I have a Samsung Galaxy S II GT-I9105. My problem is battery draining. It works normally after I charge it to full, but as soon as the battery percentage hits 30%, draining accelerates and will go to zero within seconds (literally).
But if I charge it and unplug at 12%, it drains normally again...
What is the problem? Should I buy a new battery?
Update: I have bought a new battery and recalibrated but the same battery draining occurs