BQ40Z60: Help in part selection

I would not use any of the multi-cell Impedance Track gauges in a system side application. They use Qmax and the Ra tables for gauging and it will probably take a few cycles to update these parameters to match your new set of cells. In addition and more critical is that they use capacity based cell balancing, so if Qmax and the Ra table are incorrect, then you run the risk of introducing cell imbalance into the stack. I would use a CEDV gauge such as the bq4050 and a smart charger such as the bq24725A for a gauging, balancing, charger solution. The CEDV gauges use cell voltage based balancing and they should balance your new cells from the start. Of course, FCC will be off and you will have to run at least one full discharge cycle to update it to match your new cells. One caveat on IT is the the bq34z100-G1 has been setup to support system side packs. Qmax and the Ra table can update more quickly and it does not offer cell balancing.