Compare the shape of the continuous discharge curves for the A123 and iJoys and another 26650 (any one). You'll see a difference in the shapes of the curves and their voltage levels.
I don't see any difference in shape of discharge curve. All I see, is that A123 LiFePo4 are working in their own voltage diapason and doing it very well.
What the hell is Vappower IRM26650 4200mAh doing in that voltage bracket of 2.26V?
The answer is clear: Straggling to put up with 30A of current. Product of China. These are two identical Vappower IRM26650 4200mAh, were purchased together, on the same time. Granted, they are re-wraps. But seems to me, that there are two completely differed cells, under the skin. Furthermore, Even though, DNA200 had support for LiFePO4 chemistry and could take full advantage of their lower voltage and high current, but there is no DNA200 mod available on 26650 type
batteries. Some DNA75 mods were made for 26650 size cells, but DNA75 does not support LiFePo4
batteries and all their energy, below 2.5 volts is wasted.
P.S. Dear Mooch, I've heard that you are playing with new 20700 and 21700
batteries, how are they? Yes, I spy on you, you are my mentor!