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BQ24105-Q1: About FDK Recommend Charging Procedure for Back-Up Batteries In-Vehicle Applications

Part Number: BQ24105-Q1

Hi TI-team

My customer have some question about FDK Recommend Charging Procedure for Back-Up Batteries In-Vehicle Applications

1. There are three different charging procedures depending on the battery voltage.

Even when not using an external MCU, does the BQ24105-Q1 decide which charging procedure to use by itself ?

 

2.Please tell me the content of health check.

In addition, it says "If customer need", how do you set the presence or absence of a health check ?

 

3.Customers are aware that the timer charging method charges at a constant current for a predetermined time.

Isn't the battery voltage checked during charging ?

Even if it is fully charged, will it continue charging until the set time expires ?

 

4.If a temperature abnormality occurs during charging of the timer or the engine is turned off, charging is stopped halfway, and charging is restarted, will the timer be reset ?

Or is the timer counted from the last time ?

  

Best Regards,

Koji Hayashi

  • Hi Hayashi-san,

    Regarding 1, no, the BQ24105-Q1 can only terminate based on battery voltage and termination current.  It needs the mcu and software to decide when to terminate.

    Regarding 2, I suggest consulting the battery vendor to obtain the impedance cut off value for a healthy battery.

    Regarding 3, NiMH battery voltage varies by temperature. At different temperature, the full charge voltage is different. Figure 5 in the app note below shows this.

    Regarding 4, when TS pin detects a temperature fault, charging is suspended but the safety timer does not be reset.

    http://www.ti.com/lit/an/slua843/slua843.pdf

    regards,

    Jeff

  • Hi Jeff-san

    Thank you for response.

    I understand.

    Best Regards,

    Koji Hayashi