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Original question:

BQ35100: BQ35100 SOH update time when GE change Low to High

BQ35100: Power-up time and initial measurements

user4867287
Intellectual 435 points
Part Number: BQ35100

Hi,

I use EOS mode.

What is the maximum time from GE high to ALERT low (by INITCOMP=1)?

I measure something near 1800ms, but in an other thread I can read "In the order of < 100 ms".

I need to increase the battery current asap after GE-high. But I do not want to corrupt the initial measurements (OCV after 5 hours of battery relaxation) taken by bq35100.

How important is the initial measurements (relaxed OCV) for the SOH (DOD) and EOS?

Regards

Claes-Henry

  • 0
    TI__Guru* 76230 points
    Hi Claes,

    It is important otherwise the gauge will return EOS_bad_OCV flag.
    The tme for the INITCOMP flag to set around what you measure. Can you point out the thread that says 100ms?
    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Intellectual 435 points
    Hi Onyx,


    Can you specify a maximum time from GE to INITCOMP=1?

    The <100ms information can be found in thread "BQ35100: BQ35100 SOH update time when GE change Low to High". However, important to me is to have a maximum time specified.

    Could you also please respond to my question regarding "How important is the initial measurements (relaxed OCV) for the SOH (DOD) and EOS?".


    Regards
    Claes-Henry
  • 0 in reply to user4867287
    Intellectual 435 points
    Hi Onyx,


    Sorry, I misunderstood your reply regarding OCV.

    I understand that the EOS_bad_OCV flag will be set after a certain number of measurements that are above the initial OCV.
    But I am anxious that the EOS and DOD calculations (battery R) are performed as good as possible. Is the OCV voltage, as measured in the 'Start up Phase', used in the EOS or DOD (SOH) calculations?

    Maybe the calculations of battery R uses the 'update voltage' as measured during the 'Data Update Phase' (R Data Seconds) and not the OCV from the 'Start up Phase'?

    Can TI give any criteria for setting the 'R Data Seconds'? How do I know if the default value of 15 sec should be changed?

    Best Regards
    Claes-Henry Aronsson
  • 0 in reply to user4867287
    TI__Guru* 76230 points

    Hi Claes,

    The initcomp time for most of our gauges is the same. The 100ms in that post is not correct. When the gauge wakes, it performs initialization which involves taking measurements and performing needed initial calculations. 1s is required for measurements and the remainder of the time for calculations. With an added buffer, 2s is the max time.

    When the gauge start command is sent is the critical point for voltage measurement, the cell should be in relax before this command is set. 

    Rdata should be kept at 15s and not changed, that is why there is no explanation on changing it. That is the time the gauge needs to take the needed measurements for the kalmann filter  in the algorithm to function optimally

    thanks

    Onyx