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BQ34Z100-G1: OCVTAKEN Flag not being SET after Charge termination.

Chek Castillo
Prodigy 70 points
Part Number: BQ34Z100-G1
Other Parts Discussed in Thread: BQ34Z100

I am currently performing a learning cycle for the following battery pack:

LiFePO4 Battery, 15 in series, 3.2V nominal per cell, 40Ah capacity

After configuring the BQ34Z100-G1, I performed the following learning cycle:

1) Started with a full battery (relaxed for a few hours), IT enabled. After a few minutes, OCVTAKEN toggles high.

2) Discharged battery to terminate voltage, disconnected load. Allowed pack to relax until OCVTAKEN is set.

3) Charged battery until taper current is reached. FC bit is set. Disconnected charger from pack. BQ34Z100 goes into relax mode waiting for OCVAKEN to set.

It has been almost 36hrs but the OCVTAKEN flag is still low. I would like to ask what could be preventing the OCVTAKEN bit from toggling.

At this point the learned status is already at 05 and max error is 3%.

Attached is the gg and log file of the learning cycle. Thanks!

PS: I also tried the learning cycle where the process begins with a discharged battery but the same issue crops up.

Learning Cycle data.zip

  • 0
    TI__Guru* 76230 points
    Hi Chek,
    Update status going to 05 means qmax has already learned. You have already gotten your two dod0 points needed that is why qmax updated. You should proceed to the next step which is the discharge phase using a constant current value between c/5 and c/10 and update status will go to 06.

    make sure you programmed your design capacity correctly based on the number of cells you have in parallel

    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 70 points
    Oh ok. I thought I had to wait for the OCVTAKEN bit to toggle before I move on to the discharge phase.

    As for the design capacity, the pack is only composed of 15 cells in series. I'll try discharging the pack and see if the learned status changes to 06. Thanks!