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Chemistry evaluation

Bob White
Intellectual 660 points

In trying to select the correct Chem ID, is it correct to adjust my Wizard Charge Control | Design Capacity value, so that I get 100% when charged?  Or maybe change the Wizard Safety Level 1 | CUV Threshold to a higher value to stop the discharge sooner?

I guess my problem is that I don't know how to evaluate the performance of the Gas Gauge function.

Bob

 

  • 0
    TI__Guru 73830 points

    Bob, 

    If you can collect some data for me, then I will try to check your ChemID.

    • You will need to monitor the cell voltage, cell temperature, current and set the time to log every 1 second. You can log additional data, but that it all that I need.
    • Charge the pack to full and allow it to taper to a C/100 taper current. 
    • Let it rest for at least 2 hours, then discharge it at a C/10 rate to discharge complete.
    • Let it rest for an additional 2 hours.

    Please send the log file.

    Regards
    Tom

  • 0 in reply to ThomasCosby
    Intellectual 660 points

    Hi Tom,

    That's great.  I have so far been working with some cells in a 7s1p configuration.  They are the wrong cells, meant for my learning of the Wizard only.  This means that I have to make a new battery for this test, so that the information you provide can be used for my production battery.

    I have two dumb questions:

    1.  Should I use a multi-cell battery on the EVM to collect the log, or can I do it with a single cell (on the bq78PL116EVM)?

    2. How do I go about starting fresh on the EVM for this data collection?  At this point, it expects me to be using my 7-cell battery with .aux file that I created.

    Thanks,

    Bob

     

  • 0 in reply to Bob White
    TI__Guru 73830 points

    Bob,

    You can use the seven series cell configuration to collect the data, but it important that there is only one parallel cell. Just log the cell voltage and cell temperature for at least one of the cells. The current will not be affected by multiple cells since they are in series.

    Tom

  • 0 in reply to ThomasCosby
    Intellectual 660 points

    Hi Tom,

    I finally got the log file for my battery.  I made a three-cell version and used the Wizard to create a csv file of the charge and discharge.  C/10 takes quite a while to log.  There is one hickey in the middle of the C/10 discharge plot, let me know if it ruined the log for your purposes and I can do it again.  The log actually starts at about the 6500 second point, before then I was charging and discharging to set up for the required sequence.  I left the data in in case it is of use.

    The .csv file is attached.  I found the insert file icon above to not do anything, so I used the paste from Word icon instead.

    At least I tried.  Excel doesn't like the 15 MB .csv file, I had to shut it down with Task Manager.  Is there any other way I can send the .csv file to you?  98,903 rows of data is more than I can scroll through to select in Excel.  This was two days of sampling every second.

    Thanks,

    Bob