Hi Denis,dnmun wrote: i think rick has some lifebatts, it would be nice to run them through the CBA too. i was a little concerned earlier about the 11mohm readings of the headway graphs before i saw the 14mohm meausurements of the zeva headway cells, some of the current independent measurements are much higher, but they appear to be well within the lower end of the range of measurements of the other cells, including the Valence and a123 cells.
Great initiative here in comparing all the different cells for internal resistance... BUT make sure you scale the resistance results to each cell's capacity!!! very important here since your conclusion that the headway cells are pretty much as good as the others tested is much scewed because of this. Headway cells are 10Amp-hours each (10 000mAh), and here are the capacities of the much smaller cells tested by zeva (http://zeva.com.au/tech/LiFePO4.php):
PHET PE-1150 - 18650 - 1100mAh [9X]
Huanyu - 18650 - 1000mAh [10X]
Valence - 18650 - 1200mAh [8.3X]
Valence - 26650 - 2400mAh [4.2X]
A123Systems M1 - 26650 - 2300mAh [4.35X]
This means you'll have to scale all your results by these factors in bold for each cell.
Maybe we should have a standard measurement for DC cell resistance? Calculated on a standard 1 Ah base maybe? We have to be comparing apples with apples, so a 10 000mAh headway cell with 15 milli-ohms DC resistance would be 150mohms/Ah, whereas the Huanyu cell results are already in the right scale, so about 70mohms/Ah (twice as good as headway cells). And the A123 cells look like about 7mohms/Ah... 20 times better internal resistance than headway cells for the same capacity!!
Please edit your post with new scaled results so we really can compare cell quality on an even basis.