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.
this graph, we use actual achieved capacity rather than rated capacity.
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.
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?
Excel file can be downloaded by clicking the link below.
Zipped Microsoft Excel file with data and charts for 70 amp
discharge to voltage study.