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How to do chemistry cycle test with EV2400?

Martin Ling
Prodigy 130 points
Other Parts Discussed in Thread: BQ27541-V200, EV2400, BQEVSW

I am trying to complete the configuration process for a design using the BQ27541-V200.

I have the BQ27541EVM, which came with an EV2300 interface. Because this is not supported on 64-bit systems I have instead obtained an EV2400.

After installing the bqEVSW software and the support components that allow it to be used with the EV2400, I am able to communicate with the board and go through the first part of the calibration process.

I now need to do the chemistry selection test, which requires a load circuit to be connected under control of the program and connected to the VOUT pin of the EV2300 HDQ port.

I have built this circuit and confirmed that it works correctly, but the HDQ port of the EV2400 does not output the necessary control signal - the VOUT pin is constant high and is unaffected by the test on/off buttons on page 4C of the bqEASY tool. The EV2400 documentation says that the HDQ port is not supported.

I saw that there are unofficial 64-bit drivers for the EV2300, so installed these and tried to use the EV2300 instead, but they do not work - the EV2300 appears as 'Unidentified Device' in Device Manager, and is not detected by bqEVSW.

How can I complete this test? I see that there is a newer package, GaugeStudio, but it doesn't seem to include the bqEASY tool or equivalent functionality.

  • 0
    TI__Intellectual 2650 points

    Martin,

    you can actually control  your charger and load circuit manually which is what I always do. Using bqeasy to control it really just adds a level of complication.   Just start your gauge  logging every second, charge the battery to full, let it relax 2 hours then turn on your load  and let battery discharge to VTERM  then let it relax 5 hours.

    8473.chemselect_cont.pdf

    Mike

  • 0 in reply to Mike Ewer
    Prodigy 130 points

    Mike,

    That's the process for the learning cycle. I need to first run the chemistry selection test, which I understand includes a more complicated profile including multiple discharge/rest periods and a pulse discharge phase.


    Martin

  • 0 in reply to Martin Ling
    TI__Intellectual 2650 points

    Hi Martin,

    I can understand you feel it has resembalance to the learning cycle for a new gauge but the procedure I attached is the chemistry learning procedure we recommend for the bq20z gauges which comes with the chem ID update zip file. You want the battery fully charged and rested to measure the cell  voltage at full charge and then you discharge  and let it relax so you can capture how the cell voltage responds during discharge and subsequent  relax, ie LIFEPO4 can take a long time to relax for example. Then the mathcad program has best chance to identify the right chemistry. I have not heard of this pulse discharge test you mention as part of chem ID but you may be right for the part you have used. I have forwarded a copy of this post to the relevant team for comment as they may not have spotted it from the title.

    Also see  section 3.2 of  8284.slua372r support of multiple LI-ION chemistries with IT.pdf

    Mike

  • 0 in reply to Mike Ewer
    TI__Genius 10215 points

    Martin,

    The procedure for chem ID selection is actually simpler than the full characterization procedure. We have a Mathcad spreadsheet that can compute the chem ID based on a simple single cycle procedure. The procedure and tool are included in SLUC138 (link below). If you don't have Mathcad, we can get you a match if you send the log file required.

    http://www.ti.com/lit/zip/sluc138\

    For the learning procedure, it is easier to do so manually with a power supply and load (or power resistor). The procedure is below. You will find it is quite similar to the procedure used for finding the chem ID match. At the end of the procedure, Update Status should be 06. It is recommended to use bqEVSW with 1 second logging for any troubleshooting that may be necessary.

    1) Discharge battery to Terminate Voltage at C/5 rate (data flash parameer).

    2) Rest 5 hours.

    3) Send IT enable command (0x0021 to 0x00)

    4) Charge to full at typical CCCV charge rate. Taper must be met (FC bit will set).

    5) Rest for 2 hours.

    6) Discharge to empty at C/5 rate.