My battery dies quicker than before, even without using the phone .aslo it shuts down unxpectedly (sometimes shuts down at 30% then i cant restart it until i blog it to the charger) and sometimes jumps from 40% to 20% or from 20% to 3%

Question

hi!
my battery dies quicker than before, even without using the phone
aslo it shuts down unxpectedly (sometimes shuts down at 30% then i cant restart it until i blog it to the charger)
and sometimes jumps from 40% to 20% or from 20% to 3%
i have done many things people recommanded it for me like :
restore : i've done two restores and it gets better for the first 1-2 weeks then it gets worse than before.
also deleted my music list (19gb) in order to make this better (as recommended) but it still the same
my screen brightness is always ALWAYS low , almost the lowest.
i close the apps when i finish using them ALL OF THEM
i dont use the camera and flash , almost rarely. just to save battery.
i dont use the location service always.
i dont charge my phone until it shuts down and i dont unblog it until it reachs 100%
basically i have tried eveything.

Answer 1

Install or Reinstall OS X from Scratch
Be sure you backup your files to an external drive or second internal drive because the following procedure will remove everything from the hard drive.
Boot to the Recovery HD:
Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.
Erase the hard drive:
  1. Select Disk Utility from the main menu and click on the Continue button.
  2. After DU loads select your startup volume (usually Macintosh HD) from the
      left side list. Click on the Erase tab in the DU main window.
  3. Set the format type to Mac OS Extended (Journaled.) Optionally, click on
      the Security button and set the Zero Data option to one-pass. Click on
      the Erase button and wait until the process has completed.
  4. Quit DU and return to the main menu.
Reinstall OS X: Select Reinstall OS X and click on the Install button.
Note: You will need an active Internet connection. I suggest using Ethernet if possible
           because it is three times faster than wireless.