xml file
which is usually located in:
C:\Program Files\Common Files\Research In Motion\Apploader
Backup your phone first using the BlackBerry Desktop Manager
Download and install
BBSAK
Run
BBSAK and wipe your device
Now install the new OS using Loader.exe
which is usually located in:
C:\Program Files\Common Files\Research In Motion\Apploader
After the installation is done, restore your backup by launching BlackBerry Desktop Software again
If you have any trouble, contact me and I will be more than happy to help you