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Ideally, we would be able to discharge each parallel group of the 2S module separately. This would allow us to ‘balance charge’ both cells. This would be fairly complicated and would require more equipment, so we will not pursue this option for now. This does leave the testing open to increase risk of over-voltage and under-voltage, as well as degrading the cells a little more than if properly balancing them.
Since we’re charging at 30A, we will need some decent balancing capability. We will have measurements of the 2 cell voltages from the 2 multimeters. We can burn power from the high cell with a resistor, and control it with a transistor - this technique is called passive balancing and is the simplest way to implement cell balancing. We can control this charge burning mechanism from the A2D 64 channel DAQ module. We would ideally want all of the voltage, current, temperature, and balancing functions to happen from the same python code.
We will charge and discharge each module, assuming that the modules have the same capacity and are at the same voltage.
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