• State
  • Locked Locked
  • Replies 13 replies
  • Subscribers 63 subscribers
  • Views 394 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.

Original question:

BQ76940: VCT not triggering

BQ78350-R1A: VCT not triggering

Noel Binny Abraham
Intellectual 535 points
Part Number: BQ78350-R1A
Other Parts Discussed in Thread: BQSTUDIO, BQ78350, BQ40Z80

Tool/software:

Hi Team,

We were testing the BMS for a 13S configuration and have observed that the VCT is not being hit eventhough all the conditions are being satisfied.
I have the log files and .gg files for this ready with me and attaching them below. Do go through it and let me know if im doing something wrong.

There's one more problem that we've faced during testing. We removed the temp sensors while charging was active, the guage read -52 deg.C, UTC bit was set to high as shown on BQSTUDIO, and all the conditions for fet turn-off was achieved under UTC, but the charging never got suspended. The SU bit was also toggled to high, but no change was observed with the CHG and DSG bits. Charging continued and this is not what we were expecting. 

VCT Log file:
RT501_003_chg test 3 continued 2.log


.gg file:
13S_V1_3.gg.csv

Best Regards,
Noel Binny Abraham

  • 0
    TI__Guru 61456 points

    Please make sure that you pass at least 0.25mAh for each 40s window after the current drops below taper current. Otherwise VCT won't trigger.

    The gauge will turn off the charge pump for the charge FET if SafetyStatus[UTC] = 1 (note that SafetyAlert is not enough). OperationStatus[XCHG] will turn 0 (green) and this indicates that the gauge turned off the charge FET charge pump. Note that this is open loop so the gauge relies on the FET to turn off completely. If that's not the case, then charging will continue.

  • 0 in reply to Dominik Hartl11
    Intellectual 535 points

    Hi Dominik,

    We beleive that the 0.25mAh accumulation criterion is being satisfied along with all the other requirements. Can there be any other issue that might be stopping the VCT from triggering?

    As observed, the SafetyStatus[UTC] is being set to 1 right after the SafetyAlert is set to 1. This should turn off the CHG FET's right? According to the definition for the "Trip" condition?

    These are the snapshots before and after UTC is set.

    Charge test before UTC: 


    Charge test after UTC: 

    As you can see here, the SU bit is also being set but FETs are not turning off (XCHG is not being set too). What might be the problem here?

    Dominik Hartl11 said:
    Note that this is open loop so the gauge relies on the FET to turn off completely. If that's not the case, then charging will continue.



    Is the driver not being able to turn off the FET? Or is it something else? Im not able to understand what and where to troubleshoot, do help me out.

    Thanks and Regards,
    Noel Binny Abraham

  • 0 in reply to Noel Binny Abraham
    TI__Guru 61456 points

    A protection event (flag) in SafetyStatus will cause a FET action (if enabled).

    Your screenshots don't show OperationStatus A with the XCHG and XDSG bits. Are you sure that one or both are off?

    >Is the driver not being able to turn off the FET? 

    If you are in doubt, check the voltage on the FET gate with a volt meter. This should tell you if the gauge controls the FET correctly. If the FET still conducts even though the voltage on the gate is within the "off" specification from the bq78350 datasheet then the problem is with the FET.

  • 0 in reply to Dominik Hartl11
    Intellectual 535 points
    Dominik Hartl11 said:
    Your screenshots don't show OperationStatus A with the XCHG and XDSG bits. Are you sure that one or both are off?

    Yes they are off (Green State)

    Dominik Hartl11 said:
    >Is the driver not being able to turn off the FET? 

    In an event where there is a COV, CUV or OCD/SCD, the Fets are being turned off. The CHG and DSG bits are being toggled accordingly as seen on the BQstudio app in case of  COV, CUV or OCD/SCD.

    Dominik Hartl11 said:
    If you are in doubt, check the voltage on the FET gate with a volt meter. This should tell you if the gauge controls the FET correctly. If the FET still conducts even though the voltage on the gate is within the "off" specification from the bq78350 datasheet then the problem is with the FET.

    Did check this. The fet driver still supplies a 10V to the gate-source even when a UTC/UTD condition is met. The CHG and DSG pins of the IC also gives a 10V output in this case, so i do not think that there is a problem with the fets.

    Any other places to look for an error in the whole system?


    Also, we still cannot figure out why the VCT is not being triggered. :( 
    Here is the data for end of charge cycle for your reference:
    5430.log

    Fullscreen 2.log Download 
    Thu Jan 09 17:52:30 IST 2025

Device Version Info = 1e9b_3_00
BQZ Device Name = bq78350R3
BQZ Firmware Version = V3_00_BLD31

Design Capacity = 6300
Design Voltage = 3700
Specification Info = 0x1031
Manufacturer Date = 2024-11-7
Serial Number = 0x0002
Manufacturer Name = Revogreen Tech
Device Name = RT501
Device Chemistry = LION

Sample,DateTime,ElapsedTime,ManufAccess,RemCapAlarm,RemTimeAlarm,BattMode,@Rate(@),@TimeFull,@TimeEmpty,@RateOK,Temperature,Voltage,Current,AvgCurr,MaxErr,RSOC,ASOC,RemCap,FullChgCap,RunTimeEmty,RunTimeEmty,AvgTimeFull,ChgCurr,ChgVolt,BattStat,CycleCnt,PendingEdv,SoH,OpStatA,OpStatB,TempRange,ChgStat,GaugeStat,MfgStat,SafetyAlertAB,SafetyStatAB,SafetyAlertCD,SafetyStatCD,PFAlertAB,PFStatAB,PFStatAB,CellVolt1,CellVolt2,CellVolt3,CellVolt4,CellVolt5,CellVolt6,CellVolt7,CellVolt8,CellVolt9,CellVolt10,CellVolt11,CellVolt12,CellVolt13,CellVolt14,CellVolt15,ExtAvgCellVolt,TS1 Temp,TS2 Temp,TS3 Temp,CellTemp,FetTemp,GaugeInternalTemp,LogRowTime(ms),LogStatus
1,2025-01-09 17:52:34,4.017,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54581,15,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4203,4201,4202,4201,4207,4200,4201,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.3,999,SUCCESS
2,2025-01-09 17:52:38,8.020,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54586,14,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4203,4202,4202,4201,4207,4200,4201,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.3,961,SUCCESS
3,2025-01-09 17:52:42,12.031,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54580,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4200,4201,4200,4203,4203,4203,4201,4201,4204,4200,4198,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.4,1002,SUCCESS
4,2025-01-09 17:52:46,16.042,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54583,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4200,4201,4200,4203,4206,4202,4201,4201,4204,4200,4198,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.3,957,SUCCESS
5,2025-01-09 17:52:50,20.045,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54584,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4198,4201,4202,4200,4203,4206,4202,4201,4201,4204,4200,4198,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.4,953,SUCCESS
6,2025-01-09 17:52:54,24.046,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54585,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4198,4200,4202,4200,4203,4206,4202,4201,4201,4204,4200,4198,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.4,951,SUCCESS
7,2025-01-09 17:52:58,28.047,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54589,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4209,4201,4203,4201,4207,4200,4201,4199,4169,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.5,951,SUCCESS
8,2025-01-09 17:53:02,32.061,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54589,17,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4210,4200,4203,4201,4207,4199,4200,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.5,984,SUCCESS
9,2025-01-09 17:53:06,36.074,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54587,17,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4210,4200,4203,4200,4207,4200,4201,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.4,938,SUCCESS
10,2025-01-09 17:53:10,40.081,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54589,17,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4210,4200,4203,4200,4207,4200,4201,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.5,980,SUCCESS
11,2025-01-09 17:53:14,44.089,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54588,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4207,4200,4203,4201,4207,4200,4201,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.5,941,SUCCESS
12,2025-01-09 17:53:18,48.103,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54582,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4204,4201,4203,4201,4207,4200,4200,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.4,960,SUCCESS
13,2025-01-09 17:53:22,52.108,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54583,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4203,4200,4203,4201,4207,4200,4201,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.5,953,SUCCESS
14,2025-01-09 17:53:26,56.118,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54585,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4203,4200,4203,4201,4207,4200,4201,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.5,941,SUCCESS
15,2025-01-09 17:53:30,60.127,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54590,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4209,4200,4203,4201,4207,4200,4201,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.6,980,SUCCESS
16,2025-01-09 17:53:34,64.141,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54589,15,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4210,4200,4203,4200,4207,4200,4200,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.5,934,SUCCESS
17,2025-01-09 17:53:38,68.151,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54581,14,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4200,4201,4200,4203,4206,4202,4201,4201,4200,4200,4198,4169,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.6,942,SUCCESS
18,2025-01-09 17:53:42,72.154,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54580,17,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4198,4200,4202,4200,4203,4206,4202,4201,4201,4199,4200,4198,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.6,936,SUCCESS
19,2025-01-09 17:53:46,76.161,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54579,15,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4198,4200,4202,4200,4203,4206,4202,4201,4201,4199,4200,4198,4169,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.6,977,SUCCESS
20,2025-01-09 17:53:50,80.163,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54579,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4200,4202,4200,4203,4206,4202,4201,4201,4199,4200,4198,4169,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.6,943,SUCCESS
21,2025-01-09 17:53:54,84.169,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54581,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4198,4200,4202,4200,4203,4206,4202,4201,4201,4200,4200,4198,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.6,966,SUCCESS
22,2025-01-09 17:53:58,88.182,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54580,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4198,4200,4202,4200,4203,4206,4202,4201,4201,4200,4200,4198,4169,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.7,941,SUCCESS
23,2025-01-09 17:54:02,92.191,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54581,17,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4200,4202,4200,4203,4206,4202,4201,4201,4200,4200,4198,4169,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.7,948,SUCCESS
24,2025-01-09 17:54:06,96.202,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54579,15,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4200,4202,4200,4203,4202,4202,4201,4201,4203,4200,4198,4169,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.6,936,SUCCESS
25,2025-01-09 17:54:10,100.213,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54581,14,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4200,4202,4200,4203,4202,4202,4201,4201,4204,4200,4198,4169,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.7,938,SUCCESS
26,2025-01-09 17:54:14,104.222,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54580,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4200,4202,4200,4203,4202,4202,4201,4201,4204,4200,4198,4169,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.7,965,SUCCESS
27,2025-01-09 17:54:18,108.235,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54579,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4203,4202,4202,4201,4202,4200,4201,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.7,949,SUCCESS
28,2025-01-09 17:54:22,112.244,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54582,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4203,4206,4202,4201,4201,4200,4200,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.6,941,SUCCESS
29,2025-01-09 17:54:27,116.253,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54582,17,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4203,4206,4202,4202,4201,4200,4200,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.7,981,SUCCESS
30,2025-01-09 17:54:31,120.259,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54588,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4203,4206,4202,4202,4204,4200,4200,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.8,959,SUCCESS
31,2025-01-09 17:54:35,124.269,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54587,17,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4202,4200,4203,4206,4202,4202,4207,4200,4201,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.7,946,SUCCESS
32,2025-01-09 17:54:39,128.270,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54590,15,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4203,4206,4202,4201,4207,4200,4200,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.7,979,SUCCESS
33,2025-01-09 17:54:43,132.275,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54588,15,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4203,4207,4202,4201,4207,4200,4201,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.7,1019,SUCCESS
34,2025-01-09 17:54:47,136.287,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54588,16,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4203,4207,4202,4202,4207,4200,4200,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.8,974,SUCCESS
35,2025-01-09 17:54:51,140.298,0x0701,300,10,0x6001,0,65535,65535,1,29.0,54588,15,16,100,95,95,5926,6300,65535,65535,1403,3520,54600,0x0080,1,3629,100,0x0107,0x1002,0x08,0x08,0x10,0x0230,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,4197,4201,4201,4200,4203,4206,4202,4202,4207,4200,4201,4199,4170,0,0,0,29.0,28.6,29.0,29.0,-273.2,40.8,948,SUCCESS


    Best Regards,
    Noel Binny Abraham

  • 0 in reply to Noel Binny Abraham
    TI__Guru 61456 points

    If XCHG stays "green" then the problem isn't with the AFE/FET driver. If the SafetyStatus UTC bit is set while charging, then the XCHG bit should be "red" and the FET should be off. Your description contradicts how the gauge works. Do you have a screenshot that shows both SafetyStatus() UTC = red and OperationStatus() XCHG = green?

    About VCT: This almost looks like your current thresholds which control the gauge states aren't correct. The gg file indicates that the thresholds are correct but the log file doesn't (and this will also have an effect on UTC because UTC is disabled if the current is less than the charging current threshold).

    Are you letting bqStudio auto-detect the gauge without manual action (i.e. you are not selecting it from a list of bq78350 gauge FW versions)? 

  • 0 in reply to Dominik Hartl11
    Intellectual 535 points
    Dominik Hartl11 said:
    Do you have a screenshot that shows both SafetyStatus() UTC = red and OperationStatus() XCHG = green?

    Note: The CHGIN and CHGSU bits are disabled under fet options in this case (Same as previous cases sent above)

    Protections B:


    Before UTC Condition:


    After UTC Condition:



    I got the UTC to work, but this was done by enabling the CHGIN and CHGSU bits from the fet options (Under Settings in Data memory). But as per the TRM this i snot necessary right? We use the BQ40Z80 for another application and in that, the UTC and UTD cut-offs work without the enabling of CHGIN and CHGSU (Not comparing, but just stating our observations)

    Also we tested the UTD as well, and observing the same problem of Fet's not turing off:

    Before UTD condition:


    After UTD conditon:

    (Note: Here XCHG is set because the CHGIN and CHGSU bits are enabled under fet options)

    Dominik Hartl11 said:
    The gg file indicates that the thresholds are correct but the log file doesn't (and this will also have an effect on UTC because UTC is disabled if the current is less than the charging current threshold).

    Here, the log file sent is for end-of-charge cycle (Constant Voltage (CV) curve) as mentioned above. That is why the current is low in the log.

    Our CHG threshold is 500mA and DSG threshold is 100mA. 
    Our taper current set it 750mA. So for the VCT condition of 2* 40sec cycles, maybe the current changes from 750 to 500mA in less than 2* 40 sec cycle? Can this be the issue? This should be solved by bringing down the CHG threshold right, if in case this is the actual issue.

    Dominik Hartl11 said:
    Are you letting bqStudio auto-detect the gauge without manual action

    Yes, the gauge is being auto-detected by BQstudio.

    I know it's a lot of information in a single thread Sweat smile. Do take your time to review and get back with an update.

    Thanks and Regards,
    Noel Binny Abraham

  • 0 in reply to Noel Binny Abraham
    TI__Guru 61456 points

    About VCT: The gauge doesn't use the exact same average current as for the gauging algorithm (the TRM doesn't explain the exact mechanism). The gauge uses a slow (configurable)1st order IIR filter for gauging (and reporting) but a simple averaging (not configurable) of passed charge over a 40 second (default) window to calculate an average current and this has to be <= Taper Current. What this means is that if you set the Taper Current to a value that is borderline (for example, the charger stops when current reaches Taper Current), the gauge may not have qualified this current as the average passed charge / 40s doesn't qualify for the threshold. TI's recommendation is to set the Taper Current parameter 10% higher than the actual current when the charger stops. This usually resolves any problems with VCT at the expense of a slight over-charge (usually negligible <1% capacity).

    The other main reasons for failing to detect VCT is if the quit current threshold is higher than the taper current threshold (=the gauge exits charging state before the VCT conditions are met) and for systems with very small currents, the minimum passed charge requirements for each 40s window.

    Because the current that the gauge uses for VCT isn't reported in the log file, it's not possible to know exactly if the average passed charge over a 40s window / 40s fulfilled the VCT requirements in borderline cases, hence the recommendation to set the Taper Current 10% higher.

    About CHGIN: This controls inhibiting charging based on temperature. This is a bit confusing because it's a separate feature from protection (e.g. UTC) so if you observe that the CHG FET gets turned off if CHGIN = 1, then you observe the action from a different feature (the charge control temperature inhibit range), not the protector.

  • 0 in reply to Dominik Hartl11
    Intellectual 535 points
    Dominik Hartl11 said:
    then you observe the action from a different feature (the charge control temperature inhibit range), not the protector.

    Understood. Then again, I am still not able to get a cutoff for UTC (With CHGIN and CHGSU disbaled [XCHG remains 0 in this case]) and UTD condition with the set protection values.  

    UTC:


    UTD:


    UTC/UTD cutoff and VCT triggering are the major problems that i am facing with the BMS board right now, we really want to get the board into production as soon as possible and were hoping to get these problems solved.

    VCT:

    Dominik Hartl11 said:
    , hence the recommendation to set the Taper Current 10% higher.

    Out taper current as mentioned above is 750mA and the CHG quit current and CHG current threshold both are at 100mA. So even the 10% recommendation is being satisfied here in this case. Additionally, these are the settings that we are currently using for SOC flag configuration just for your info:


    Will you be able to hop on an online meeting with me and my team so that we can show it to you live and maybe that will help you get a better idea and help us troubleshoot the issue? Will this be possible?

    Thanks and Regards,
    Noel Binny Abraham

  • 0 in reply to Noel Binny Abraham
    TI__Guru 61456 points

    Your screenshot for UTC still shows that charging is suspended (SU = 1). Please disable charge suspend.

    About VCT: I checked your log files again. It's not possible to know the exact passed charge within a time window because the gauge doesn't export this particular internal measurement. However, if I calculate the passed charge for a 40s window after both voltage and current meet the charge termination requirements, it's always significantly less than 1mAh. The theoretical minimum required is 0.25mAh. Would it be possible to increase the taper current to 150mA just for a test if this catches a charge termination?

  • 0 in reply to Dominik Hartl11
    Intellectual 535 points

    Hi Dominik,

    Dominik Hartl11 said:
    UTC still shows that charging is suspended (SU = 1). Please disable charge suspend.

    UTC with CHSU and CHGIN disabled:


    Settings:

    (Here the CHSU and CHGIN  bits are disbaled under settings, but as soon as i take the guage to UTC condition, the SU bit sets to red as seen in first image) 

    Regarding VCT: Can you please elaborate on how you calculated the charge accumulated? According to our calculations (we extrapolated it lineraly) , to fulfil the minimum requirement of 0.25mAh an average of 22.5mA should pass through the gauge for a period of 40 seconds. Looking at the log attached to this thread, I believe that after the necessary conditions were met, the average current flowing through the gauge for two consecutive 40-second periods is much greater than 22.5 mA. I understand that the gauge does not export the particular value for current it uses for internal measurement, but it shouldn't be much different than the value we are witnessing in the log.

    The battery is a 13S Li-Ion battery and as seen in image, at a voltage of 53.2V (Full charge is 54.6V and 4.2V/cell) the SOC % is 61% which is not even close to being right. This is why we need to get that VCT problem solved.

    Dominik Hartl11 said:
    Would it be possible to increase the taper current to 150mA just for a test if this catches a charge termination

    We started with a taper current of 25mA (which is scaled by a factor of 10 so it becomes 250mA) and since it did not work, we moved it to 50 mA and then 75 mA. Would the current scaling play any part in this non-triggering of VCT?

    Thanks and Regard,
    Noel 

  • 0 in reply to Noel Binny Abraham
    TI__Guru 61456 points

    About the taper charge: This is the actual taper charge before scaling.

    Please use the .bqz file from this zip file: 1E9B_3_00-bq78350R3_MinPassedCharge.zip

    Copy the .bqz file to the Config folder from bqStudio (remove the original 1e9b_3_00-bq78350R3.bqz file). This version has the Minimum Taper Charge parameter exposed in Data Memory -> Advanced Charge Algorithm -> Termination Config.

    Set this to 1 instead of 64 to effectively disable this limit (for testing purposes). Note that this is in units of 1/256 mAh so 64 = 64/256 = 0.25mAh.

  • 0 in reply to Dominik Hartl11
    Intellectual 535 points

    Hi Dominik,

    We did try with this file and now we have achieved VCT. So do we always use this file now, during configuration and set the Min Taper to 1? 

    Also, we are still having the issue with turn-off during UTC/UTD. Still not able to figure this out. We have a few other same boards and we tested the same using these and the result comes out to be the same.

    Best Regards,
    Noel Binny Abraham

  • 0 in reply to Noel Binny Abraham
    TI__Guru 61456 points

    Please set min taper to 1 (or the smallest value that works in your system).