• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 100 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

BQ27421-G1: fuel gauge battery health is not correct (always ~84% )

BQ27421-G1: BQ27421-G1

Michael Girstmair
Prodigy 20 points
Part Number: BQ27421-G1

Tool/software:

Dear Jonny,

you wrote:

"It is likely that your design capacity is far greater than the actual Qmax reported by the gauge, causing the SOH to read ~84%. "

I think the design capacity should be smaller than actual Qmax report (tor otherwise as you wrote). Finaly the SOH would be only ~84%

I plan to do the following: change the design capacity (470mAh) by scale of 0,84. This would be 470*0,84 = 395mAh. This would mean that the SOH should be 100% if the Qmax reports 395mAh.

Would you also do this experiment or test, or do you think there is something against it?

Thank you for your help and support, best wishes, Michael

  • 0
    TI__Mastermind 24751 points

    Hello, 

    I do not recommend changing the design capacity to a value that is different than what is stated in the cell datasheet. This is because the gauge uses design capacity for other calculations within the gauging algorithm in addition to SOH. My recommendation is to keep design capacity the same, but instead use your host MCU to scale the SOH value reported by the gauge (i.e. scale the SOH reported by the gauge so that 84% reported by the gauge is actually 100% reported by your MCU). 

    Regards, 

    Jonny.