BQ28Z610: IT is enabled but RemainingCapacity doesn't change during discharge!!!!!

Hello Batt, thanks for reply....

I do not know how the sw works in detail, then I have set the parameters like I think it is better from the literature and this forum topics.

Due the cells supply a dc/dc converter, the drained power is the most of the time constant then I have chosen Load Mode 1 with Load Select 7 to compensate the load variation (more than 3 times the idle power) when terminal is operating.

I have set the Smooth ON and I do not remember how to reset it :(. In any case, I have understood the smoothing is better to be ENABLED, let me know your opinion.

some gauging and IT parameters are listed below from the initial .gg file upload into the new BQ. FW version is 20.

"Gas Gauging","State","Avg I Last Run","-1500","mA"
"Gas Gauging","State","Avg P Last Run","-540","cW"
"Gas Gauging","State","Delta Voltage","0","mV"
"Gas Gauging","State","Temp k","1.00","°C/256mW"
"Gas Gauging","State","Temp a","1000","s"
"Gas Gauging","State","Max Avg I Last Run","-1500","mA"
"Gas Gauging","State","Max Avg P Last Run","-540","cW"
"Gas Gauging","IT Cfg","Load Select","7","-"
"Gas Gauging","IT Cfg","Load Mode","1","-"
"Gas Gauging","IT Cfg","User Rate-mA","0","mA"
"Gas Gauging","IT Cfg","User Rate-cW","0","cW"
"Gas Gauging","IT Cfg","Reserve Cap-mAh","0","mAh"
"Gas Gauging","IT Cfg","Reserve Cap-cWh","0","cWh"
"Gas Gauging","IT Cfg","Design Resistance","34","mOhm"
"Gas Gauging","IT Cfg","Pack Resistance","30","mOhm"
"Gas Gauging","IT Cfg","System Resistance","0","mOhm"
"Gas Gauging","IT Cfg","Ra Filter","80.0","%"
"Gas Gauging","IT Cfg","Ra Max Delta","15","%"
"Gas Gauging","IT Cfg","Resistance Parameter Filter","65142","-"
"Gas Gauging","IT Cfg","Near EDV Ra Param Filter","59220","-"
"Gas Gauging","IT Cfg","Qmax Delta","5","%"
"Gas Gauging","IT Cfg","Qmax Upper Bound","130","%"
"Gas Gauging","IT Cfg","Term Voltage","3000","mV"
"Gas Gauging","IT Cfg","Term V Hold Time","5","s"
"Gas Gauging","IT Cfg","Term Voltage Delta","300","mV"
"Gas Gauging","IT Cfg","Term Min Cell V","2800","mV"
"Gas Gauging","IT Cfg","Max Simulation Iterations","30","-"
"Gas Gauging","IT Cfg","Fast Scale Start SOC","10","%"
"Gas Gauging","IT Cfg","Min Delta Voltage","0","mV"
"Gas Gauging","Smoothing","Smooth Relax Time","1000","s"
"Gas Gauging","SoH","SoH Load Rate","5.0","Hr rate"

 The DC is 6900 mAh, the load where the conditions were observed was around 750 mA.

I have understood that the effect of late update of the RC is not a wrong behavior, but for users is not good the terminal stay 100% long time then start to decrease a bit faster then the expected.

Can you give me your suggestions for a better tuned set of parameters?

Thank you in advance

Maurizio  

Here the file.

I add also a copy of a screenshot: the value of FFC is clear from 8449-1426-580=6443 but it is correct? I was expecting the true remain q will be scaled to 0 when the charge termination is reached, FD bit set, but like I have told, I do not know the algorithm of the sw. the important is I can pass this strange behavior....

6787.1s3p-cellv0.20.gg.zip

Hello Batt,

still waiting for your analysis, I send you a .gg file taken from a real battery which has performed a few cycles of charge discharge, like you can read.

The previous .gg sent some days ago is the .gg file used to build the golden file: it sets the parameters in a battery pack when the cells are connected for the 1st time.

here the file from the manufactured pack.

Thanks again.....temp.gg.zip

Hi Maurizio,

It would help us to see all of the registers from the fuel gauge and witness the problem in action.

Can you please capture a logs using bqStudio on a good battery and a "bad" battery?  Please capture at least 15 minutes of data, but if you can leave it longer then it's even better.  If you can log overnight it would be best.  Then extract .gg.csv files from each battery you captured a log from and zip the logs and .gg.csv files and attach to a post here for us to analyze.

Hi dMax,

unfortunately I have tried to recover the "bad" battery packs, then I upload the FW again and restarted from the beginning, thinking that something was wrong in the process of those few bad items.

So, currently I do not have strange batteries to extract data like you requested, but be sure I will do at the first item which will show the same behavior.

Thanks for the moment and I will wait the comment from Batt about the setting parameters.

Bye ....

Maurizio

Thanks Batt,

I appreciate a lot your helps that make me more and more confident with the BQ28Z610 and its SW.

I assure you that I have followed the procedure to prepare the golden .srec file which has already prepared after the learning cycle in controlled process.

Your last message has driven me to review the manufacturing process and it could be a lack in the rest period after discharge. Better I explain...

Each new board is uploaded with the golden .srec file, then we calibrate the cell voltage on the board, enable IT and shutdown.

Later we connect the cells (it is 1s3p configuration) and assembly it into the housing.

At this point the cycle is charge full, rest 2 hours then discharge overnight (the current value is about 0.15C, then it is needed 7 hours + 5 hours rest) and charge again to full the following morning (that is after more than 12 hours).

But it maybe that to short the time of manufacturing, the rest period after discharge has not been respected and so, the items subsequently put in charge would present less FFC value and the behavior I described.

Do not think it is so obvious, I have needed your help to understand the possible cause... I work in China, not ever it is easy to communicate with colleagues and subcontractors....

Thanks again, in case I will log a good and a bad item and send you the logs and the .gg files.

Maurizio