• State
  • Locked Locked
  • Replies 6 replies
  • Subscribers 63 subscribers
  • Views 1306 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.

BQ27220: Regarding Calculating CEDV coefficients of Bq27220

Abhishek singh
Expert 2000 points
Part Number: BQ27220

Hi  Team,

We are using above mention gauge in one of application, we are using 6  battery of 3000mAH in parallel, hence the total capacity  of battery is  18000mAh. Now it takes 30  hrs to  completely discharge battery, due to  some voltage fluctuation our temperature  chambers becomes  of and  generated log file is  not useful for coefficients generation. Now  I  have  few  question    

1)  In spite of  using all six cell in parallel can I  use the single  cell at  same load  current to  reduce the time it takes to  discharge.

2)Since we  have problem with maintaining temperature constant,  is it possible to  do something so that we can avoid temperature chamber as we don't  have any other option and this

is only  limiting factor and  we are trying to complete  this since last one  month?     

   

  • 0
    TI__Guru* 76230 points
    Hi Abhishek
    I would hv to look into if it is possible to use just 1p and then scale for 6. But you might want to atleast have the log files for the 1s on standby and ready incase if that is possible.

    Without the temp portion, you will be unable to get optimized results so you have to get your temp chamber to be able to maintain a constant temperature. Most temperature chambers can do this though.

    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Expert 2000 points
    Hi Onyx ,
    yes temprature chamber is able to maintain temp , but due to power fluctuation or some other reasons if chamber shows any error we must acknowledge that befor it starts again , so for thirty hours we have to monitor this which is tough , we tried few times but in every log there is change temp atleast for 15-20 minutes.

    How accurate our gauge will be
    1) without coefficients
    2)with coefficients at room temprature only ie 25 -30 degree
  • 0 in reply to Abhishek singh
    TI__Guru* 76230 points
    without coefficients, it wouldn't be accurate. With coefficients only at room, you will have errors at lower temperatures. We can't place a number on the accuracy.


    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Expert 2000 points
    Hi Onyx
    Any update on generatng cedv coefficients for 1P and then scaling on 6 as discussed above
  • 0 in reply to Abhishek singh
    TI__Guru* 76230 points
    Abhishek,
    It doesn't seem possible at this point. What i would recommend would be to string up multiple loads in series to reduce the amount of time to discharge the cells so you can get a file to submit to gpc tool.
    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    TI__Guru* 76230 points
    Hi Abhishek

    I got some feedback after discussing this some internally. The resistance scale factor "EDVR0" for the 1p CEDV coefficients has to be divided by the number of parallel cells. It is the only value that is multiplied directly by current in the algorithm. The rest of the coefficients should stay the same.
    thanks
    Onyx