How to use a nokia battery in chinese mp4 handy player ??
 

Got a new idea of extending the playing capability of mpx players..as mobile phone batteries are cheaper and are of comparable sizes..but
i ve some of the questions related to a cell phone battery nokia/samsung..
1. why these batteries have 3 pins ? two are + and - ve but wch one is third one ?
2. If the middle (third ) pin is for charging ... then what is the need of doing this as my sony player have a smaller lithium battery but with only two pins for charging and discharging both ?
3. Can I use this nokia battery for my player ?? If yes then how to do this ? because i ve only two pins available in my player.
My mp4 battery specifications are - >
3.7v lithium. lasts up to 4 hours.
charger is 300mA . Output 5.7v
while my nokia battery is 3.7v too but charger is 800mA.


So people can anyone tell me how to do this ???