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BQ28Z610-R1: Golden Cycle not successful for 1S4P Pack using bq28z610R1

Jeremy Heath
Prodigy 40 points

Part Number: BQ28Z610-R1
Other Parts Discussed in Thread: BQ28Z610, BQ78Z100

I attempted a Golden Cycle/Learning cycle for a 1S4P battery pack using the bq28z610R1.  It was uncessful for learning the Full Charge Capacity.

Qmax was 14732mAh at the completion of the cycle.
Qmax was updated during the rest periods after Charging (C/5) and Discharging (C/9)
FC was set at the completion of Charging
FD was set at the completion of Discharging
  

Full Charge Capacity (FCC) was 9652 at the end of Golden/Learning cycle.

measured charge capacty: 14.45Ahr
measured discharge capacty: 14.44Ahr


GG File: m_GG_20260115.gg.csv 
Log File: gglog_20260113.log.xlsx 

  • 0
    Prodigy 40 points

    Using "How to Complete a Successful Learning Cycle for the bq28z610/bq78z100" (SLUA777) as a guide, I broke down the steps

    time Description Voltage  Current  FCC VOK Rest FC FD
    1/13/2026 10:37 Start 1st Discharge 3689 -1504 7137 0
    1/13/2026 15:07 FD Bit set 2995 -1507 7137
    1/13/2026 15:08 Learn 2990 -1507 13522 0 0 0 0
    1/13/2026 15:56 End 1st Discharge 2401 0 13522 0 0 0 1
    1/13/2026 19:39 End 1st Rest 2900 0 13522 0 1 0 1
    1/13/2026 20:57 Learn 2910 0 7938 0 1 0 1
    1/13/2026 21:26 Start Charge 3074 1621 7938 1 0 0 1
    1/14/2026 1:26 Learn 4214 1812 12948 1 0 0 0
    1/14/2026 2:45 FC Bit set 4286 289 8368 1 0 1 0
    1/14/2026 2:47 End Charge 4287 276 8368 1 0 1 0
    1/14/2026 3:23 Learn 4268 0 9040 0 1 1 0
    1/14/2026 5:17 Start 2nd discharge 4199 -1502 9040 1 0 1 0
    1/14/2026 14:52 Learn & FD Bit set 2511 -1508 14579 1 0 0 1
    1/14/2026 14:53 Learn 2458 -1508 14606 1 0 0 1
    1/14/2026 14:55 End 2nd discharge 2508 0 14606 1 0 0 1
    1/14/2026 18:07 Learn 2886 0 9652 0 1 0 1
  • 0 in reply to Jeremy Heath
    TI__Mastermind 35125 points

    Hello,

    This question has been assigned within the team and will be reviewed and followed up with a application engineer when possible. In the meantime please attach any associated .log/.gg files associated with the projects

    Thank you,
    Alan 

  • 0 in reply to Alan Frias
    TI__Mastermind 31695 points

    Hi,

    You need longer rest periods in between chg and dsg.

    Regards,

    Diego

  • 0 in reply to Diego
    Prodigy 40 points

    I have 2.5hr rest after charge and 5.5hr rest after discharge.  These time are greater than what is stated in the "How to Complete a Successful Learning Cycle for the bq28z610/bq78z100" (SLUA777) .  For both Charge and discharge, the REST bit is asserted before the time allocated for rest is completed.

  • 0 in reply to Jeremy Heath
    TI__Mastermind 31695 points

    Hi, 

    You need to rest until the required 1uV/s is satisfied for 2 periods of 100s. When this happens, the gauge will take an ocv measurement.

    When I look at the log file, the voltage reading is still fluctuating. 

    Regards,

    Diego 

  • 0 in reply to Diego
    Prodigy 40 points

    From the  "How to Complete a Successful Learning Cycle for the bq28z610/bq78z100" (SLUA777) 

    "The [VOK] and [RDIS] bits in the IT status() register clear once the gauge has taken an OCV reading"

    From the table in the 2nd post and the attached log file gglog_20260113.log.xlsx, the VOK bit is cleared and REST bit is set at:

    1/14/2026 3:23 (after end of charge)

    1/14/2026 18:07 (after end of 2nd discharge)

    Is there another way that the Fuel Gauge indicates that a valid OCV is stored?

  • 0 in reply to Jeremy Heath
    TI__Mastermind 31695 points

    Hi,

    What Chemid are you using? 

    What is the dod% error associated with this chemid match?

    Regards,

    Diego