CCS/BQ40Z60: abnormal avg time to empty

1. Avg Time to Empty depends on AvgCurrent. 65535 will be the value if the algorithm does not run.

2. You will have to test it for your settings in the bq40z60.

3. Depends on the quit current settings. This will compute to high values only if the gauge predicts a very low current. I have not seen this occur very often.

4. No, the algorithm does not run. you need to test this on an EVM.

5. Once a second.

1, When doesn't avg time to empty algotithm run? Avg current is 0mA?

2, I attach my setting configuration. Could you tell me how charger perform after cell is charged to full?

5504.7_19_6_3 version.gg - Copy.xlsx

3, In our application, quit current is 40mA. How does 'quit current' impact 'avg time to empty'? As I know, quit current is threshold for relax mode.

4, Please tell me why 'avg time to empty' becomes 49020 or 39216? I attach our log file.

Taurus_BBU_FW_1v60_Time-to-empty-errors_73h-highlights.xlsx

Thanks!

Hello Emma,

1. Avg Time To Empty only runs in discharge mode.

2. The reason quit current matters is because we want to prevent entry into relax mode if you want to get Avg Time to Empty readings.

3. The file you attached is corrupted. I cannot see any IVT data. Can you repeat the test with an actual gauge log file?

1, our quit current is 40mA, do you mean that avg time to empty doesn't run and keep 65535 when avg current is -10mA(FG is in relax mode)?

2, How often does avg time to empty update?

3, The log file is from BQ lof file indirectly. I highlight useful data in YELLOW. Could you help analyze this log, and tell me why this problem happen? Sorry i don't have chance to test using FG internal log. I can simply describe this log to you. avg time to empty varies 49020 or 39216. At the same time, current() is still 0.00A. Gauging status becomes 5A. State of charge keeps 100%. What else information do you need?

from this log and statement you said, 49020 only happens in discharge mode that mean current() is below -40mA. However, actual current() in log is still 0.00, which doesn't match what you said before.

Could you tell me why ?

Taurus_BBU_FW_1v60_Time-to-empty-errors_73h-highlights (1).xlsx

4, I also want to know charger action after cell is fully charged. Are both FET for charger open? What configuration impacts charger performance after fully charged? how?

Thanks very much!

1, our quit current is 40mA, do you mean that avg time to empty doesn't run and keep 65535 when avg current is -10mA(FG is in relax mode)?

2, How often does avg time to empty update?

3, The log file is from BQ lof file indirectly. I highlight useful data in YELLOW. Could you help analyze this log, and tell me why this problem happen? Sorry i don't have chance to test using FG internal log. I can simply describe this log to you. avg time to empty varies 49020 or 39216. At the same time, current() is still 0.00A. Gauging status becomes 5A. State of charge keeps 100%. What else information do you need?

from this log and statement you said, 49020 only happens in discharge mode that mean current() is below -40mA. However, actual current() in log is still 0.00, which doesn't match what you said before.

Could you tell me why ?

5684.Taurus_BBU_FW_1v60_Time-to-empty-errors_73h-highlights (1).xlsx

4, I also want to know charger action after cell is fully charged. Are both FET for charger open? What configuration impacts charger performance after fully charged? how?

Thanks very much!

Give us some time to take a look here.

OK.

My current() reading resolution maybe not enough only 0.00A. So current() reading and run time to empty() reading can match. When run time to empty() isn’t 65535 after full charge, current() is about -1~-9 mA.

     I found not all boards have this issue and some boards have at different temp.

     078-000-109-02(ACPAG192400064) has this issue at 5C, 25C and 50C.

    078-000-109-01(SN: ACPAG185100139) has this issue at 35C.

Time to full of 078-000-109-02（ACPAG192400056）will become smaller not 65535 after full charge at 50C.

    So I think this maybe one issue about current() reading that maybe not inaccurate because of noise or inaccurate calibration for some batch board. Please give me your advice! Is my thought right? If yes, how to solve this? Doing calibration again or other method? If doing calibration again, please share me introduction or document about how to do calibration(including CC offset, board offset, voltage, current ,temp).