Taking the information we have already gathered during the baseline battery tests, we can graph the relationship between voltage and SOC under a 70 amp load for some randomly selected batteries.

For this graph, we use actual achieved capacity rather than rated capacity.

Notice that the curve of the graph of cell #74 matches the other 4 cells fairly closely but .02 volts lower. To check this anomaly, we graphed cells #73 and #75. Since their graphs match the other cells, it is unlikely there was a change in test equipment. Cell #74 test temperature and actual capacity is also within the range displayed by the other cells.

Out of curiosity, we add cell #77. This cell was one of the ones that charged in an aberrant fashion. Hitting 4.2 volts after only 50 amp-hrs rather than the 60 amp-hrs that was the norm for 90% of the batteries. #77 and #74 match fairly closely. Why do they both sag more under load than other batteries?

The Excel file can be downloaded by clicking the link below.