BQ40Z50 problem during learning cycle

>4/ Fully charge the pack; ensure VOK is set at the beginning of charge and FC flag is set at the end of charge

end of charge you can see VCT=1 (Charging status register) or only MCHG?

(VCT - valid charge termination)

The VCT flag should st after charge termination has occurred.

Here is a clarification to the previous post on this string.

We are currently designing a battery pack featuring a bq40z50 configured for 3S. I was doing the optimization cycle as following: (The RDIS and VOK flags do not matter during the optimization cycle.)

1. Configure the dataflash with appropriate parameters suitable for customer's application; configure pack's chemistry and perform calibration.
2. Activate impedance track.
3. Charge the pack to charge termination.
4. Allow the pack to rest until the REST flag sets.
5. Discharge the pack at a C/10 to C/5 rate to the Termination Voltage.
6. Allow the pack to rest until the REST flag sets. Qmax should update and Update Status should increment to 05.
7. Fully charge the pack to charge termination.
8. Allow the pack to rest until the REST flag sets.
9. Discharge the pack at a C/10 to C/5 rate to the Termination Voltage.
10. Allow the pack to rest until the REST flag sets. The Ra table should update and Update Status should increment to 06.

The RDIS flag does matter during discharge after the optimization cycle has completed and it is probably due to a poor ChemID match to your cells. You can send a discharge cycle log file and we can check it with a Mathcad program.

Hi Thomas, thanks you for recomendations..

I'am attach two screenshot:

Today after end of charge, I can't see flag VCT set, charge is switch off aprox ~550-600mA (default Taper current 250mA):

the same pack yesterday successfull clear all CF flags and I see in Data memory:

Gas Gauging,State,Update Status,0e,-

>The RDIS flag does matter during discharge after the optimization cycle has completed and it is probably due to a poor ChemID match to your cells. You can send a discharge cycle log file and we can check it with a Mathcad program.

ok. I make discharge cycle with log

The charging current must drop below the Taper Current for at least 80 seconds for charge termination. If you have a log file and gg file to attach, then I can review them.

Hi Thomas! Thanks you for help!

Last night the pack was successfully calibrated with HWDF=0! Good result!!

I'am try attach log of discharge and gg file.

And I have some questions for new topic about bq40z50..success-pack4.rar

>but the log data shows that the SOC terminating early and the pack is not discharged down to the termination voltage

You told about this setting?

Gas Gauging,IT Cfg,Term Voltage,9000,mV

In my schematic the payload switch off by ~9300mV threshold.

>Can you attach the log file from your optimization cycle

I will try make tomorrow..

Dear Thomas,

Ok, after tinkering here and there and performed another learning cycle with another pack, I was able to complete it without any hitch.

But, right now, I am facing another issue:hoe can I generate the golden file for production? I found instructions from another post saying we need to export the .gg first to change the update status, the we need to write a .senc file to the BQ with the correct chemical ID... But where to find the proper .senc file matching the chemistry we are using (Panasonic NCR18650B cells, Chem ID 0x0210)?

After that, it looks like we need to reflash the .gg file to the BQ, then export the .srec file and perform some modifications on it???

This looks like extremely complicated compared to the BQ27742 where the entire golden file could be generated with a single click...

Is it possible to have a clear explanation on this?

Thank you in advance