I kinda think that this might belong in the electronics thread, but it is specific to battery technology so I will post it here first.
Here's a charger chip for a single cell lithium ion battery. LM3621. It might prove useful for anyone that wants to mess around with building their own lithium ion power pack.
http://pdf1.alldatasheet.net/datashe...SC/LM3621.html
if you go to bulk battery suppliers, they will sell you multicell charger board that are more practical than designing a charger curcuit from a small chip like this. but for what it's worth, here it is!
regards
Tyler