Hi,
We are testing out the Cell Balancing feature and have seen that the higher voltage cell is discharging correctly, the data is shown below. This is performed with batteries that match the ChemID: 2123. A valid learning cycle has already been loaded to the FG. I’ve attached the golden file we are using.
We are seeing 2 issues:
- The higher cell does not stop when the voltage matches the lower cell, it continues, and when it approaches 15-20mV difference, it switches over and starts to balance the other cell. This seems to continue indefinitely. Why would the cells not stop when they are within ~0mV nominally? Is there a specific register setting that needs to be set to define a stopping voltage difference threshold?
- Balancing of the batteries implies that the higher cell is being discharged and therefore losing capacity. However, the battery percentage capacity was read back and it was still reporting 100% (even though as can be seen in the graphs, the batteries had been discharged for ~15hrs at ~15mA, therefore losing ~225mAh from our 3500mAh battery, i.e. ~6.4%. Our expectation is that the FG will track the capacity difference being incurred by the internal cell balancing FETs since the sense resistor won’t see any current flowing across it. We would also expect that the algorithm would take into account the voltage levels to determine the capacity level and not just the coulomb counter. This is a concern to us since we would rely on the Min RSOC for Balancing register (0x4714), and if the cells continue to balance but a decrease in SOC doesn’t occur, then the balancing will never hit that limit and the batteries will fully discharge. Is there a setting issue?
/cfs-file/__key/communityserver-discussions-components-files/196/SL_5F00_GoldenFile.txt
