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BQ27Z561-R2: As the discharge current decreased, the RSOC decreased.

RYOSUKE ARAKI
Prodigy 90 points
Part Number: BQ27Z561-R2
Other Parts Discussed in Thread: GPCCHEM,

Tool/software:

Can someone explain?

RSOC dropped sharply as current draw decreased.

(Top of current graph is cutoff, charging current: over 200mA)

Systems downstream of the gauge switched to power saving mode. (Around line 700 of the log)

If you compare cumulative draw with cumulative charge, you would expect RSOC to be higher.

・Why does this trajectory happen?

・Is there any way to prevent this?

/cfs-file/__key/communityserver-discussions-components-files/196/bq27z561_5F00_202405.log

  • 0
    TI__Mastermind 24741 points

    Hello, 

    Can you also provide me with your gg file? Additionally, have you taken a look at the End of Discharge SOC Jump Elimination document? This document could be helpful here. 

    Regards, 

    Jonny. 

  • 0 in reply to Jonny
    Prodigy 90 points

    Hi Jonny

    I've attached the gg-file.

    This file was read at the start.

    It is not the one obtained when this issue occurred.

    "End of Discharge SOC Jump Elimination" Thank you.

    I've read it. It seems to have a hint, but I'm not sure if it will lead to the answer.

    bq27z561R2_Chem2151.gg.csv

  • 0 in reply to RYOSUKE ARAKI
    TI__Mastermind 24741 points

    Hello, 

    Looking at the gg file you have provided, it looks like you have not completed the learning cycle. This is a possible cause for this behavior. Please refer to the Achieving the Successful Learning Cycle Document for this. Additionally, please ensure that you have received an adequate chemID match (you can use the GPCCHEM tool for this), in order to have a good match you want the DOD % error to be less than 3%. 

    Regards, 

    Jonny. 

  • 0 in reply to Jonny
    Prodigy 90 points

    Hi Jonny

    I thought the learning cycle completed correctly.
    Please let me know what went wrong.

    GPC-REPORT

    Fullscreen 1817.GPC_report.txt Download 
    Chemistry ID selection tool, rev=2.54		
		
Configuration used in present fit:		
ProcessingType = 2		
NumCellSeries = 1		
ElapsedTimeColumn=0		
VoltageColumn = 1		
CurrentColumn = 2		
TemperatureColumn = 3		
		
Best chemical ID : 2151	Best chemical ID max. deviation, % : 1.41	
		
		
		
Summary of all IDs with max. DOD deviation below 3%		
		
Chem ID	max DOD error, %	Max R deviation, ratio
2151	1.41	0.41
2127	1.43	0.59
2135	1.83	0.75
2442	1.93	0.28
242	1.95	0.28
257	1.96	0.46
2795	1.97	0.29
7276	2	0.48
2079	2.02	0.89
217	2.05	0.27
7410	2.27	0.51
5898	2.28	0.31
7498	2.3	0.72
2860	2.34	0.72
5977	2.35	0.48
5917	2.35	0.22
2102	2.41	0.58
2003	2.44	0.6
2082	2.45	0.93
2702	2.45	0.23
2713	2.51	0.2
2552	2.56	0.25
286	2.58	0.3
2833	2.59	0.38
2057	2.63	0.63
5979	2.63	0.47
7553	2.67	0.28
1954	2.7	0.48
2579	2.74	0.38
5975	2.77	0.42
2148	2.79	0.64
1321	2.81	0.77
1991	2.82	0.94
2491	2.84	0.65
2066	2.85	1.14
2877	2.86	0.4
2131	2.88	0.44
7543	2.89	0.2
7059	2.91	0.51
5890	2.93	0.36
1741	2.98	0.42
2863	2.98	0.4
		
Max. deviations for best ID is within recommended range. Chosen best chemical ID is suitable for programming the gauge.		
		
		
Selection of best generic ID for ROM based devices like bq274xx		
		
		
Device / Family #1		
Generic Chem ID	Device/ Voltage/ Chemistry	max DOD error, %
354	bq27411-G1C: 4.35V LiCoO2	14.95
3142	bq27421-G1D: 4.4V LiCoO2	19.1
128	bq27421-G1A: 4.2V LiCoO2	33.3
312	bq27421-G1B: 4.3V LiCoO2	38.11
Best generic ID 354		
Warning: Deviation for best generic ID is above recommended level for this device / family. Consider using another device, flash based gauge or RAM programming of custom ID.		
		
		
Device / Family #2		
Generic Chem ID	Device/ Voltage/ Chemistry	max DOD error, %
354	bq27621:  (ALT_CHEM2) 4.35V LiCoO2	14.95
1210	bq27621:  (ALT_CHEM1) 4.3V LiCoO2	15.18
1202	bq27621: (default) 4.2V LiCoO2	22.19
Best generic ID 354		
Warning: Deviation for best generic ID is above recommended level for this device / family. Consider using another device, flash based gauge or RAM programming of custom ID.		
		
		
Device / Family #3		
Generic Chem ID	Device/ Voltage/ Chemistry	max DOD error, %
3230	bq27426: (default) 4.35V LiCoO2	12.6
3142	bq27426: (ALT-CHEM2) 4.4V LiCoO2	19.1
1202	bq27426: (ALT_CHEM1) 4.2V LiCoO2	22.19
Best generic ID 3230		
Warning: Deviation for best generic ID is above recommended level for this device / family. Consider using another device, flash based gauge or RAM programming of custom ID.

    Log when creating golden image

    ChemID(2151)_make_GI.log

  • 0 in reply to RYOSUKE ARAKI
    TI__Mastermind 24741 points

    Hello, 

    My apologies, it looks like the Qmax and Ra values have been updated successfully, but Impedance Track Gauging is disabled. Please enable Impedance Track Gauging. Additionally, your GPCCHEM report that you received for your cells looks good. 

    Regards, 

    Jonny. 

  • 0 in reply to Jonny
    Prodigy 90 points

    Hi Jonny,

    I saw "SLUA903". Disable the IT gauge by setting the update status to 02.

    That's where I got it wrong.

    Can you tell me what it does when you write the golden image file?

    •  Impedance Track gauging is enabled.

    What else is there?

  • 0 in reply to RYOSUKE ARAKI
    TI__Mastermind 24741 points

    Hello, 

    Please refer to this E2E thread on why you will want Impedance Track to be enabled. 

    Regards, 

    Jonny. 

  • 0 in reply to Jonny
    Prodigy 90 points

    Hi Jonny

    I understand that the impedance track can be enabled.

    However, the impedance track becomes disabled during operation.

    Is this correct?

    In the first place, Do I need to implement a mechanism to enable when disabled?

    Also, from what I read in the E2E thread, "data is not guaranteed when the

    impedance track is disabled." Is there a way to always enable the impedance track?

  • 0 in reply to RYOSUKE ARAKI
    TI__Mastermind 24741 points

    Hello, 

    Please see the following screenshot taken from the bq27z561-R2 TRM. 

    Regards, 

    Jonny.