Other Parts Discussed in Thread: BQSTUDIO
We are using the bq40z50-R1 in a 4S2P battery pack. When bqStudio is scanning the registers (for example, every 15 seconds) with no load current and no charge current on the pack, we observe that the four cell current parameters (Cell 1 Current, Cell 2 Current, Cell 3 Current, and Cell 4 Current) are often non-zero in about one-third of the scans. For example, we might see:
Cell 1 Current = -10 mA
Cell 2 Current = -39 mA
Cell 3 Current = -26 mA
Cell 4 Current = -94 mA
The current "speedometer" in the Dashboard indicates about -6 mA when this occurs. Then all the readings return to 0 mA for the next 2 or 3 scans.
Why are the indicated currents non-zero when there is no current flowing into or out of the battery pack? Is this having an effect on the calculation of Remaining State of Charge and/or remaining capacity?
Our current sensing resistor is a very low value: three 1 milliohm resistors in parallel. However, we perform current calibration in production and get accurate current readings during actual charge and discharge.
