WEBENCH® Tools/BQ78350-R1: bq78350-r1

Hi Pavani,

Are you using an EVM or another board? A new EVM should not be sealed. If someone has sealed the device and updated the unseal key, you will not be able to unseal the device without knowing the key.

Regards,

Matt

thank you sir for your fast response..

but new EVM is not sealed sir..,we have given the unseal key and now the device is active.

when we are giving commands in data memory its warning us like this sir "operation failed because initial read of all dataflash failed" whats the problem.could you please help me

Pavani,

Okay, I thought your original message said the device is sealed. Are you following all of the steps in the Gauge Quick Start section of the EVM User guide? Make sure you have pullup jumpers installed on the SMBus pins, make sure you have the correct voltage at the BATT+ and BATT- terminals, make sure you have the shunts installed that connect the AFE and the gauge, and verify that you have pressed the Boot button on the board. If you still have problems, please send a picture of your setup showing the EV2400 and the EVM.

Regards,

Matt

thank you so much for answering my query..

we are getting the correct voltage near BAT+ AND BAT- terminals sir when checking with the multimeter..what is meant by "installing shunts" sir .by the way i will upload our setup images..so that you can help us in a better way..when we connected the very first time that was our setup and the screen appeared to be like that sir..,we did not give any external supply (2.5v).

from the second time the AFE companion bq76940 is not communicating with the hos controller i.e bq78350_r1..so we started giving external supply i.e 2.5v..i will be glad providing you the images of our setup so that you can better understand our query. the yellow coloured circle values are different from the previous uploaded images.could you please help in finding where is the mistake..thanks in advance.

Hi Pavani,

I think you are missing an important step that might be causing some of the issues you are observing. You need to configure the BQ78350-R1 AFE Cell map to tell it how many cells you are using in your system. See below from the EVM User Guide.

thank you sir..

anyways we have executed that step also. if not how will we get all the cell voltages in the registers view.

i think it will be better if we restart the procedure again..though we are restarting we are automatically getting the stored data of bq78350_r1. how can we erase the previous data in BQ78350_R1 IC sir.

thank you sir..,

i have another doubt ,i will be glad if you solve it.

we have charged our set up and applied liteload then the charging and discharging MOSFETs were ON and we left the whole night .now the batteries got discharged and the MOSFETs were OFF.

now my question is,again when we charge the batteries,the MOSFETs must ON directly..,but they are not ON,should we load the program everytime when discharged or is there any alternative for this.

Hi Pavani,

You need to determine why the FETs are off. If the battery cells are in an under-voltage condition, this should turn off only the DSG FET. If both FETs are off, there may be a different reason. You should read the status bits on the register screen to see if other faults have been triggered and understand why.

One thing that might be helpful in your debug is to use the 'Start Log' button on the Registers screen in BQStudio. This will log all of the register settings and voltage/current/temperature measurements while the battery is discharging so you can see exactly what is happening.

Best regards,

Matt

thank you sir..,

actually our project needs cell balancing and monitoring ..could you please help us what are the settings we need to set for the complete project since BQstudio software consists of 1000+ settings we are getting confused.

one more thing wanted to know about the charging and discharging limits for Li-ion (LiFePo4) 48V,2500Ah battery ?

Hi Pavani,

I'm sorry, I cannot walk you through all of the settings for your system. As you said, there are many configurable parameters - you need to refer to the documentation and determine which parameters you may want to modify from the default values based on your system.

The app note Using the BQ78350-R1 will help guide you through the first steps in setting up the device for your battery. The process will be the same for Li-ion and LiFePO4. After you configure the ChemID and find the optimal CEDV parameters, you can look through the other settings in BQStudio. The default values for the voltages are based on a Li-Ion battery (for example, the over-voltage and under-voltage protection levels), so you should modify these values based on your LiFePO4 battery specifications. Each battery is different, so you need to refer to your battery specification.

Best regards,

Matt

ok sir..thankyou

actually our project is cell balancing and cell monitoring system.so what are the complete  settings required in the BQstudio. could you please help me regarding this sir.

and one more,what are the charging and discharging (current,voltage) thresholds for 48V,2500Ah battery Li-ion(LiFePo4).

     Pavani

ok sir thank you,

what are the charging and discharging (current,voltage) thresholds for 48V,2500Ah battery Li-ion(LiFePo4).

     Pavani

Pavani,

You need to refer to your battery specification to determine the thresholds and also you need to consider your application use case for some of these parameters. I cannot determine these settings for you. As I said before, each battery is different.

Regards,

Matt

sir,

during the CC offset calibration we have to make current flow zero. that means current through sense resistors is zero.then in the registers view current in first column must also read zero. but when we are refreshing prior to calibration its showing different values rather than zero.why? in datamemory-->calibration-->current offset ..what is this related to? are these both related?

could you please explain me what actually that current is and why its changing randomly.

thankyou

Hi Pavani,

You are likely observing some noise. The LSB of the voltage across the SRP and SRN pins is 8.44uV, so you should expect this current to vary a little. You should go ahead and calibrate the offset (with no current load) and then the gain (with a fixed load).

Best regards,

Matt

THANK YOU SIR..,

though we are calibrating and our battery is in healthy condition ,the CHG and DSG FETs and not turned ON continuously. they are ON and OFF randomly. 

what is the reason.

Hi Pavani,

The FETs should not turn on and off randomly. You will need to find the reason. Make sure you have sent the FET_EN command as instructed in the EVM User guide. Observe the status bits on the register screen to determine if any faults are present. The FETs will open in response to different fault conditions.

Matt

ok sir thankyou...,

what is meant by SEAL and SHUTDOWN of a device.are those both commands same in operation if not what is the difference between those commands?

when to use those commands. what is the advantage of using those commands.

thanks in advanvce.

Hi sir,

on refreshing the registers view ,voltage in the gauge is not continuously reading the values. but current value is being refreshed and reading correct value. why voltage value is not refreshed?

thank you

thank you sir,
    what is the status of FET_EN, DSG TEST,CHG TEST,and PCHG bits when the device is functioning. which of these bits must be high and which must be low?

thanks in advance.

Pavani

we already referred user guide and also TRM but we didnt understand ,thatswhy we are seeking for your advice.what does this mean? only FET_EN bit is high but the CHG and DSG FET bit are not high in the registers view. so i asked you what is their status when in functioning.

thanks in advance.

Pavani,

Please post a screenshot of your BQStudio Register view. If you have followed the steps correctly, CHG and DSG bits should be high indicating that each of these FETs is on. If they are off, there could be multiple reasons.

The reason I say to please refer to the user guide is because we have covered many topics in this thread - SEAL/UNSEAL, Shutdown, FET_EN, setting the AFE Cell Map, how BQStudio Dashboard and Register refresh work, and the definition of several register status bits. Maybe instead of asking about each of these items individually (since the answers are in the documentation), it would be better if you explain in more detail what you are trying to do and what issue you are running into. This way I can help you work through the issue more efficiently. 

Is the main issue that you are still not able to see the FETs successfully turn on? 

Thanks,

Matt

THANK YOU SIR,

actually process is ,according to user guide FET-EN must be set and CHGTEST and  DSGTEST bits must also be set but in our registers view only FET-EN bit is set and CHGTEST ,DSGTEST bits are not set. is this correct?

one more issue is ,when we want to ON the CHG FET ,it is not ON because the FET-EN bit is already set. when we disable the FET-EN bit and give CHG toggle command in commands view then the CHG FET is ON .similarly happens with DSG FET also.

i already told you sir about our project for cell balancing and cell monitoring system with some additional features.

by the way it is always difficult to contact here and wait for the answers sirs,can you please provide your mobile number so that we could contact you directly and it doesnt waste our time.

 thanks in advance sir

Pavani.

Pavani,

I think you have misunderstood something. CHGTEST and DSGTEST are not mentioned in the EVM User Guide. These are special commands for FET testing during manufacturing. You should not need to write to these bits.

The FET_EN command in BQStudio (sends ManufacturerAccess Command 0x0022) enables the CHG and DSG FETs. Writing this command again disables the FETs. The FETs can also be disabled if there is a fault condition. The SafetyStatus registers indicate if any faults are present.

We cannot give out our phone numbers on the forum. You can reach out to your local TI sales representative if you need support beyond the forum.

Regards,

Matt

HI sir,

could you please list out some of the reasons why the cell voltages1...15 cannot be updated continuously ?actually will they refresh continuously and update the values in the sbs cmd or not? and reasons for communication problem between bq78350-r1 and bq76940 ?we are not finding any valid reason sir and not knowing whether it is our mistake . will be glad if you let us know it.

moreover,we noticed a point ,we are able to read the extavgcell voltage continuously.if it is communication problem why will this reading be updated. up-to our knowledge.

thank you.  

how to enable the ADC in bqstudio software. as there is a provision of enabling ADC_EN in bq76940evalsoftware.

thank you sir,

as mentioned in the TRM there are two ADC's one measures current ..,in our application current measurement is continuously reading .the second delta-sigma ADC which measures the individual cell voltage and temperature measurements ,which our gauge is not measuring. what could be the problem? are we missing any bit to set to measure the cell voltages and temperature?

i think it would be helpful if i post our srec file.BMS 4-9-19.gg.csv

Pavani,

Earlier in this thread you sent me BQStudio screen shots showing that the device was measuring the cell voltages. What has changed? Are you now using different hardware?

Matt

same hardware sir.there's no change.

those screen shots which i posted before was ,only when the pack is connected for the 1st time then only cell voltages are read and displayed .they are not continuously reading.what might be the problem?

Hi Pavani,

I'm not sure what the problem is. If you click the read all button on the Registers screen, the voltages should update. If you click the 'Scan' button on the Registers screen they should update continuously. 

Matt

how can we solve this problem sir? as u said we performed everything but still not knowing the mistake .please guide us regarding this.will post our registers view and srec file.already posted our srec file ,is that everything correct or any changes to be done?7th li.gg.csv

Pavani,

I think you need to replace the IC since it has stopped behaving normally. The behavior you describe seems to indicate the IC is no longer working and may have been damaged.

Regards,

Matt

Sir,

we have set the CUV Threshold:3500mv recovery :3800mv. but when we have connected the load and started discharging the battery pack, even when one of  the cell voltages is dropped to 2600mv ,FETs are not turned OFF . and the system is not going to protection mode. why? but in TRM pg.no 21 section3.2 represents that it should detect the fault and doesnt allow further discharge. 

similarly COV protection is also not detecting. what might be the reason ?

thanks in advance.cuv 19.gg.csv

Hi Pavani,

Your data flash file does indicate that both CUV and COV events are being detected. Are you sure that the DSG FET is not turning off during CUV? The best way to debug this would be to collect a log file (click Start Log on the BQStudio registers screen). This will show the status bits of the BQ78350 during the event.

I do see some strange settings in your data flash (not related to CUV/COV):

- Dod at EDV2 is set to zero. This should be set to the default value of 15232.

- It is showing that your sense resistor is 86m ohms.Is this your real value or are you scaling?

- 3500mV is very high for a CUV setting. That is close to the nominal voltage for most cells.

Regards,

Matt

thank you sir for your quick response.

i m sure that our DSG FETs are not turned OFF .because the load which is connected is not turning OFF and it is still discharging the cells and the cells are getting damaged. till date we have many damaged cells and we are going on replacing the cells and continuing the testing. upto our knowledge this problem is only due to device not entering the protection mode.

what is that table given ? no of COV  events and last COV event must be same or different? but our events are not same..why sir?

now we have set dod at EDV2 to the default value but still no change sir.

we have set CUV setting as 3500mv because everytime device is not entering protection and cells are going to deep discharge and cells are getting damaged.so to prevent the cells from damaging we have set it to high value.

regards

pavani.

Hi Pavani,

If you need help debugging, please send a log file of this behavior. I cannot help you without this. 

The table is from the .gg.csv file that you sent. The device save Lifetime data - this shows that there have been many COV and CUV events.

Regards,

Matt

theres a PF bit set sir,IFC how to clear this fault. and though our voltages are not less than CUV threshold, the CUV bit is set .how to clear it?

Wed Oct 23 17:28:40 IST 2019

Device Name = bq78350_R1
Firmware Version = V1_03_BLD0022

Design Capacity = 4400
Design Voltage = 3600
Specification Info = 0x0000
Manufacturer Date = 1980-1-1
Serial Number = 0x0001
Manufacturer Name = Texas Instruments
Device Name = bq78350
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
1,2019-10-23 17:28:44,4.002,0x017A,256,0,0x0000,0,65535,65535,1,24.6,51611,528,622,100,100,95,4144,4144,65535,65535,0,0,0,0x4890,16,0,94,0x7A01,0x0000,0x00,0x00,0x10,0x0000,0x0000,0x0001,0x0000,0x0000,0x0000,0x0000,0x0001,4023,4011,4027,4028,4066,4021,4010,4006,4015,4006,3785,3808,3805,0,0,4126,24.7,24.6,24.6,24.6,-273.2,25.1,1003,SUCCESS
2,2019-10-23 17:28:48,8.002,0x017A,256,0,0x0000,0,65535,65535,1,24.6,51611,625,602,100,100,95,4144,4144,65535,65535,0,0,0,0x4890,16,0,94,0x7A01,0x0000,0x00,0x00,0x10,0x0000,0x0000,0x0001,0x0000,0x0000,0x0000,0x0000,0x0001,4023,4011,4027,4028,4066,4021,4010,4006,4015,4006,3785,3808,3805,0,0,4131,24.7,24.6,24.6,24.6,-273.2,25.2,966,SUCCESS
3,2019-10-23 17:28:52,12.003,0x017A,256,0,0x0000,0,65535,65535,1,24.6,51611,759,641,100,100,95,4144,4144,65535,65535,0,0,0,0x4890,16,0,94,0x7A01,0x0000,0x00,0x00,0x10,0x0000,0x0000,0x0001,0x0000,0x0000,0x0000,0x0000,0x0001,4023,4011,4027,4028,4066,4021,4010,4006,4015,4006,3785,3808,3805,0,0,4131,24.7,24.6,24.6,24.6,-273.2,25.2,968,SUCCESS
4,2019-10-23 17:28:56,16.004,0x017A,256,0,0x0000,0,65535,65535,1,24.6,51611,714,671,100,100,95,4144,4144,65535,65535,0,0,0,0x4890,16,0,94,0x7A01,0x0000,0x00,0x00,0x10,0x0000,0x0000,0x0001,0x0000,0x0000,0x0000,0x0000,0x0001,4023,4011,4027,4028,4066,4021,4010,4006,4015,4006,3785,3808,3805,0,0,4126,24.7,24.6,24.6,24.6,-273.2,25.2,1001,SUCCESS
5,2019-10-23 17:29:00,20.005,0x017A,256,0,0x0000,0,65535,65535,1,24.6,51611,842,659,100,100,95,4144,4144,65535,65535,0,0,0,0x4890,16,0,94,0x7A01,0x0000,0x00,0x00,0x10,0x0000,0x0000,0x0001,0x0000,0x0000,0x0000,0x0000,0x0001,4023,4011,4027,4028,4066,4021,4010,4006,4015,4006,3785,3808,3805,0,0,4131,24.7,24.6,24.6,24.6,-273.2,25.2,997,SUCCESS
6,2019-10-23 17:29:04,24.005,0x017A,256,0,0x0000,0,65535,65535,1,24.6,51611,839,699,100,100,95,4144,4144,65535,65535,0,0,0,0x4890,16,0,94,0x7A01,0x0000,0x00,0x00,0x10,0x0000,0x0000,0x0001,0x0000,0x0000,0x0000,0x0000,0x0001,4023,4011,4027,4028,4066,4021,4010,4006,4015,4006,3785,3808,3805,0,0,4131,24.7,24.6,24.6,24.6,-273.2,25.2,980,SUCCESS
7,2019-10-23 17:29:08,28.005,0x017A,256,0,0x0000,0,65535,65535,1,24.6,51611,764,722,100,100,95,4144,4144,65535,65535,0,0,0,0x4890,16,0,94,0x7A01,0x0000,0x00,0x00,0x10,0x0000,0x0000,0x0001,0x0000,0x0000,0x0000,0x0000,0x0001,4023,4011,4027,4028,4066,4021,4010,4006,4015,4006,3785,3808,3805,0,0,4131,24.7,24.6,24.6,24.6,-273.2,25.2,955,SUCCESS
8,2019-10-23 17:29:12,32.006,0x017A,256,0,0x0000,0,65535,65535,1,24.6,51611,787,732,100,100,95,4144,4144,65535,65535,0,0,0,0x4890,16,0,94,0x7A01,0x0000,0x00,0x00,0x10,0x0000,0x0000,0x0001,0x0000,0x0000,0x0000,0x0000,0x0001,4023,4011,4027,4028,4066,4021,4010,4006,4015,4006,3785,3808,3805,0,0,4126,24.7,24.6,24.6,24.6,-273.2,25.2,973,SUCCESS
9,2019-10-23 17:29:16,36.006,0x017A,256,0,0x0000,0,65535,65535,1,24.6,51611,612,704,100,100,95,4144,4144,65535,65535,0,0,0,0x4890,16,0,94,0x7A01,0x0000,0x00,0x00,0x10,0x0000,0x0000,0x0001,0x0000,0x0000,0x0000,0x0000,0x0001,4023,4011,4027,4028,4066,4021,4010,4006,4015,4006,3785,3808,3805,0,0,4126,24.7,24.6,24.6,24.6,-273.2,25.2,949,SUCCESS
10,2019-10-23 17:29:20,40.006,0x017A,256,0,0x0000,0,65535,65535,1,24.6,51611,596,680,100,100,95,4144,4144,65535,65535,0,0,0,0x4890,16,0,94,0x7A01,0x0000,0x00,0x00,0x10,0x0000,0x0000,0x0001,0x0000,0x0000,0x0000,0x0000,0x0001,4023,4011,4027,4028,4066,4021,4010,4006,4015,4006,3785,3808,3805,0,0,4126,24.7,24.6,24.6,24.6,-273.2,25.2,978,SUCCESS
11,2019-10-23 17:29:24,44.007,0x017A,256,0,0x0000,0,65535,65535,1,24.6,51611,593,658,100,100,95,4144,4144,65535,65535,0,0,0,0x4890,16,0,94,0x7A01,0x0000,0x00,0x00,0x10,0x0000,0x0000,0x0001,0x0000,0x0000,0x0000,0x0000,0x0001,4023,4011,4027,4028,4066,4021,4010,4006,4015,4006,3785,3808,3805,0,0,4126,24.7,24.6,24.6,24.6,-273.2,25.2,963,SUCCESS
12,2019-10-23 17:29:28,48.008,0x017A,256,0,0x0000,0,65535,65535,1,24.6,51611,595,643,100,100,95,4144,4144,65535,65535,0,0,0,0x4890,16,0,94,0x7A01,0x0000,0x00,0x00,0x10,0x0000,0x0000,0x0001,0x0000,0x0000,0x0000,0x0000,0x0001,4023,4011,4027,4028,4066,4021,4010,4006,4015,4006,3785,3808,3805,0,0,4126,24.7,24.6,24.6,24.6,-273.2,25.2,1008,SUCCESS

Hi Pavani,

There is a command to clear permanent fails (search for "Permanent Fail Data Reset" in the TRM. Your log shows an SUV permanent failure which means that the AFE under-voltage was detected at some point. The permanent failure must be cleared for normal operation.

In your log, it also looks like cells 11, 12, and 13 are much lower than the other cells. You should figure out why this is happening on your hardware.

Matt

after IFC bit in PF status is set,from then onwards the CUV bit is set though we dont have any cell undervoltage .

how to clear that CUV fault?

To recover from a CUV fault, all of the conditions described in section 3.2 of the TRM for CUV recovery must be met.

If you think you are meeting these conditions, please collect a log file and send it.

Thanks,

Matt

hi sir,

in sec 11.5.1 it is mentioned that when the device is sealed standard SBS functions have access and extended SBS functions do not have access..what are those standard and extended SBS functions? is this the reason for cell voltages not varying continuously? or whether  device reset(sec 17.2.33) is anything responsible for cell voltages not varying?

however we have cleared the problem after changing the IC BQ78350-R1 we have neither RESET nor SEALED the device till now and our board functions are going good. 

now we wanted to know exactly what will happen if SEAL and RESET commands are given.

thank you 

pavani.