Iphone 4 wont charge, computer wont recognize. But he get few procents when he's taked off

I take my Iphone 4 to charge, and i wasnt see it. After bath i saw he dont charge, it less procents then was. In half of hour i saw he got less procent's. I taked unplug and again to charge, taked off phone. Not working. Compiuter wont recognize. He's dead now. But when i take to charge him in pc/wall he's show him's battery and little red. After few min he's took on and have 4% and working, but not charging and not recognize to pc..