Refining the tester
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Refining the tool
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Worked like hell to get three MIMA systems ready to ship, only to miss the PO by 5 minutes, so I came back home and worked more on the hardware and software for my subpack tester.
I like the overlaid graphs, and the whole event on one log, so one can see the trends and differences between cells during charging and discharging.
I lightened up the load to about 65A instead of the 100, as this subpack was toast when I started with it. The overlaid graphs clearly how the condition of the cells. The white trace is the problem cell 1, and as we view more of these traces, we should be able to run a couple of cycles and simply view the graphs to see what shape the subpack is in, and what cells are having problems.
The charger is one of my big Trojan AGM31 batteries, and I use one of the nichrome resistors to produce a nice comfortable 30A of charge. I will record a charge cycle tomorrow, and hope to install a preamplifier board to bump up the signals levels a bit.
The card only has a 12 bit a/d converter that is looking at +-10V full scale, which yields .0048V per bit. Just barely enough, and this is the major cause of the jitter in the trace. If I amplify the voltage for each cell X4, the traces will be much better to look at,with an effective resolution /bit of .0012.
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