• State TI Thinks Resolved
  • Locked Locked
  • Replies 9 replies
  • Answers 6 answers
  • Subscribers 63 subscribers
  • Views 413 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.

BQ27520-G4: how 2 cell profiles are maintained for cycle count

Likhitha Eugene James P
Expert 2270 points
Part Number: BQ27520-G4

Hi all,

I am facing challenge with respect to cycle count.Module says that cycle count will be reset once new battery is inserted but it is not happening so we are manually trying to reset cycle count. but as Ti module says that gauge maintains separate cycle counter for both cell profiles. so to reset it which profile i should reset.

Is it something like i have to reset both the profiles? how will i know which profile is active(cyclecount 0 OR cyclecount 1).Can someone explain that how cycle count memory is mapped with respect to 2 cell profiles.

Thanks,

Likhitha

  • 0
    TI__Guru* 76230 points

    there is a flag called app status that lets you know which profile is active.also, the Ra status and flags let you know which profile is getting updated and being used. the changing values of the tables too can be used to identffy which is being used.

    thanks

    Onyx

  • 0 in reply to Onyx Ahiakwo
    Expert 2270 points

    Hi Onyx,
    Thanks for the response.
    Can you please clarify some of my below queries:
    1. In the module TRM it is mentioned that cycle count will be reset once new battery is inserted. But in my case the cycle count is not resetting. Can you help us to understand why this change in behavior?
    2.If we use the standard command for reading the cycle count from which location (cycle count 1 or cycle count 0) it is reading the data?
    Thanks
    Likhitha

  • 0 in reply to Likhitha Eugene James P
    TI__Guru* 76230 points
    I believe if the gauge uses the default profile instead of one of the two other profiles, then that is when the cycle count will be reset. The default profile is used if the gauge detects the batteries are brand new. See the TRM for details on how the gauge determines which profile to use.
    The command will return the count of which ever profile is being used by the gauge at that point.

    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Expert 2270 points

    Hi onyx,

    Thanks for your quick reply. as you told app status will give the active profile but when I checked It is giving the last active profile. That is not helping out.

    I have 2 doubts:

    1.) I tried second method by checking Ra flag  but I am little bit confused regarding the values. as data sheet says default value will be 0x55 for Ra flag. In my case when cycle count 1 profile is active Ra 1 flag value is 0x00 and Ra0 is 0x55. Can i assume that whichever profile is active Ra flag will be 0x00?

    2) inserting a brand new battery also not resetting the cycle count.it is taking last used profile only. I have experimented with some 4 batteries and observed the cycle count profile used and found that it is always using pack 1 profile. data sheet is telling like profile will be used based on impedance matching but if i am inserting a brand new battery then also why the same profile is getting used(pack1). according to me it should be pack 0. since I have to reset the cycle count manually will it be safe and ok to reset the both cycle count? or we should only reset the active one. what will be the impact if i reset both?

    Can you please clear my doubts.

    Thanks

    Likhitha

  • 0 in reply to Likhitha Eugene James P
    TI__Guru* 76230 points
    1. 00 for flag and 55 for status means it is the active one
    2. cycle count is for informative purposes and doesn't affect anything, so you can reset it manually
    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Expert 2270 points

    Hi Onyx,

    with respect to your first answer I checked in data sheet and it is says that minimum and max value for  "Ra status"  can only be 0x0 and default is 0xFF.

    also i checked the updation of Ra table in that Ra status (Ra0 or Ra1) is always 0x0. now which value i have to check for Ra status.

    Thanks

    Likhitha

  • 0 in reply to Likhitha Eugene James P
    TI__Guru* 76230 points

    ps share your gg file.

  • 0 in reply to Likhitha Eugene James P
    TI__Guru* 76230 points
    Hi
    Update status in all four fields should be 02. Qmax in all fields should be the same. Ra status on just one table should be 00 while ra flag on should be 55 on one. As you use the gauge the gauge will update the rest of the ra flags and statuses as needed

    thanks
    Onyx