Is there a DIY on building packs and protection circuits

Is there a DIY on this? I'd like to build a pack that's protected from unprotected Li-Ion cells. Can I use just one PCB to protect all the cells or does each need it's own?

here is another thread about single-cells, nothing really there: http://www.candlepowerforums.com/vb/showthread.php?259246-DIY-18650-protection

here's a link to a vendor for pcb's you can use in packs: http://www.all-battery.com/protectivepcbsforli-ionandli-polymerbatterypacks.aspx

if you buy shink tubing from all-battery, remember their sizes are not diameter, they're flat accross

pads on the board for P (power) are connected to the charging connection, and B (battery) to the battery connections.

i've seen a cheap-o four cell 18650 battery box with some sort of cheap charge balancing built-in for $15 (just thinking built-in BCM'd be nice, but guessing it's configured with 2P 2S) that's built to output 5 volts.