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Original question:

BQ27421-G1: Initial reading of SoC 3-4% after loading Golden Image and Soft Reset FG but actual SoC should be 20+%

BQ27421-G1: Initial reading of SoC 3-4% after loading Golden Image and Soft Reset FG but actual SoC should be 30+%

Chris Singer
Prodigy 72 points
Part Number: BQ27421-G1

Tool/software:

My previous thread was locked for some reason without allow for any further questions or discussion so I'm forced to write this one.Disappointedhttps://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1519013/bq27421-g1-initial-reading-of-soc-3-4-after-loading-golden-image-and-soft-reset-fg-but-actual-soc-should-be-20)

I am wondering why the fuel gauge cannot established a more accurate reading of the SoC based on the QMax Cell 0 values and R value established during training using the golden image.  The impedance matching algorithm claims to have improved accuracies over voltage correlation as discussed in doc SLUAAR3.pdf but I don't see that here.

My biggest need at this moment is to establish an initial SoC reading even if that reading is 20% inaccurate.

Even a if we used voltage correlation alone I would expect some value to be within 20% of the real SoC so why don't I see that in the fuel gauge?

Could this be a problem of not waiting long enough for the initial SoC to be established? If so can you tell me how long it would take to get a reading and what conditions I can create to hasten that reading?