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BQ33100: capacitance learning Not working properly

Karthick M
Prodigy 10 points
Part Number: BQ33100

After sending 0x23 (learning cmd )  learning is started and also completed successfully.  After learning is done capacitance is changed to 50F and (initial and design capacitance is 10F). How to verify  the capacitance in theoretically using the learning graph.

In the below image , How the  points A, B , C and D are plotted ? 

  • 0
    TI__Guru** 105760 points

    Hello Karthick,

    The gauge is constantly measuring voltage and current, so it will have all these data points to do the analysis on.

    The graph has the equations at the bottom used to estimate capacitance. If you are just trying to verify capacitance there are multiple different methods to check the calculation. 

    Sincerely,

    Wyatt Keller

  • 0
    Prodigy 10 points

    Hello keller,
    1. We are having 5 capacitors of each 10F capacitance , so the total  capacitance is 10F (50F/5) ,  After learning the capacitance is increased to 50F , what is the mistake I am doing here ? 

    data flash settings for learning 
    Learn Delta Voltage    1000mv 
    Design ESR , initial ESR, ESR      110ohms
    Design Capacitance , 1st Capacitance , Capacitance    10F
    V Learn Max 10730mv 


    still any other data flash settings are required ? 

    hardware 
    For one capacitor  - 3V , 10F
    Learn load  11.6 ohms resistor 

    2.With respect to my ESR value the learn load resistor value is OK ? 

    3. anything wrong with my V learn max , this needs to be increased ? 

  • 0 in reply to Karthick M
    TI__Guru** 105760 points

    Hello Karthick,

    I'm not sure I understand your configuration, you have a 5s1p pack of capacitors, is that correct? Or are these connected in parallel?

    Have you reviewed the application note on some considerations for the learning process?

    https://www.ti.com/lit/pdf/slua751

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 10 points

    Hello Keller ,
    Yes I have 5s1P configuration and I'm already following the application Note for the learning process . 
    1.And I have one more  doubt  what  voltage value should I need to configure to the V Learn max  with respect to my capacitors( Number of  capacitors all are in series = 5 ,individual capacitor voltage = 3V , Stack voltage  = 3 x 5 =  15V)  ? .
    2.Currently I configured the V Learn max as 10730. It should be 15000mv ?

  • 0 in reply to Karthick M
    TI__Guru** 105760 points

    Hello Karthick,

    It should be set for your max charge voltage, it seems this would be 15V for you. Are you only charging your 3V capacitors up to 2.15V?

    Sincerely,

    Wyatt Keller