bq20z75-v180 update status 0x0A

A Update Status = 0A is very unusual. It would indicate that Qmax has been updated two times, the Ra-table has not been updated and IT is no longer enabled. What learning cycle process did they use?

My customer confirmed that update status of bq20z75-v181 became 0x0D after learning cycle. Normally update status becomes 0x06. What does 0x0A,0x0D,0x0E, mean?

Do you have this Technical Documents?

ThomasCosby said:

A Update Status = 0A is very unusual. It would indicate that Qmax has been updated two times, the Ra-table has not been updated and IT is no longer enabled. What learning cycle process did they use?

My customer confirmed that update status of bq20z75-v181 became 0x0D after learning cycle. Normally update status becomes 0x06. What does 0x0A,0x0D,0x0E, mean?

Do you have this Technical Documents?

Here are the Update Status definitions.

0x00 = Impedance Track algorithm and lifetime data updating is disabled (default).
0x02 = QMAX and Ra table have been updated.
0x04 = Impedance Track algorithm and lifetime data updating is enabled.
0x05 = Ra table updated and Impedance Track algorithm and lifetime data updating are enabled.
0x06 = QMAX and Ra table have been updated and Impedance Track algorithm and lifetime data
updating is enabled.
0x0E = QMAX has been updated with FC set and qualified OCV in discharge and charge. (Added to newer devices.)

0x0D = Occurs sometimes during the learning process, but it should get updated to 0E after the next discharge cycle.

0x0A = I have never seen this one. It looks like IT got disabled.

Thank you for your answer.   

Hey even i got a update status of 0x0A. We use bq20z65r1. You people should find out why this happens, I had to perform the learning cycle completely once again. I finally got update status of 0x0E but after generating golden file and programming it to other board i found out that after enabling IT update status went to 0x06 , but when I charged the battery the cell balancing did not start, does that mean cell balancing will only happen if update status is 0x0E?

Does that mean I have to perform learning cycle on each board so that update status becomes 0x0E and cell balancing starts????

Selva,

Update Status = 0A would mean that IT is not enabled. It should change to 0E, if you send the IT Enable command. Cell balancing is disabled until the Update Status has reached its highest state, so that would 0E in your case. If you set Update Status to 02 in your golden file, then it will be 06 after you enable IT. You would then need a Qmax update before cell balancing will work. You can set Update Status to 0A in the golden file and it would be 0E after you enable IT. We do not recommend doing this, but it is possible.

Tom

Thanks for your quick reply Sir.

Just wanted to know how to achieve Qmax update . Is performing a complete learning cycle necessary for Qmax update? or Can it be achieved by normal charge or discharge cycle ? In our case we do not charge till FC bit is set and may stop discharge before termination voltage is reached in our application, so can a Qmax update occur in such a case??

Also we use a bench-top power supply for charging with CC-CV during learning cycle, we have configured the charge fet to cut off when FC bit is set, so after cut off we immediately remove the power supply terminals even after CHG FET turned off since it may affect the OCV reading taken by gauge? will removing power supply terminals immediately after FC bit is set ensure correct learning?? Is there any other way to do it properly without using a smart charger by only using a CC-CV power supply???

Selva

The gauge just requires a 37% change in DOD (effectively SOC) between rest periods for a Qmax update. Qmax can be updated after a charge or discharge cycle as long as a qualified rest period occurs before and after the cycle. You do not have to fully charge or discharge the pack, but the rest period cannot occur in a disqualified region fo the ChemID that you are using. The Qmax update would be disqualified in that case.

You can leave the charger attached as long as the CHG FET turns off. The important thing is that the cells be allowed to rest, so the device can measure the OCV. You do not have to use a smart charger and a power supply will work for charging.

Regards

Tom

Thank You Sir that was very helpful.

Will get back to you if i get any more doubts or problems.

Hello Sir I have performed cycles on some packs and have some problems

1.When I discharge the pack to CUV threshold the DSG FET turns off which is correct but the CHG FET also turns off why does this happen? CHG FET should be on so that pack can be charged back to normal so why does it turn off

2.I have not used any PCHG or ZVCHG FET so i have set ZVCHG 1 & ZVCHG0 in Confg A  to 1 but still PCHG flag sets? why does this happen?

3.When I charge the cells initially everything is fine but after some time CMTO,TCA,OCHGI flag sets. But nothing actually happens when this sets charging current & voltage is normal only the charging current & voltage display sets to 0 but the CHG FET is ok and it makes no difference to charging

4.When charging the cell balancing flag is set in beginning, but after sometime it tuns off even though the cells have voltage difference in them and the unbalance goes on increasing upto a point where when the charging terminates by primary charge termination there is difference of more than 20mV between cells. I am more worried about this problem since balanced cells is an absolute necessity to get the full capacity of cell.

I have sent the charge log file to you and highlighted rows when CB clears and CMTO sets.

I believe you help me soon with these issues

Regards

Selva 

OK I have found answer to one of my question

3.CMTO is just a charge timeout flag it was set to 10800s so when i charged with more than C/3 it sets but doesn't make any problem since CMTO is not set in Charge fault cfg.

So can I make it to CMTO to 0 or to higher value than 10800??

I also found that cell DOD are 0 for all cells shouldnt that be updated to some value??

Why didnt that happen?? and when will that happen??? 

Also i still not understood why balancing stopped even when cells are unbalanced please answer this question 

I was not aware that CMTO was offered on the bq20z75, but setting it to 0 should disable the feature.

DOD0 should change in rest periods after the cells have rested sufficiently to take a qualified OCV measurement.

Cell balancing is not based on a voltage differential between cells, but on a charge difference. The device monitors this internally and enables the cell balancing FETs to slow down or remove charge from cells with more charge.

Oh sorry I am using a bq20z65R1 device. 

Should DOD values update? if they are 0 is it ok? I have given the cells enough rest period almost one complete day.

How to know that all cells have equal charge during balancing? I can only see the cell voltages and there is quite a difference between them ? How to know the cell balancing is working properly??

And why does the CHG FET turn off when DSG FET turns off by CUV ???

DOD0 should be near 0 when the pack is fully charged.

The bq20z series does not provide as much diagnostics data for ell balancing as our newer devices. The capacity for each cell is monitored internally and I can take more than one cycle to balance the cells. 

The CHG FET should not turn off due to a CUV condition, so there must be another fault or condition as well. 

Thank you Sir.

Can you suggest the newer devices similar to bq20z65.

The bq40z50 is our latest and most high performance device. The bq30z554 is also a good device and it also provides diagnostic information for cell balancing.