Li-Ion battery packs

[steve6690]

I have been reading on here about the importance of balanced charging for Li-Ion battery packs. For my ongoing dive light project I'd like to use a Li-ion pack which will probably be in a 4s3p configuration. I've seen packs with protection pcb's built in but they don't all appear to have a balancing facility. I'm toying with the idea of building my own pack but I'm unsure of exactly how I'd wire in balancing taps, and what sort of a charger would be needed. Could someone point me in the right direction please or better still, explain it.

this looks good to me : http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=4343

thanks

steve