bq34z100 ChemID Matching and Qmax Learn Problem with Lead Acid Battery

Allan Fan

Other Parts Discussed in Thread: BQ34Z100, BQ34Z100-G1, BQ34110

Team,

Customer has run the matching process for 6s1p lead acid batterty pack but only get best match ID810 with 17.9% error. I think I need to ship the pack for ID characterization.

Before to get the good ID, they would like to go through learing process to familiar and verify the part first using ID810. They had followed the recommended steps from the post but still can't get it done. Would you please have a look attached log/gg and provide any commends if something might goes wrong? The log start from middle of discharge after 1st OCVTAKEN from FC.

Thanks.

Allan

LeadAcid_TPH12080.zip BQ34Z100_learning log_20161123.zip TPH12080 Specification.pdf

over 7 years ago

0 Damian Lewis over 7 years ago

TI__Mastermind 34665 points

Hi Allan,

We will review the files and get back to you in day or two.

0 Allan Fan over 7 years ago in reply to Damian Lewis

TI__Expert 5730 points

Hi Damian,
Any update?

Regards,
Allan

0 Allan Fan over 7 years ago in reply to Allan Fan

TI__Expert 5730 points

Team,
What does Pb_restart mean? I couldn't find explanation of this.

Regards,
Allan

0 ThomasCosby over 7 years ago in reply to Allan Fan

TI__Guru 73830 points

The PB_RESTART option in the Pack Configuration register is the same feature as the QPCCLEAR in the bq34z100-G1 datasheet. The feature clears Passed Charge that may have been accumulated towards a Qmax update when the gauge exits the relaxation state, if a DOD point has been set. This helps to prevent errors in the Qmax estimate due to the way that PbA voltages relax after charge and discharge.

0 Allan Fan over 7 years ago in reply to ThomasCosby

TI__Expert 5730 points

Tom,

Thanks for explanation. I think I need to enable it for the lead acid battery. After I discharge to empty and relax for OCVTAKEN, the voltage raised and RSOC update to ~20% though I've enabled LOCK0. How can I fix the RSOC to prevent it happen or mask it?

Regards,

Allan

0 ThomasCosby over 7 years ago in reply to Allan Fan

TI__Guru 73830 points

Allan,
LOCK0 will only take effect if the pack is discharged to SOC = 0%. Setting RELAX_JUMP_OK and RELAX_SMOOTH_OK to zero should prevent the SOC from increasing while at rest, but it will jump up when you exit the rest state. The voltage increases significantly after discharge for PbA cells and the gauge will update the RemCap and SOC in accordance with the OCV table. This is how Impedance Track works. We now have a CEDV version of the device available and it should not update RemCap and SOC based on the relaxed state of the cells. It is the bq34110.
Tom

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bq34z100 ChemID Matching and Qmax Learn Problem with Lead Acid Battery