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bq34z100 Charge Termination DF Parameters

Fernando D. Gonzalez
Intellectual 365 points
Other Parts Discussed in Thread: BQEVSW, BQ34Z100, BQ34Z110, BQSTUDIO, BQ34Z100-G1

Hello,

I am performing the learning cycle on a 110Ah, 12V, AGM battery and have a few questions:

1. Recommended charge rate is C/2. My charger maxes out at 15A (between C/5 and C/10). Besides taking a long time, will this be a problem?

2. Taper current is recommended to be between C/20 and C/10. In may case this would be ~7A. In the Taper Current field in DF, should this be entered as 7000[mA] or as 700[cA]? I have X10 set high. 

3. What is an appropriate Min Taper Capacity? I have the Current Taper Window set to 40s.  

4. Appropriate setting for Cell Taper Voltage? 

Thanks for the help.

Fernando

  • 0
    TI__Guru 73830 points

    Fernando,

    1) You can charge at a lower rate.

    2) The X10 bit does not do anything and it is just a reminder to the user that the current and capacity has been scaled. You will need to set the Taper Current to 7000mA.

    3) You can leave the Taper Voltage at the default value. This criteria should be met, before the Taper Current is reached.


    Tom

  • 0 in reply to ThomasCosby
    Intellectual 365 points

    Hi Thomas,

    Thanks for the response. 

    Regarding the Taper Current, bqEVSW sets an upper limit at 1000mA. How am I supposed to overcome this? I thought the trick would be to utilize X10 mode and therefore the Taper Current dimension would be cA but as you told me previously, this is not how it works. Trying to write 7000mA (per your suggestion) does not work (see attached screenshot).

    Over the weekend we ran a learning cycle with a the default Taper Current (100mA). The log is attached. Of course this taper current took a very long time to become reality. However, when this current was finally less than 100mA, the FC flag was not set which would indicate the next Update Status. In fact, our Update Status always read xx04. 

    Another issue we've been having is with regards to the Nominal Available Capacity. In DF, I have Design Energy Scale (DES) set to 10. Also in DF, my Design Cell Capacity is set to 1833mAh. I believe having DES=10 should actually make the IC read this capacity as 1833cAh=18.33Ah. My battery is 6s and therefore the nominal available capacity should be 18.33*6=~110Ah. Why is Nominal Available Capacity in DR not reading a value near 110Ah (see attached screenshot)?

    We would really appreciate a live chat either via Skype/some other program or via telephone. Please let me know if this is a possibility. Thanks! 

    Fernando

    0005_learncycle_05.22.15.zip

  • 0 in reply to Fernando D. Gonzalez
    TI__Guru 73830 points
    Fernando,
    The bqEVSW program restricts the Taper Current to 1000mA, but you can export a gg file and change the Taper Current to 7000mA. You can then import it back into the device and press the Write All button to save it in the DF.

    The Design Energy Scale changes the units from mWh to cWh. It does not affect mAh. They cannot be changed to cAh. You have to scale the current and capacity to support higher capacity packs.

    Qmax and and Ra table only update after discharge on PbA cells. Qmax will not update during the rest period after charge. Your log file also shows that the battery did not rest long enough. You need to let it rest until the OCVTAKEN flag sets.
    Tom
  • 0 in reply to ThomasCosby
    Intellectual 365 points

    Tom,

    I exported the .gg file, opened it in Notepad and edited the Taper Current to 7000mA. I was able to import this in bqEVSW but when I clicked "Write All", the Taper Current field turned red and reverted back to its previous value of 1000mA. See the attached screenshots. 

    Fernando

  • 0 in reply to Fernando D. Gonzalez
    TI__Guru 73830 points

    Fernando,

    I just retested it and verified that I could update the Taper Current to 7000mA using that procedure. I did find that it will not update, if Scanning is enabled or if IT is enabled.

    Tom

  • 0 in reply to ThomasCosby
    Intellectual 365 points

    Tom,

    I disabled scanning but could still not update the Taper Current. I know IT is still enabled so this is likely the problem. Since there is no IT_DISABLE command, I read that I just have to reset, is this correct? I tried doing this via the I2C command (see attached screenshot) but when I click "Write Data", nothing happens and the DF remains unchanged. Is there a better way of disabling IT?

    Fernando

  • 0 in reply to Fernando D. Gonzalez
    TI__Guru 73830 points
    You cannot disable IT on the bq34z100. You can save a gg file and set the Update Status to 00. Then program the device with the default senc file, reload the ChemID and reload the gg file that you modified. This will disable IT.
  • 0 in reply to ThomasCosby
    Intellectual 365 points
    Sorry, I actually have the bq34z110 but I'm sure that doesn't make a difference, correct?

    Where do I obtain the default .senc file? I read that this type of file is factory-set and should remain unchanged. Therefore, isn't it already flashed onto the IC?

    Fernando
  • 0 in reply to Fernando D. Gonzalez
    TI__Guru 73830 points

    The default senc file is flashed onto to device when you receive it, but you have changed the data flash parameters. Here is the default senc file and I have updated a few hidden parameters to make it easier to pass the optimization cycle. Also, I recommend that you switchover to the bq34z100-G1, since you are not far along in the project. It also supports PbA cells and it has some IT improvements and new features. You can download the srec file and bqStudio from the bq34z100-G1 website and flash the program into your devices.

    bq34z110_V0_04_modified2.senc

  • 0 in reply to ThomasCosby
    Intellectual 365 points
    Tom,

    I set the IC to ROM Mode (which a prompt said was successful), and then flashed the .senc file that you attached which also seemed successful. I then put it back in Normal Mode by clicking "Execute" although no prompt was provided. I then tried to flash the .gg file a Taper Current=7000 and Update Status=00. However, the fields both turned red indicating this was no possible.

    Is there an easy way of checking what mode (ROM or Normal) I'm in via a flag?

    I tried requesting a bq34z100-G1 sample but was told that I cannot due to my account type. I'll try ordering one in a few days. Thanks for the recommendation.

    Fernando
  • 0 in reply to Fernando D. Gonzalez
    Intellectual 365 points
    Also, I forgot to mention, since flashing the .senc file you gave me, bqEVSW has had issues auto-detecting my IC and I can therefore not R/W anything.

    Fernando
  • 0 in reply to Fernando D. Gonzalez
    TI__Guru 73830 points
    Fernando,
    Just to confirm, the senc file that I provided can only be loaded into a bq34z110 device. It will not work in a bq34z100 device. You can determine whether the device is in ROM mode by reading a command. It will read a command from I2C address AA when in normal mode and from I2C address 16 when in ROM mode. It will NACK otherwise.

    You can program the bq34z100-G1 srec file into the device that you are currently using. It can be programmed into a z100 or z110 device.

    Tom
  • 0 in reply to ThomasCosby
    Intellectual 365 points

    Tom,

    Yes I realize this. I meant to say that I have the bq34z110, NOT the bq34z100 as I incorrectly posted as the title of this discussion. 

    We will explore the G1's capabilities once we have them but in the meantime we have 5 boards with the 110 on them. 

    I will try your suggestion and get back to you if I still can't reset the update status counter as well as the taper current. Are you available for a telephone conference or live chat? Thanks.

    Fernando

  • 0 in reply to Fernando D. Gonzalez
    TI__Guru 73830 points

    I can support a call next week.

  • 0 in reply to ThomasCosby
    Intellectual 365 points

    That would be great. Please message me a day/time that works best for you. The only day that doesn't work for me is Monday, the 1st.

    In the meantime, could you please supply me with a ChemID (log attached)? This is also a 12V, AGM VRLA battery however the capacity is greater (198Ah at C/20). The last one you ID'ed for me had a 110Ah nominal capacity.  I believe 806 will again be the best match but I just want to confirm. Thank you!

    Fernando

    0001_chemid200Ah_05.26.15.log

  • 0 in reply to Fernando D. Gonzalez
    TI__Guru 73830 points
    Fernando,
    Tuesday or Thursday will be the best days for a call for me. I will contact you offline for the details.

    The Mathcad program shows that ChemID 806 should still be an acceptable match for your cell.

    Tom