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Original question:

BQ35100: Accumulated Capacity

BQ35100: Accumulated Capacity - BIS

Goulwen LE BOZEC
Prodigy 140 points
Part Number: BQ35100
Other Parts Discussed in Thread: EV2400, BQSTUDIO

Hello,

Sorry for the late response.. (old subject   https: //e2e.ti.com/support/power-management/f/196/t/910656)
My issue was the BQ35100 : "on some boards the "AccumulatedCapacity" counter is increase from 0 to 4,29E9 and some times on others/sames boards it's decrease (start at 0 and roll over to 4,29E9) 4,29E9 to 0. (Same hardware, not able to charge the cells)."
And it's still the same.. but i have more informations.

I have manually change the calibration data (CCoffset, DeltaOffset, CCGain, Voffset, BoardOffset) by doing means of them etc.. I did this to get close of the real consumption i had.

I had a power resistance of 3,9ohm, a tension of 3,08Volt.

so : U = RI => I = 3,08/3,9 = 0,933A

the BQ35100 do this things in mAh so i have to convert my result.

I will consume energie during 5 secondes.

so : (nb_sec * mA) / (60*60/1000) = (5 * 933) / 3,6 = 1295 mAh (during 5 sec).

With the calibration by software i was at more than 50% less of the real consumption seen. With manualy upgrade i'm at 10% more than the real consumption.

The real issue is some times with the software calibration, with the same tool of board calibration we have the BQ35100 some times counting or counting down.

BUT with manualy calibration i have seen the same issue but the when the data calibration are "evaluated" by me as 'ok'. I apply them to all my boards and they all counting or counting down.

I know the BQ35100 is counting or counting down when the battery is discharging or when the battery is charging. But any boards and batteries haven't the capacity to charging the batteries.

I don't know if i have been clear on this subject.. feel free to ask me questions !

Regards,
Goulwen LE BOZEC.

  • 0
    TI__Guru** 105760 points

    Hello Goulwen,

    Do you have a log you can share with us so we can take a look? Also if you could share your .gg file, I can load it on one of our EVMs to do testing.

    I think your manual calculation may be incorrect 1295mAh is a lot for a 5 second period.

    It sounds like with either calibration method you use it doesn't determine if the gauge will count down or up?

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 140 points

    Hello Wyatt !

    Do you have a log you can share with us so we can take a look? Also if you could share your .gg file, I can load it on one of our EVMs to do testing.

    - I think i can not share any .gg file. I don't know what is it. (I do not use evaluation board for TI)

    - What do yo mean by EVMs ?

    I think your manual calculation may be incorrect 1295mAh is a lot for a 5 second period.

    - You think well, my calculation is incorrect.. it's not 1295mAh but 1295µAh 

    It sounds like with either calibration method you use it doesn't determine if the gauge will count down or up?


    - Yes that's it

    Regards,

    Goulwen LE BOZEC.

  • 0 in reply to Goulwen LE BOZEC
    TI__Guru** 105760 points

    Hello Goulwen,

    Do you have an EV2400? You can pull the .gg from the gauge with just the EV2400, you don't need an EVM. EVM is the evaluation module.

    Okay that calculation makes more sense.

    I'll need to confirm on my board. If there is some noise on the SRN and SRP lines it may count up briefly and roll-over. With a clean current does this still happen?

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 140 points

    Hello Wyatt,

    Thanks for your fast reply ! It's appreciate.

    Do you have an EV2400? You can pull the .gg from the gauge with just the EV2400, you don't need an EVM. EVM is the evaluation module.

    - I do not have an EV2400.. So I can't do a .gg file ? Can I just tell you how I configure the BQ35100 ?

    Okay that calculation makes more sense.


    - Glad to hear that !

    I'll need to confirm on my board. If there is some noise on the SRN and SRP lines it may count up briefly and roll-over. With a clean current does this still happen?


    - I had this discussion with my co-worker and we conclude this :

    - The noise on the SRN and SRP are not a good way because when I change manualy the calibration data, there is'nt any weird current so there is no disturbing noise ? (Do you agree ?)

    Regards,

    Goulwen LE BOZEC.

  • 0 in reply to Goulwen LE BOZEC
    TI__Guru** 105760 points

    Hello Goulwen,

    I would recommend getting the EV2400 to speed up testing and debug, you can also use the calibration method provided in bqStudio to see if it will yield different gains.

    The .gg file will contain all the values you have configured on the gauge including calibration information, so it's fastest to use that file format because I can directly import it on my side.

    I'm not sure I understand what you mean, how are you manually changing the calibration?

    Sincerely,

    Wyatt Keller 

  • 0 in reply to Wyatt Keller
    Prodigy 140 points

    Hello Wyatt,

    The .gg file will contain all the values you have configured on the gauge including calibration information, so it's fastest to use that file format because I can directly import it on my side.


    - Ok i see but i don't have this tool.. i will ask my boss for it 

    I'm not sure I understand what you mean, how are you manually changing the calibration ?


    - I'm changing this data, I did average for this data on 10 boards then I had fix this data to have less difference between the accumulated capacity return by the BQ35100 and my calcul (first message). (I saw that is a good way to do there : "https ://e2e.ti.com/support/power-management/f/196/p/949789/3509533?tisearch=e2e-sitesearch&keymatch=BQ35100%2520accumulated#3509533" btw that was you ! :) )

      

    Regards,

    Goulwen LE BOZEC.

  • 0 in reply to Goulwen LE BOZEC
    TI__Guru** 105760 points

    Hello Goulwen,

    It would be very helpful to have the EV2400 for debug.

    Can you share the raw hex values from the accumulated charge register?

    On my side I see it starts at 00 00 00 00 and then when I start discharge it starts decrementing from ff ff ff ff. bqStudio interprets this as starting from 0uAh.

    Is it half of your gauges count up and half count down?

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 140 points

    Hello Wyatt,

    It would be very helpful to have the EV2400 for debug.


    - Yes i will see what can i do for it.

    Can you share the raw hex values from the accumulated charge register?


    - See raw hex on the following screen :

    On my side I see it starts at 00 00 00 00 and then when I start discharge it starts decrementing from ff ff ff ff. bqStudio interprets this as starting from 0uAh.


    - Yes i see the same behaviour when the BQ35100 is counting up :)

    Is it half of your gauges count up and half count down?


    - Ok I think my explanations are not clear.. I will try to repeat it clearly ! (sorry)

    So, we have boards on massive production included BQ35100 inside. This boards pass throught a calibration process for the BQ35100 using TI calibration routines. Each board calibration result by a different calibration data (Do you agree ? No far from each other but not exacly the sames).
    By doing this i see the issue i'm talking to you, some times the BQ35100 where counting up and some times down..

    But to face this issue, I did somes "experiences" with the BQ35100. I did average calibration data (and try to get closest result of my calcul, first message) then juste write that data on the BQ without doing the calibration process, write in the datasheet.In fact when i did this all boards with the same calibration data (the average one) they were all counting up or down but all in the same way !

    And my question is "Why some times, for the same discharge current (same board, same way... but differents data calibrations), the BQ35100 is counting up or down ??"

    Do you understand better my issue or not ?

    Regards,

    Goulwen LE BOZEC.

  • 0 in reply to Goulwen LE BOZEC
    TI__Guru** 105760 points

    Hello Goulwen,

    I meant the bytes you're receiving from the gauge when it's counting up vs counting down?

    Is it going from 00 00 00 00 and incrementing up, so 00 00 00 01 next when it's counting down?

    Right, so no matter how you calibrate/setup the gauge it's randomly counting up/down.

    There are several other threads on the forum regarding similar issues, were any of them helpful for you?

    There's one here: e2e.ti.com/.../852417

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 140 points

    Hello Wyatt,

    I meant the bytes you're receiving from the gauge when it's counting up vs counting down ? Is it going from 00 00 00 00 and incrementing up, so 00 00 00 01 next when it's counting down ?


    -  Right, so no matter how you calibrate/setup the gauge it's randomly counting up/down. => Yes, and i don't understand why !?

    There are several other threads on the forum regarding similar issues, were any of them helpful for you ? There's one here: e2e.ti.com/.../852417


    - I'm not sure to understand this..

    Regards,

    Goulwen LE BOZEC.

  • 0 in reply to Goulwen LE BOZEC
    TI__Guru** 105760 points

    Hello Goulwen,

    Can you share the accumulated capacity values collected with bqStudio and EV2400 where they sometimes increment up and sometimes down? Do you perform the same discharge on all tests, and never charge?

    Testing on my EVM I never see it switch between decrement and then increment on the next test.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 140 points

    Hello Wyatt,

    I will try to explain my issue in a different way.

    So, for example (values are not the BQ values but it's the same idea, right ?)

    Step 1 : I take 5 boards (same boards)

    Step 2 : I do the calibration process of TI on 5 boards. Same conditions (battery even, board even, way of current even, consumption even)

    Step 3 : After verification all the value are good and the accumulated capacity counter of each BQ are near from the real current consumption during 5sec. (first message of the thread)

    Some of them are "counting up" and the other are "counting down" but the accumulated capacity are good in both case. WHY some times counting UP and some times DOWN ???

    Step 4 : Make an average of the diffrent values to put it on each BQ for the production phase at the factory. Then they are all counting in the same way (here down).

    Can you tell me why this is happening ? 

    Regards,

    Goulwen LE BOZEC.

  • 0 in reply to Goulwen LE BOZEC
    TI__Guru** 105760 points

    Hello Goulwen,

    I was able to re-create which way the gauge counts by changing the CC offset, I'm guessing this could be your issue. Can you export the .gg file when you get the EV2400 so I can take a look at the configuration? Maybe there is an issue when you write these calibration values, but it can cause this to happen.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 140 points

    Hello Wyatt,

    I was able to re-create which way the gauge counts by changing the CC offset, I'm guessing this could be your issue.

    - Yes that could be the issue i'm facing.. Do you have an explanation about it ?

    Can you export the .gg file when you get the EV2400 so I can take a look at the configuration? Maybe there is an issue when you write these calibration values, but it can cause this to happen.


    - Sorry but we don't have this tool i guess we won't have it one day..

    - I think all my values are nicely write because i'm doing a read verification after..

    Regards,

    Goulwen LE BOZEC.

  • 0 in reply to Goulwen LE BOZEC
    TI__Guru** 105760 points

    Hello Goulwen,

    If your CC offset is written incorrectly it could flip between the two depending on your load current.

    We will need the EV2400 and bqStudio to do further debug because it's not clear if the values are being written correctly.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 140 points

    Hi Wyatt !

    This could be my issue. I think it's this.
    I can not have the EV2400 and make what you'r asking me so...

    Thanks you for your time !

    Regards,

    Goulwen LE BOZEC