• State
  • Replies 6 replies
  • Subscribers 63 subscribers
  • Views 56 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

BQ4050: FCC error after one year of use

Carol Lou
Prodigy 20 points
Part Number: BQ4050
Other Parts Discussed in Thread: BQSTUDIO, GPCCEDV

Tool/software:

Hello,

 

We have encountered a strange phenomenon while using the BQ4050.

 

**Background:** 

The BQ4050 is used to manage a 4-series lithium battery pack with a designed capacity of 6600mAh, and the initial FCC (Full Charge Capacity) value is also set to 6600mAh. Approximately 20K units of the product have been shipped.

 

**Issue:** 

Recently, a customer reported that the remaining capacity (RM) when the battery pack is fully charged (100%) is very low, only a few hundred mAh. The customer believes that the capacity has significantly degraded and requested a return for repair. The customer has used the product for 11 months.

 

**Testing:** 

After returning the product to us, testing revealed that the battery cells are in good condition, and the pack can still deliver a capacity of 6300mAh when fully charged. However, the FCC measurement by the BQ4050 was incorrect. We conducted charge-discharge cycles, and each cycle increased the FCC by 512mAh (consistent with the datasheet). After 10 cycles, the FCC has returned to normal.

 

**Inquiry:** 

What could have caused the FCC to drop below 1000mAh? How should we address the customer's complaint?

 

**Note:** 

Out of the 20K units shipped, only this customer has reported this issue.

Could you please help with the issue?

Thnaks very much.

  • 0
    TI__Mastermind 19801 points

    Hello,

    Today is a national holiday. We will get back to you later this week.

    Regards,

    BMS Apps Team

  • 0 in reply to Adrian
    TI__Genius 16270 points

    Hi Carol,

    If possible, can you please share a bqStudio log file of the situation described above, along with the .gg file of the gauge settings on this device?

    Can you also confirm whether the GPCCEDV tool has been used?

    Regards,

    Anthony

  • 0 in reply to Anthony
    Prodigy 20 points

    Hi Anthony,

    Thanks for your reply.

    • I have exported the GG file of one of the batteries (this battery has undergone multiple charge and discharge cycles, and the FCC has been restored). Log file: It has now returned to normal after the charge and discharge cycles. Do you still need it? If so, I will provide it.

    • I confirm that the GPC CEDV tool was used (the CEDV configuration parameters were obtained by uploading six log files to the TI website).BQ4050 LOST FCC.gg.csv

    Regards,

    Carol

  • 0 in reply to Carol Lou
    TI__Genius 16270 points

    Hi Carol,

    If you have a log file of the FCC dropping to the low value before the 10 cycles to restore it, it would greatly assist us in finding the root cause of this issue. In the lifetimes of the .gg file, it says that the gauge temperature is going up to maximum 65 degC. Can you please confirm when this is occurring?

    Regards,

    Anthony

  • 0 in reply to Anthony
    Prodigy 20 points

    Hi Anthony,

    1. The log file where FCC drops to a lower value before recovering after 10 cycles: It's not available now; everything has already recovered.
    2. We set the OTD to 65℃, and based on the Life time data, the issue occurred during the 45th cycle (which happened when the end user was using it).

     Based on the current information, do you have any speculated reasons? Could you provide us with some insights?

    Regards,

    Carol

  • 0 in reply to Carol Lou
    TI__Genius 16270 points

    Hi Carol,

    Understood, thank you for the clarification. Without the log file, it is difficult to pin down the main reason why this is occurring, however the FCC value can be affected by the temperature measurement of the device (typically above 40C) if temperature optimization has not been completed on it. If the device was at that 65C temperature for an extended period of time, then this could of affected the FCC calculation of the device.

    Regards,

    Anthony