Or you have a faulty battery or your have some other hardware failure. What you should do is change the battery and see if that helps.
Samsung Galaxy S 4 I9505 | WanamLite v2.6
Samsung Galaxy S II I9100 : AOKP 4.2.1
HTC Touch Pro2 | ROM: Valkyrie 6.5.23115TR2.5
HTC HD2 | DarkStone1337 [FroyoStone Sense - V3.2]
HTC Desire : Oxygen v2.1.3