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BQ35100EVM-795: Inquiry regarding BQ35100EVM-795 test

Grady Lee
Genius 4205 points
Part Number: BQ35100EVM-795
Other Parts Discussed in Thread: EV2400, BQSTUDIO, BQ35100

Tool/software:

Hi, TI expert

Customer have some questions while testing BQ35100EVM-795.

First, I successfully ran bqStudio through BQ35100EVM and EV2400 to connect to the EVM board.

Next, I would like to conduct a test to measure the battery usage using EOS mode.

Q1) When using EOS mode, it seems that the usage is checked by measuring the change in the internal impedance value of the battery. Can you tell me the exact measurement method?

Q2) When setting the EOS mode and applying the NEW Batt setting, when should I run GUAGE_START and GUAGE_STOP?

Q3) How can I check the actual measurement values ​​(voltage, current, SOH, etc.) of BQ35100 in bqStudio?

Below are some questions customer have during the test.

4) Also, since bq35100 is for special batteries, can you explain how the current gauge and the general gauge for the battery used by the customer are different?

The battery is 3.6V and can be used up to 90%, and its capacity changes depending on temperature and current.

5) I wonder why BQ35100 came out for a specific battery, and does it compensate only for temperature or current?

6) There is no part that determines the total battery capacity, and can it just monitor the simple current amount? Can you tell me the exact mechanism?

Technical Spec of ER26500_C.PDF

Technical Spec of ER34615_D.PDF

Please check. Thank you.

  • 0
    TI__Mastermind 26395 points

    Hello Grady,

    This question has been assigned and we will reach out to you when we find the answer.

    Thank you,
    Alan

  • +1
    TI__Mastermind 26395 points

    Hello Grady,

    1- We can't give the exact information out due to it being part of TI battery gauge technology but attached a video on "End-of-service" determination algorithm

    The End-of-Service Determination Algorithm:
    https://www.ti.com/video/5838359925001

    2-Can you specified what you are referring to "GUAGE_START and GUAGE_STOP" I couldn't find these commands in the technical reference manual.

    Technical Reference Manual:
    https://www.ti.com/lit/ug/sluubh1c/sluubh1c.pdf?ts=1743107015324&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FBQ35100

    3-You can view ram data in the register tab.

    4- The BQ35100 gauge uses End of service monitor which emphasize the voltage at the end of the OCV curve but current gauges uses impedance tracking algorithm that can get high accuracy on the entire OCV curve and are more accurate on the end of the OCV curve.

    5-  BQ35100 seems to be specialized for lithium chemistry which is a very popular, reliable and robust cell chemistry to use and every gauge compensate for temperatures and current but different algorithms process them differently.

    6- There is some confusion on the wording of the question, can you explain what you meant to say

    Thank you,
    Alan

  • 0
    Prodigy 20 points

    Dear TI Expert.

    Hello, I am customer of Grady.

    I have some questions for your answer and algorithm of EOS mode.

    [1. EOS Algorithm]

    Q1. The video mentions that the battery condition is evaluated using learning pulses, such as discharge-after-charge and charge-after-discharge. Since we are using a primary lithium battery that cannot be charged, is the EOS mode not applicable in our case?

    Q2. In the section about internal resistance measurement, is the "learning pulse" mentioned here different from the one described in Q1?

    Q3. In the pulse-triggered method, does the main system trigger the pulse via I2C by using the GAUGE_START and GAUGE_STOP commands?

    Q4. The video states that the algorithm uses about 1–2% of the total battery capacity. Does this refer to the entire amount required for multiple learning pulses, or just for the initial learning pulse?

    Q5. If the main system is configured to draw high current (e.g., for wireless communication) every hour, would changing the automatic trigger period (e.g., from several weeks to one month) affect the accuracy of the algorithm?

    [2. Configuration and Register Settings]

    Q1. When should we use the GAUGE_START and GAUGE_STOP commands for data logging? For example, should we trigger it right after a new battery is connected, or before a high current event like wireless transmission?

    Q2. Could you explain the EOS Trend Detection setting in more detail? Specifically, what criteria are used to differentiate between the short-term and long-term averages?

    Q3. The “New Batt R Scale Delay” command is described as determining how many initial measurements are ignored. Are these ignored measurements related to DRD (Direct Resistance Determination) or RSD (Resistance Slope Determination)?

    Thank you for your support!

    Best regards,
    Donggyu Jang

  • 0 in reply to ?? ?
    TI__Mastermind 26395 points

    Hello Donggy,

    We have received your question and need some time to give you a response.

    Thank you,
    Alan

  • 0 in reply to Alan Frias
    TI__Mastermind 37761 points

    Hello Donggyu,

    Sorry for taking a while to get back to you. What specific chemistry are you wanting to use? EOS mode is ideal for Lithium Thionyl Chloride batteries.

    Regards,

    Adrian

  • 0 in reply to Adrian
    Prodigy 20 points

    Hello Adrian. 

    We are using Lithium Thionyl Chloride(LiSOCl2) batteries from EVE.

    Please feel free to contact us if you have any further questions.

    Best Regards,

    Donggyu Jang

  • 0 in reply to ?? ?
    TI__Mastermind 37761 points

    Hello Donggyu,

    These batteries are compatible with the EOS mode on the BQ35100.

    I would recommend reading over this document: https://www.ti.com/lit/an/sluaal7/sluaal7.pdf

    Regards,

    Adrian