BQ40Z80: 7S problems with already made BMS's

Hello Dmitriy,

Can you log the behavior or is the gauge stopping communication at low RSOC values? Are you triggering any safety events that would cause the gauge to enter shutdown?

Any data you have we can take a look to help debug.

Sincerely,

Wyatt Keller

Hello! 

First of all , i have tried to make learning cycle for my design (7S1P) .

www.ti.com/.../slua848.pdf

And I ran into problems at step 4.2.1, where it was necessary to discharge the battery. After he was discharged, he began to behave like in this topic

https://e2e.ti.com/support/power-management/f/196/t/934553?tisearch=e2e-sitesearch&keymatch=bq40z80 

Naturally, the REST flag was not set, the battery was rebooted all the time and it was not possible to enter UNSEAL. I was able to charge it a little, then I tried to discharge it again and ran into the same problem. After several iterations, I came to a state like in this topic

https://e2e.ti.com/support/power-management/f/196/t/926378 

That is, it shows 65000 millivolts, 8191 Amperes, I cannot make UNSEAL
and I cannot re-upload the firmware. That is, it is a brick. and I already have 2 such batteries.
Circuitry and SREC are attached. The problem is that there are no answers to questions on these problems on the forum,
they were offered to be discussed in private messages, as I understand it.
Plus, the button for indicating the charge level does not work for me,
this problem is described in this topic by me (also closed as solved)

https://e2e.ti.com/support/power-management/f/196/t/914181 

But the battery did not want to turn off, if you turn it on in short-circuit mode,

PDSG_FET began to work constantly, overheating the resistor (that is, the IC rebooted constantly and started to perform PDSG again).

Thus, I do not have to conduct a training cycle, and I do not understand

what my client will have with a battery when charging about zero percent,

since the behavior of the microcircuit is inadequate. As I understand it,

I am not the first person with this problem, and they seem to have been solved.

I am now happy to live with a resistive non-thermocompensated divider on the 7th cell,

but the stability and predictability of the CHG / DSG FET behavior is important to me

I can try on one more battery (I have 32 of them, and remove the log file of what is happening)
Or is there a default log file somewhere in BQstudio?

Of course, i have EV2400 with 0.28 Firmware, Bq studio 1.3.102 and bq40z80  0.04FW

https://drive.google.com/drive/folders/1HMJ72VMIJpQTOLnzRtwUmqBiM10-0Fzq?usp=sharing

Thanks!

Hello,

Can you move to a bq34z100 design at this stage?

The bq40z80 has a watchdog issue at 7S configurations so we have defeatured 7S.

Hello Kang,

is the watchdog issue that thing we had a email discussion at beginning of the year?

And at the end of many emails the cause should be an EOS event?

Thanks for helping us.

Klaus

Hello Klaus,

Yes, we are planning a firmware modification to try and address the watchdog.

Hello Kang,

ok. Thanks for the information.

Hello , Kang ! 

Unfortunately at this stage I cannot change the hardware of the BMS. Everything is already done.

I have to support this hardware.

Therefore, I really hope to get a firmware version with critical issues fixed

(PIN 13 DISP mode, for example) and 7S support.

And another question - what should be done with watchdog so that no reboots occur - disable HWDF?

Thank you!

Hello Kang,again! 

>>Yes, we are planning a firmware modification to try and address the watchdog.

I'll clarify again, just in case - will this update support 7S?

And it's important for me to get a fix for this problem:

https://e2e.ti.com/support/power-management/f/196/t/914181 

Thanks

Klaus, Dmitry,

Kang and I will connect with you offline. I will send a connect request.

Thanks,

Rushi