• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 63 subscribers
  • Views 1446 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ34Z100-G1: BQ34z100-g1. True RC and true FCC

Gorka Lorea
Expert 1620 points
Part Number: BQ34Z100-G1

Hi,

I am using the BQ34z100-g1 to estimate SoC of an 8s2p LiFePO4. 

The first time I connect the BQ 34z100 to the battery (after having loaded in it the correct chemID, calibrated the device and loaded the golden image) it always estimates the SoC a bit high so it brings me a problem. I do not know if this error is because the flat voltage curve of LiFePO4 or because I have not chose the correct chemID. The error can be around 10%. 

When I start charging the battery and SoC goes to 100% the battery is not full so charge continues and TrueRC becomes bigger than True FCC (for example True RC = 7000mAh and true FCC = 6700mAh). 

When I start the discharge the SoC remains at 100% until True RC goes under True FCC and this is not correct. I am absolutely sure that my battery will never goes higher than 6700mAh so:

1. Is there any way of limiting the True RC and True FCC parameters to a defined value?

Thank you very much in advance, 

  • 0
    TI__Guru* 76230 points
    Hi Gorka
    The initial SOC error is due to the flatness of LFP cells.

    For your second issue, what do you have your taper current set to in data flash of the gauge and what current do you have your charger tapering at?

    This determines when the FC flag gets set. Yo need to review your primary charge termination conditions and set your taper current appropriately.
    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Expert 1620 points

    Hi Onyx,

    Thanks for your time, I really appreciate it. 

    I have logged this issue because it makes no sense for me. Here is the log. WrongFCset171010.log

    I have the next values (you can see it in the .gg file

    Fullscreen bq34z100_Cegasa.gg.txt Download 
    * Texas Instruments Data Flash File
* File created Tue Oct 10 07:53:04 2017
*
* Device Number 100
* Firmware Version 0.16
* Build Number not available
* Order Number not available
*
* bqz Device Number 100
* bqz Firmware Version 0.16
* bqz Build Number 17
*
* Field Order: Class name, Subclass name, Parameter name, Parameter Value, Display Units
"Configuration","Safety","OT Chg","55.0","1degC"
"Configuration","Safety","OT Chg Time","2","Seconds"
"Configuration","Safety","OT Chg Recovery","50.0","1degC"
"Configuration","Safety","OT Dsg","60.0","1degC"
"Configuration","Safety","OT Dsg Time","2","Seconds"
"Configuration","Safety","OT Dsg Recovery","55.0","1degC"
"Configuration","Charge Inhibit Cfg","Chg Inhibit Temp Low","0","1degC"
"Configuration","Charge Inhibit Cfg","Chg Inhibit Temp High","45.0","1degC"
"Configuration","Charge Inhibit Cfg","Temp Hys","5.0","1degC"
"Configuration","Charge","Suspend Low Temp","-5.0","1degC"
"Configuration","Charge","Suspend High Temp","55.0","1degC"
"Configuration","Charge","Pb EFF Efficiency","100","%"
"Configuration","Charge","Pb Temp Comp","24.960","%"
"Configuration","Charge","Pb Drop Off Percent","96","%"
"Configuration","Charge","Pb Reduction Rate","10.000","%"
"Configuration","Charge Termination","Taper Current","100","mAmp"
"Configuration","Charge Termination","Min Taper Capacity","25","mAmpHr"
"Configuration","Charge Termination","Cell Taper Voltage","25","mVolt"
"Configuration","Charge Termination","Current Taper Window","40","Seconds"
"Configuration","Charge Termination","TCA Set %","99","Percent"
"Configuration","Charge Termination","TCA Clear %","95","Percent"
"Configuration","Charge Termination","FC Set %","100","Percent"
"Configuration","Charge Termination","FC Clear %","98","Percent"
"Configuration","Charge Termination","DODatEOC Delta T","10.0","1degC"
"Configuration","Charge Termination","NiMH Delta Temp","3.0","1degC"
"Configuration","Charge Termination","NiMH Delta Temp Time","180","Seconds"
"Configuration","Charge Termination","NiMH Hold Off  Time","100","Seconds"
"Configuration","Charge Termination","NiMH Hold Off Current","240","mAmp"
"Configuration","Charge Termination","NiMH Hold Off  Temp","25.0","1degC"
"Configuration","Charge Termination","NiMH Cell Negative Delta Volt","17","mVolt"
"Configuration","Charge Termination","NiMH Cell Negative Delta Time","16","Seconds"
"Configuration","Charge Termination","NiMH Cell Neg Delta Qual Volt","4200","mVolt"
"Configuration","Data","Manufacture Date","1980-1-1","Day + Mo*32 + (Yr -1980)*256"
"Configuration","Data","Serial Number","0001","hex"
"Configuration","Data","Cycle Count","8","Count"
"Configuration","Data","CC Threshold","5800","mAmpHr"
"Configuration","Data","Max Error Limit","100","%"
"Configuration","Data","Design Capacity","6400","MilliAmpHour"
"Configuration","Data","Design Energy","16640","MilliWattHour"
"Configuration","Data","SOH Load I","-400","MilliAmp"
"Configuration","Data","Cell Charge Voltage T1-T2","3600","mV"
"Configuration","Data","Cell Charge Voltage T2-T3","3600","mV"
"Configuration","Data","Cell Charge Voltage T3-T4","3600","mV"
"Configuration","Data","Charge Current T1-T2","10","Percent"
"Configuration","Data","Charge Current  T2-T3","50","Percent"
"Configuration","Data","Charge Current  T3-T4","30","Percent"
"Configuration","Data","JEITA T1","0","degC"
"Configuration","Data","JEITA T2","10","degC"
"Configuration","Data","JEITA T3","45","degC"
"Configuration","Data","JEITA T4","55","degC"
"Configuration","Data","Design Energy Scale","10","Number"
"Configuration","Data","Device Name","bq34z100-G1","-"
"Configuration","Data","Manufacturer Name","Texas Inst.","-"
"Configuration","Data","Device Chemistry","LION","-"
"Configuration","Discharge","SOC1 Set Threshold","150","mAh"
"Configuration","Discharge","SOC1 Clear Threshold","175","mAh"
"Configuration","Discharge","SOCF Set Threshold","75","mAh"
"Configuration","Discharge","SOCF Clear Threshold","100","mAh"
"Configuration","Discharge","Cell BL Set Volt Threshold","2800","mVolt"
"Configuration","Discharge","Cell BL Set Volt Time","2","Seconds"
"Configuration","Discharge","Cell BL Clear Volt Threshold","2900","mVolt"
"Configuration","Discharge","Cell BH Set Volt Threshold","4300","mVolt"
"Configuration","Discharge","Cell BH Volt Time","2","Seconds"
"Configuration","Discharge","Cell BH  Clear Volt Threshold","4200","mVolt"
"Configuration","Discharge","Cycle Delta","0.05","%"
"Configuration","Manufacturer Data","Pack Lot Code","0000","hex"
"Configuration","Manufacturer Data","PCB Lot Code","0000","hex"
"Configuration","Manufacturer Data","Firmware Version","0000","hex"
"Configuration","Manufacturer Data","Hardware Revision","0000","hex"
"Configuration","Manufacturer Data","Cell Revision","0000","hex"
"Configuration","Manufacturer Data","DF Config Version","0000","hex"
"Configuration","Lifetime Data","Lifetime Max Temp","30.0","1degC"
"Configuration","Lifetime Data","Lifetime Min Temp","-40.9","1degC"
"Configuration","Lifetime Data","Lifetime Max Chg Current","3661","mAmp"
"Configuration","Lifetime Data","Lifetime Max Dsg Current","-15150","mA"
"Configuration","Lifetime Data","Lifetime Max Pack Voltage","1495","20mV"
"Configuration","Lifetime Data","Lifetime Min Pack Voltage","0","20mV"
"Configuration","Lifetime Temp Samples","LT Flash Cnt","78","Count"
"Configuration","Registers","Pack Configuration","28a1","flags"
"Configuration","Registers","Pack Configuration B","a6","flags"
"Configuration","Registers","Pack Configuration C","27","flags"
"Configuration","Registers","LED_Comm Configuration","00","flags"
"Configuration","Registers","Alert Configuration","0000","flags"
"Configuration","Registers","Number of series cell","8","num"
"Configuration","Lifetime Resolution","LT Temp Res","1.0","1degC"
"Configuration","Lifetime Resolution","LT Cur Res","100","mA"
"Configuration","Lifetime Resolution","LT V Res","1","20mV"
"Configuration","Lifetime Resolution","LT Update Time","60","Seconds"
"Configuration","LED Display","LED Hold Time","4","Num"
"Configuration","Power","Flash Update OK Cell Volt","2500","mVolt"
"Configuration","Power","Sleep Current","10","mAmp"
"Configuration","Power","FS Wait","0","Seconds"
"System Data","Manufacturer Info","Block A 0","00","hex"
"System Data","Manufacturer Info","Block A 1","00","hex"
"System Data","Manufacturer Info","Block A 2","00","hex"
"System Data","Manufacturer Info","Block A 3","00","hex"
"System Data","Manufacturer Info","Block A 4","00","hex"
"System Data","Manufacturer Info","Block A 5","00","hex"
"System Data","Manufacturer Info","Block A 6","00","hex"
"System Data","Manufacturer Info","Block A 7","00","hex"
"System Data","Manufacturer Info","Block A 8","00","hex"
"System Data","Manufacturer Info","Block A 9","00","hex"
"System Data","Manufacturer Info","Block A 10","00","hex"
"System Data","Manufacturer Info","Block A 11","00","hex"
"System Data","Manufacturer Info","Block A 12","00","hex"
"System Data","Manufacturer Info","Block A 13","00","hex"
"System Data","Manufacturer Info","Block A 14","00","hex"
"System Data","Manufacturer Info","Block A 15","00","hex"
"System Data","Manufacturer Info","Block A 16","00","hex"
"System Data","Manufacturer Info","Block A 17","00","hex"
"System Data","Manufacturer Info","Block A 18","00","hex"
"System Data","Manufacturer Info","Block A 19","00","hex"
"System Data","Manufacturer Info","Block A 20","00","hex"
"System Data","Manufacturer Info","Block A 21","00","hex"
"System Data","Manufacturer Info","Block A 22","00","hex"
"System Data","Manufacturer Info","Block A 23","00","hex"
"System Data","Manufacturer Info","Block A 24","00","hex"
"System Data","Manufacturer Info","Block A 25","00","hex"
"System Data","Manufacturer Info","Block A 26","00","hex"
"System Data","Manufacturer Info","Block A 27","00","hex"
"System Data","Manufacturer Info","Block A 28","00","hex"
"System Data","Manufacturer Info","Block A 29","00","hex"
"System Data","Manufacturer Info","Block A 30","00","hex"
"System Data","Manufacturer Info","Block A 31","00","hex"
"Gas Gauging","IT Cfg","Load Select","1","Number"
"Gas Gauging","IT Cfg","Load Mode","0","Number"
"Gas Gauging","IT Cfg","Res Current","10","mAmp"
"Gas Gauging","IT Cfg","Max Res Factor","50","num"
"Gas Gauging","IT Cfg","Min Res Factor","1","num"
"Gas Gauging","IT Cfg","Ra Filter","500","num"
"Gas Gauging","IT Cfg","Min PassedChg NiMH-LA 1st Qmax","50","%"
"Gas Gauging","IT Cfg","Maximum Qmax Change","100","%"
"Gas Gauging","IT Cfg","Cell Terminate Voltage","2500","mVolt"
"Gas Gauging","IT Cfg","Cell Term V Delta","200","mVolt"
"Gas Gauging","IT Cfg","ResRelax Time","500","Seconds"
"Gas Gauging","IT Cfg","User Rate-mA","0","MilliAmp"
"Gas Gauging","IT Cfg","User Rate-Pwr","0","mW/cW"
"Gas Gauging","IT Cfg","Reserve Cap-mAh","0","MilliAmpHour"
"Gas Gauging","IT Cfg","Reserve Energy","0","mWh/cWh"
"Gas Gauging","IT Cfg","Max Scale Back Grid","4","num"
"Gas Gauging","IT Cfg","Cell Min DeltaV","0","mVolt"
"Gas Gauging","IT Cfg","Ra Max Delta","15","%"
"Gas Gauging","IT Cfg","Design Resistance","54","mOhms"
"Gas Gauging","IT Cfg","Reference Grid","4","-"
"Gas Gauging","IT Cfg","Qmax Max Delta %","10","mAmpHour"
"Gas Gauging","IT Cfg","Max Res Scale","32000","Num"
"Gas Gauging","IT Cfg","Min Res Scale","1","Num"
"Gas Gauging","IT Cfg","Fast Scale Start SOC","10","%"
"Gas Gauging","IT Cfg","Charge Hys V Shift","40","mVolt"
"Gas Gauging","IT Cfg","Smooth Relax Time","1000","s"
"Gas Gauging","Current Thresholds","Dsg Current Threshold","60","mAmp"
"Gas Gauging","Current Thresholds","Chg Current Threshold","75","mAmp"
"Gas Gauging","Current Thresholds","Quit Current","40","mAmp"
"Gas Gauging","Current Thresholds","Dsg Relax Time","60","Seconds"
"Gas Gauging","Current Thresholds","Chg Relax Time","60","Seconds"
"Gas Gauging","Current Thresholds","Cell Max IR Correct","400","mV"
"Gas Gauging","State","Qmax Cell 0","7194","mAmpHr"
"Gas Gauging","State","Cycle Count","5","num"
"Gas Gauging","State","Update Status","06","num"
"Gas Gauging","State","Cell V at Chg Term","3607","mVolt"
"Gas Gauging","State","Avg I Last Run","-2073","mAmp"
"Gas Gauging","State","Avg P Last Run","-654","MilliWattHour"
"Gas Gauging","State","Cell Delta Voltage","302","mVolt"
"Gas Gauging","State","T Rise","20","Num"
"Gas Gauging","State","T Time Constant","1000","Num"
"Ra Tables","Ra0 Table","Ra Flag","0000","Hex"
"Ra Tables","Ra0 Table","Ra 0","60","Num"
"Ra Tables","Ra0 Table","Ra 1","56","Num"
"Ra Tables","Ra0 Table","Ra 2","52","Num"
"Ra Tables","Ra0 Table","Ra 3","52","Num"
"Ra Tables","Ra0 Table","Ra 4","45","Num"
"Ra Tables","Ra0 Table","Ra 5","48","Num"
"Ra Tables","Ra0 Table","Ra 6","53","Num"
"Ra Tables","Ra0 Table","Ra 7","50","Num"
"Ra Tables","Ra0 Table","Ra 8","52","Num"
"Ra Tables","Ra0 Table","Ra 9","52","Num"
"Ra Tables","Ra0 Table","Ra 10","54","Num"
"Ra Tables","Ra0 Table","Ra 11","54","Num"
"Ra Tables","Ra0 Table","Ra 12","81","Num"
"Ra Tables","Ra0 Table","Ra 13","184","Num"
"Ra Tables","Ra0 Table","Ra 14","426","Num"
"Ra Tables","Ra0x Table","Ra Flag","0055","Hex"
"Ra Tables","Ra0x Table","Ra 0","60","Num"
"Ra Tables","Ra0x Table","Ra 1","56","Num"
"Ra Tables","Ra0x Table","Ra 2","52","Num"
"Ra Tables","Ra0x Table","Ra 3","52","Num"
"Ra Tables","Ra0x Table","Ra 4","45","Num"
"Ra Tables","Ra0x Table","Ra 5","48","Num"
"Ra Tables","Ra0x Table","Ra 6","53","Num"
"Ra Tables","Ra0x Table","Ra 7","50","Num"
"Ra Tables","Ra0x Table","Ra 8","60","Num"
"Ra Tables","Ra0x Table","Ra 9","60","Num"
"Ra Tables","Ra0x Table","Ra 10","62","Num"
"Ra Tables","Ra0x Table","Ra 11","62","Num"
"Ra Tables","Ra0x Table","Ra 12","93","Num"
"Ra Tables","Ra0x Table","Ra 13","212","Num"
"Ra Tables","Ra0x Table","Ra 14","492","Num"
"Calibration","Data","CC Gain","10.343","mohm"
"Calibration","Data","CC Delta","10.322","mohm"
"Calibration","Data","CC Offset","-1553","num"
"Calibration","Data","Board Offset","0","num"
"Calibration","Data","Int Temp Offset","0","degC"
"Calibration","Data","Ext Temp Offset","-1.8","degC"
"Calibration","Data","Voltage Divider","37500","mVolt"
"Calibration","Current","Deadband","5","mAmp"
"Security","Codes","Sealed to Unsealed","36720414","hex"
"Security","Codes","Unsealed to Full","ffffffff","hex"
"Security","Codes","Authen Key3","01234567","hex"
"Security","Codes","Authen Key2","89abcdef","hex"
"Security","Codes","Authen Key1","fedcba98","hex"
"Security","Codes","Authen Key0","76543210","hex"
    )

    Charging voltage = 28800mV

    Taper current = 100mAh

    Min Taper Capacity = 25mAh

    Cell Tapper Window = 40s

    You can see how, as soon as the SoC goes to 100% the FC flag is set (although primary charge termination conditions has not been met; battery voltage is at 28.336 (< 28.800 - 8x25mV) and current is 2496mA > tapper current).

    After that true RC continues increasing its value above the true FCC (True FCC = 6773mAh and true RC raise to 7371mAh)

    When the charger stops the charge and the application starts to discharge the battery the remaining capacity remains at the same value as FCC (= 6773mAh) until True RC goes under true FCC value. Thats are almost 600mAh in which SoC remains at 100% and this is not correct.

    1. Why FC flag is set although primary charge termination conditions have not been met?

    2. How can I solve this problem?

    3. Every time I restart the gauge I have the same problem because of an overstimate of the SoC. 

    Thak you very much in advance, 

  • 0 in reply to Gorka Lorea
    Expert 1620 points
    Hi again Onyx,
    I think I have discovered what my problem was. I did not let the charger to do a charge termination so True RC never drops to true FCC.
    I have done now a charge termination (80seconds with current below 100mAh) and I have seen that True RC drops to True FCC.
    Thank you very much,
  • 0 in reply to Gorka Lorea
    TI__Guru* 76230 points
    Hi Gorka
    I looked at your gg file, You need to set FC set to -1 for the gauge to set the FC flag based on primary charge termination.
    To prevent the gauge from getting to 100% to early, reduce Ra0 in both resitance tables by half. Say to something like 30. If the current is still too large when 100% is reached, reduce it even further to about 15. That should be the minimum you reduce it to. If further adjustment is needed reduce Ra1 by half to 27. Let me know how this works out for you

    thanks
    Onyx