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BQ40Z80: When the battery is relaxed for a few hours, the RSOC become 0

Jason Zhao39
Intellectual 360 points
Part Number: BQ40Z80

Charge to 50%, When the battery is relaxed for a few hours, the RSOC become 0. 

How do you configure the RSOC to prevent it from going to 0?  Thanks

  • 0
    TI__Guru 52115 points

    Hi Jason,

    Have you programmed a ChemID into BQ40Z80? Also, have you run the learning cycle? 

    Refer to the app note below.

    http://www.ti.com/lit/an/slua848/slua848.pdf

    Andy

  • 0 in reply to Andy Liu (BMS)
    Intellectual 360 points

    In the absence of learning success, how to configure the SOC to remain unchanged?

    Thanks

  • 0 in reply to Jason Zhao39
    TI__Guru 52115 points

    Hi Jason,

    The learning cycle is critical for the gauge to perform correctly.  Have you been able to run the learning cycle successfully?   

    If not,  let us know what kind of issue you have seen and we will give you some help.

    Andy

  • 0 in reply to Andy Liu (BMS)
    Intellectual 360 points

    In the absence of learning success, SOC changed from 75% to 0% after ten hours.How can the SOC be configured to remain unchanged?

  • 0 in reply to Jason Zhao39
    TI__Guru 52115 points

    Hi Jason,

    As I mentioned before, the learning cycle must be run in order to make sure the gauge device can operate properly. 

    I would suggest you take a look at the app note I provided before and run the learning cycle. 

    If the learning cycle fails, provide your log file and gg file and we will try to help you find out what might be the cause. Thanks.

    Andy

  • 0 in reply to Andy Liu (BMS)
    Intellectual 360 points

    Hi，Andy

    The battery I'm using doesn't have a matching chemical ID, so it won't work.

    We just want to use the coulometer part of the chip right now.

    Thanks.

  • 0 in reply to Jason Zhao39
    TI__Guru 52115 points

    Hi Jason,

    I suggest you use the GPCCEHM online tool to get a matching chemistry ID for your battery.

    http://www.ti.com/tool/GPCCHEM

    Andy

  • 0 in reply to Andy Liu (BMS)
    Intellectual 360 points

    Hi，Andy

    Already used, no matching chemical ID

    We just want to use the coulometer part of the chip right now.

    Thanks.

  • 0 in reply to Jason Zhao39
    TI__Guru 52115 points

    Hi Jason,

    Can you share with us the file you submitted for matching chemistry ID and also the report you received? Thanks.

    Andy

  • 0 in reply to Andy Liu (BMS)
    Intellectual 360 points

    It's report.

    Fullscreen 2313.GPC_report.txt Download 
    Chemistry ID selection tool, rev=2.48		
		
Configuration used in present fit:		
ProcessingType=2		
NumCellSeries=1		
ElapsedTimeColumn=0		
VoltageColumn=1		
CurrentColumn=2		
TemperatureColumn=3		
		
Best chemical ID : 705	Best chemical ID max. deviation, % : 37.26	
		
		
		
Summary of all IDs with max. DOD deviation below 3%		
		
Chem ID	max DOD error, %	Max R deviation, ratio
0	0	0
		
Accuracy Error: Deviation is so high that it is most likely due to anomaly in the data. Please check that data files have recomended format, units and test schedule * Warning: First OCVpoint has non-zero current I=  -0.15 Please make sure you have a 2 hr relaxation period before the beginning of discharge. * Warning: Last OCVpoint has non-zero current I=  -0.15 Please make sure you have a 5 hr relaxation period after the end of discharge.		
		
		
Selection of best generic ID for ROM based devices like bq274xx		
		
		
Device / Family #1		
Generic Chem ID	Device/ Voltage/ Chemistry	max DOD error, %
312	bq27421-G1B: 4.3V LiCoO2	100
354	bq27411-G1C: 4.35V LiCoO2	200
3142	bq27421-G1D: 4.4V LiCoO2	200
128	bq27421-G1A: 4.2V LiCoO2	200
Best generic ID 312		
Warning: Generic ID Deviation is so high that it is most likely due to anomaly in the data. Please check that data files have recomended format, units and test schedule		
		
		
Device / Family #2		
Generic Chem ID	Device/ Voltage/ Chemistry	max DOD error, %
1210	bq27621:  (ALT_CHEM1) 4.3V LiCoO2	100
354	bq27621:  (ALT_CHEM2) 4.35V LiCoO2	200
1202	bq27621: (default) 4.2V LiCoO2	200
Best generic ID 1210		
Warning: Generic ID Deviation is so high that it is most likely due to anomaly in the data. Please check that data files have recomended format, units and test schedule		
		
		
Device / Family #3		
Generic Chem ID	Device/ Voltage/ Chemistry	max DOD error, %
3230	bq27426: (default) 4.35V LiCoO2	100
3142	bq27426: (ALT-CHEM2) 4.4V LiCoO2	200
1202	bq27426: (ALT_CHEM1) 4.2V LiCoO2	200
Best generic ID 3230		
Warning: Generic ID Deviation is so high that it is most likely due to anomaly in the data. Please check that data files have recomended format, units and test schedule		
		
		
Warning: First OCVpoint has non-zero current I=  -0.15 Please make sure you have a 2 hr relaxation period before the beginning of discharge.		
Warning: Last OCVpoint has non-zero current I=  -0.15 Please make sure you have a 5 hr relaxation period after the end of discharge.

  • 0 in reply to Jason Zhao39
    TI__Guru 52115 points

    I think there should be something wrong with your IVT file you submitted. 

    Check the following app note.

    http://www.ti.com/lit/an/slva725a/slva725a.pdf

  • 0 in reply to Jason Zhao39
    Intellectual 360 points

    Hi Andy

         Do you have any good Suggestions.

        We just want to use the coulometer part of the chip right now.

        How do you configure the RSOC to prevent it from going to 0?  Thanks

  • 0 in reply to Jason Zhao39
    TI__Guru 52115 points

    Hi Jason,

    An accurate state of charge prediction depends on a proper chem id.  Without the correct chem id, the RSOC reading the gauge reports will NOT be correct.

    Andy