If you want to just check the remaining battery percent, just swipe-down from the top of the screen so as to launch quick-settings slider. As you swipe-down, you will be able to see the percentage of battery remaining, in place of the battery icon. It is so cool, isn't it?
If you want to check when application consumed more battery,
Go to Settings> AppManager and choose battery tab. You will now be able to see which application consumed more battery.
TOP Consumers in General:
Screen means --> the battery consumed by Graphics processing unit and the LEDs backlighting, the screen module (array of the LCDs) and the touch unit.
Location is GPS.
System is the basic operating system (blackberry OS 10 or higher).
PIM: Email, BBM, SMS and other built-in messaging systems.