How do you solve the problem that lithium battery cannot charge after over discharge？

What if the lithium battery fails to charge after excessive discharge? I bought a SONY Ericsson MP3 six months ago, its lithium battery and other uses had always been normal. For my busy work, I left it idle for about a month without turning off the switch. When I used it again to listen to music, it showed that the power was insufficient and then turned off. So i charged it, but after a day it didn't work. The businessman that sold this machine had already changed profession. There’s no guarantee service so I begin to repair by myself.

First turn on the machine and remove the internal battery, test its voltage is normal that the battery is not damaged. Analysis of the reasons may be due to the lithium battery charger has a charging control link, the excessive discharge of lithium battery cannot be charged. Then try the 5 v dc directly to the forced charging on both ends of the lead wire of the battery. The beginning of charging current is very big (more than 400 ma), and then as time goes on current gradually decreases and stabilize. Charging the battery pack after 6 hours back to the original machine wiring, boot play everything is all right. After a few days, when the power is insufficient, the original charger can be used to charge normally again.

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