[MetalMan]

The A123s don't even have all that much of a CV phase. If you were to see a charge graph of the cells, you'd see that after about 3.65v the voltage climbs faster and faster.

I've thought about it, and it seems that the higher C Lipo batteries (lower resistance) require less time in the CV phase because of their lower resistance - with a given amp draw, the voltage of the cells increases less than a lower C battery, allowing the battery to take in more energy before hitting the 4.20v mark.