BQ27426: BQ27426 SOC is not accurate

Part Number: BQ27426

Tool/software:

Hi,

My customer encountered a problem when using BQ27426.

RD set terminate voltage at 3.3V. Terminate voltage is system shutdown voltage, and also the RSOC 0% relative voltage.

But now when the discharge reaches 3.3V, SOC is still 9%. Then it turns off when the shutdown voltage reaches 3.3V. Plugging in and charging can make SOC normally increase from 0%.

  • Are there any other settings that I can check to see if they are correct? Or any other settings that I can suggest I can adjust?
  •  Does this gauge have a learning function? Will it become more and more accurate after several charges and discharges? And can the accurate profile be taken out and applied?

BR,

Zach

  • Hello Zach, 

    You must do a couple of things before you can expect the SOC to behave accurately: 

    • You must match the chemID you are using by using the GPCCHEM tool
    • You must successfully complete the learning cycle. 
    • You must create the golden image and program this onto the gauge every time it is power cycled or restarted, otherwise the gauge will use the default configuration (which is likely vastly different from your configuration). 
     Does this gauge have a learning function? Will it become more and more accurate after several charges and discharges? And can the accurate profile be taken out and applied?

    Yes the gauge learns the battery parameters as the battery is cycled, but this is a ROM gauge, so every time the gauge is power cycled or restarted, it will revert to the default configuration and you will need to reprogram the golden image. 

    Regards, 

    Jonny.