BQ40Z80: The problem with determining the full capacity

Dmitry Verkhorubov

Part Number: BQ40Z80
Other Parts Discussed in Thread: GPCCHEM

We are faced with the problem of determining the Full Charge Capacity in the bq40z80 chip. When setting the chip, Remaning Capasity and FCC for 5 cells are displayed incorrectly, however, when setting 6 cells, Remaning Capasity and FCC are no longer equal to zero and they are being calculated. Due to the problem of calculating these parameters, State of Charge is always 100%, which leads to incorrect operation of the Terminate Charge parameter.

We did a training process and got updated Qmax and Ra_Table, but the capacity is still not displayed correctly. Please help me solve this problem.5s_FCC-zero.rar

over 4 years ago

0 Nick Brylski over 4 years ago

TI__Mastermind 19195 points

Hi Dmitry,

Has the device been configured correctly for 5 cell? Refer to DA config in TRM.

Best regards,

0 Dmitry Verkhorubov over 4 years ago in reply to Nick Brylski

Prodigy 110 points

Hi Nick,

The configuration was done in accordance with this document:

In the archive that I attached, you can find .gg. Below I am attaching a screenshot of the cell config:

I hope you can help me find the error.

Best regards,

Dmitry Verkhorubov

0 Nick Brylski over 4 years ago in reply to Dmitry Verkhorubov

TI__Mastermind 19195 points

Hi Dmitry,

Can you upload image of all the registers and bit register?

Has the correct chemID been programmed?

Thanks,

0 Dmitry Verkhorubov over 4 years ago in reply to Nick Brylski

Prodigy 110 points

Hi Nick,

We use LG 18650-MH-1 cells. The corresponding CHEM_ID is 2038.

Best regards,

Dmitry Verkhorubov

0 Nick Brylski over 4 years ago in reply to Dmitry Verkhorubov

TI__Mastermind 19195 points

Hi Dmitry,

Refer to Cell Configuration, looks like it is configured for 4 cell. You have it configured for 4 cell.

Best regards,

0 Dmitry Verkhorubov over 4 years ago in reply to Nick Brylski

Prodigy 110 points

Hi Nick,

I was setting cell config according to TRM. By looking at the screenshot above and the screenshot that I am attaching now, you can see this. Also, if I set the chip to 4 cells, then why is it displaying 5 cells, counting Qmax and DOD?

Best regards,

Dmitry Verkhorubov

0 Nick Brylski over 4 years ago in reply to Dmitry Verkhorubov

TI__Mastermind 19195 points

Hi Dmitry,

In the .gg you attached it was configured for 4.

Best,

0 Dmitry Verkhorubov over 4 years ago in reply to Nick Brylski

Prodigy 110 points

Hi Nick,

Here is the new actual .gg. For some reason, the previous file was not exported correctly.

3364.Test_5s1p.gg.csv

Thanks,

Dmitry Verkhorubov

0 Wyatt Keller over 4 years ago in reply to Dmitry Verkhorubov

TI__Guru** 105760 points

Hello Dmitry,

The FCC reported won't be correct until you program in the right chemistry ID (which it looks like you have, but it may be helpful to check using the GPCCHEM tool if the below suggestions don't help)

After you program the correct terminate voltage and design capacity and capacity the FCC should update. I see from your .gg that the terminate voltage is 21V, that looks incorrect to me as this is the voltage the gauge uses to predict FCC and SOC (the terminate voltage is when the gauge will set FCC = 0)

Set the terminate voltage to the lowest voltage for your system, set the design capacity, send the reset command (for dataflash to be set in RAM), the FCC should be updated.

Sincerely,

Wyatt Keller

0 Dmitry Verkhorubov over 4 years ago in reply to Wyatt Keller

Prodigy 110 points

Hi Wyatt,

Indeed, the terminate voltage was not set correctly, thank you for pointing out the error, now everything works.

Best regards,

Dmitry Verkhorubov

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BQ40Z80: The problem with determining the full capacity