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BQ35100: Setting up SOH mode without EOS function

Edward Lo
Prodigy 95 points
Part Number: BQ35100

I am trying to use the SOH function of the Gauge to monitor a MnO2 battery and I don't need the EOS function. There is a corresponding Chemistry ID for the battery I am using and I was successfully program it to the gauge.

I want to test out the SOH responds using a power supply and corresponding dummy resistor to simulate battery thermostat.

We are using 8 battery in series for 24V. But as soon as I setup the gauge to SOH mode and trigger the GE line, the SOH drop by the Max SOH Delta on each trigger till 0%.

Using BQ Studio, The values in "Data Memory" -> "Gas Gauging" such as

"Cell Design Capacity mAh", "Cell Design Voltage", "Cell Terminate Voltage", and "Max Load" are not automatically set when the Battery chemistry was programmed so I changed those to the proper value along with the "Series Cell Count" to 8.

Cell Design Capacity mAh : 1300 (mAh)
Cell Design Voltage : 3000 (mV)
Cell Terminate Voltage : 2000 (mV) <- Our circuit can't go below 16V, the actual is around 1V, but we set this to 2V
Series Cell Count : 8 (Counts)
Max Load : 500 (mA)
State of Health : 100 (%)
State of Health Max Delta : 1 (%)


However, the changes doesn't help with the SOH issue. I also try to play with other setting but I am getting this message when I try to use the "New Battery" command.

WriteMACReadBlock communication error :First two bytes of MAC response read from device does not match MAC command sent.

1. Do I need to setup the EOS in order to use the SOH function?

2. Are we messing up the SOH with the wrong terminate voltage? If this is the case, how can I look up the actual value since the spec didn't specified it?

Thanks

Ed

  • 0
    TI__Guru** 105760 points

    Hello Ed,

    Can you share your .gg file here so we can take a look at your configurations?

    Is the chemistry ID an exact match with the cell you're using? The gauge should be in SOH mode for that battery chemistry type.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 95 points

    Looks like I have trouble uploading the .gg file so I include it as txt at the end of the post

    When I run the test, I am only using a power supply and 10kohm resistor to simulate the battery at room temperature.  So I am not using a battery during the initial test to flush out the Gauge setup.

    I tried using a different chemistry ID (0605) with similar property but got the same issue.  The .gg file is using the 0605 chemistry ID but otherwise the rest of the register setup are identical.  

    * Texas Instruments Data Flash Binary Image File.

    * All values are hexadecimal and begin at Data Flash Offset zero.
    *
    * File created on Wed Jan 20 18:27:29 2021
    * Device Name bq35100
    * Device Identifier bq35100 v1.02 build 9
    * Off-
    * set +0 +1 +2 +3 +4 +5 +6 +7
    0000: 7C 43 61 13 90 5D C6 73
    0008: FA 88 00 4C 00 00 FB 00
    0010: FB 00 00 00 00 00 CF DC
    0018: 17 F3 00 00 17 F3 51 F6
    0020: C9 F4 14 52 09 21 32 6D
    0028: 00 00 3A 36 FD 91 00 25
    0030: 30 01 00 EF 10 20 00 00
    0038: 00 00 00 00 00 00 00 00
    0040: 00 00 00 00 00 00 00 00
    0048: 00 00 00 00 00 00 00 00
    0050: 00 00 00 00 00 00 50 7C
    0058: 00 00 00 00 4C 0B 3D 70
    0060: 07 62 71 33 35 31 30 30
    0068: FF FF 00 00 00 00 00 00
    0070: 00 00 00 00 00 06 05 0C
    0078: B9 0C 39 0B B9 0B 78 0B
    0080: 59 0B 55 0B 43 0B 3A 0B
    0088: 4E 0B 26 0B 2C 0B 38 0B
    0090: 10 0B 10 0B 0F 0B 15 0A
    0098: F7 0A F2 0A E6 0A E4 0A
    00A0: EA 0A DA 0A C2 0A C0 0A
    00A8: BE 0A B6 0A A1 0A AB 0A
    00B0: 84 0A 70 0A 56 0A 52 0A
    00B8: 21 0A 1C 0A 18 09 B7 09
    00C0: 60 09 E6 08 A1 07 9B 0C
    00C8: 33 0A C6 23 A3 EB 73 26
    00D0: 20 38 C9 37 46 38 F3 37
    00D8: 7A 34 D5 36 5B 3A 17 34
    00E0: 32 2F 14 36 08 35 66 38
    00E8: 65 38 F4 36 0C 35 0F 38
    00F0: B3 38 57 37 A8 38 C7 3A
    00F8: D5 3A 6E 3A EF 3C 3F 3D
    0100: 64 34 66 43 0A 45 0E 4E
    0108: 49 4D 2D 54 C7 55 A3 61
    0110: B7 5D 2C 60 FE FF 6B 1B
    0118: 3D EC 09 FF F6 00 08 00
    0120: 09 00 12 00 2E 00 32 00
    0128: 30 00 2F 00 30 00 3A FF
    0130: DE 00 1D 00 59 00 62 00
    0138: A0 FF E4 FF DC FF F0 FF
    0140: DE FF AF FF A9 FF 7B FF
    0148: 4E FF 2C FE F3 FF 2F FE
    0150: D0 FF 0B FE 36 FF 01 00
    0158: 00 00 00 00 00 00 00 00
    0160: 00 00 00 00 00 00 00 00
    0168: 00 00 00 00 00 00 00 00
    0170: 00 00 00 00 00 02 B2 02
    0178: 0F 01 E6 01 AF 01 84 01
    0180: 79 01 88 01 A3 01 A6 01
    0188: 99 02 59 02 22 02 3B 02
    0190: 5F 0A 7A 00 43 00 47 00
    0198: 53 00 6E 00 60 00 4D 00
    01A0: 60 00 56 00 54 00 52 00
    01A8: 51 00 5C 00 67 00 7B 02
    01B0: 92 C1 F3 09 00 14 0A F0
    01B8: 00 32 01 C2 01 23 45 67
    01C0: 89 AB CD EF FE DC BA 98
    01C8: 76 54 32 10 04 14 36 72
    01D0: FF FF FF FF 0B A6 02 58
    01D8: 02 02 26 0A 8C 02 0B B8
    01E0: 00 32 02 00 64 00 05 00
    01E8: 00 0A 00 00 7F FF 0A F8
    01F0: 30 00 00 19 00 00 00 14
    01F8: 01 00 00 00 14 01 06 40
    0200: 18 C0 0C D0 07 D0 08 0B
    0208: B8 00 01 64 FF FF FF FF
    0210: FF FF FF FF FF FF FF FF
    0218: FF FF FF FF FF FF FF FF
    0220: FF FF FF FF FF FF FF FF
    0228: FF FF FF FF FF FF FF FF
    0230: FF FF FF FF FF FF FF FF
    0238: FF FF FF FF FF FF FF FF
    0240: 00 00 7F FF F8 30 00 00
    0248: 00 00 00 14 00 00 00 14
    0250: 00 00 1F 00 00 00 0F FF
    0258: FF 02 FF FB FD 14 00 78
    0260: 00 00 00 00 00 00 00 00
    0268: 00 00 FF 19 A0 80 0A 07
    0270: FF FF FF FF FF FF FF FF
    0278: FF FF FF FF FF FF FF FF
    0280: FF 00 FF FF FF FF 7F FF
    0288: 00 00 00 00 7F FF 09 08
    0290: 2D FC 7F FF 10 90 26 AC
    0298: FF FF FF FF FF FF FF FF
    02A0: FF FF FF FF FF FF FF FF
    02A8: FF FF FF FF FF FF FF FF
    02B0: FF FF FF FF FF FF FF FF
    02B8: FF FF FF FF 00 00 00 00
    02C0: 55 FF FF FF FF FF FF FF
    02C8: FF FF FF FF FF FF FF FF
    02D0: FF FF FF FF FF FF FF FF
    02D8: FF FF FF FF FF FF FF FF
    02E0: FF FF FF FF FF FF FF FF
    02E8: FF FF FF FF FF FF FF FF
    02F0: FF FF FF FF FF FF FF FF
    02F8: FF FF FF FF 00 00 00 00

  • 0 in reply to Edward Lo
    TI__Guru** 105760 points

    Hello Edward,

    I can't easily use this information to see your settings. .gg files are readable in .csv format.

    If you have an exact battery match I would test with the actual battery, most of the time when these systems are tested without the battery we see this kind of behavior. Is your power supply set at the exact voltage the relaxed battery at full charge is?

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 95 points

    BQ_SOH_Test - Copy.csv

    Hi Wyatt

    I attached the file as .csv but doesn't look like it will upload.  Can I email it to you directly?

    With 8 cell in series (slight variation in each cell) and diode drop from the reverse protection, the full stack even at brand new won't match the expect relaxed battery at full charge.

    Ed

  • 0 in reply to Edward Lo
    TI__Guru** 105760 points

    Hello Ed,

    If the voltages don't match what's saved in the chemID it will not be able to gauge very well, the gauge uses the voltage as a reference for the SOH and if there's a lot of voltage drop it will keep dropping SOH.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 95 points

    Hi Wyatt

    With the profile I sent you, I can set the power supply voltage to 24V with the expecting 8 cell in series full charge at 24V,  I get 99% when I send "new battery" command, it is off by the max delta that I set. SOH will be 90% if I set the max delta at 10%.

    Without changing the power supply voltage, the SOH value will keep decreasing every time I toggle the GE line till the SOH read 0%

    Ed

  • 0 in reply to Edward Lo
    TI__Guru** 105760 points

    Hello Ed,

    I'd like to review your .gg file before further debug so we can see all your settings to make sure they're correct. It should settle at some SOH if the gauge is configured correctly.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 95 points

    Hi Wyatt

    Did the .csv i uploaded sufficient or you want me try upload the .gg file again?

    Ed

  • 0 in reply to Edward Lo
    TI__Guru** 105760 points

    Hello Ed,

    This is not the .gg file, if you go to data memory and click export you will get the .gg file.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 95 points

    BQ_SOH_Test.zip

    I have to change the extension from .gg to .csv otherwise the firewall from my end blocks it.  I will try zipping it and see.

  • 0 in reply to Edward Lo
    TI__Guru** 105760 points

    Hello Ed,

    This is still not the .gg file, I attached an example .gg file from my gauge with the default values.

    bq35100_example_gg.gg.zip

    Sincerely,

    Wyatt Keller

  • 0 in reply to Edward Lo
    Prodigy 95 points

    BQ_SOH_Test.csv

    Hi Wyatt 

    Sorry, though you were looking for the Hex dump.  Please see the attached file.

    Ed

  • 0 in reply to Edward Lo
    TI__Guru** 105760 points

    Hello Ed,

    Thanks, I will look through your info and provide some feedback by the end of the week.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    TI__Guru** 105760 points

    Hello Edward,

    I was able to do some testing with your configuration and chem ID and see the SOH decrements down to the value expected from the chem ID.

    I took a look at your config, your VIN gain is much higher than the default, did you perform a calibration on the gauge?

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 95 points

    Hi Wyatt

    We are using the gauge for ~27V max so we have to change the VIN divider value and that's the Gain we get from calibration. 

    Any reason you can think of that could cause our SOH number to behave like the way we did?  We see the same behavior on the evaluation board (with the VIN divider value changed) and on a PWB that we design (with the same VIN divider value)

    Can we damaged the gauge if we put over 1V at VIN?  Where the Voltage and Temp mon function would still work but SOH doesn't?

    Ed

  • 0 in reply to Edward Lo
    TI__Guru** 105760 points

    Hello Ed,

    As long as the calibration was done correctly it should not be always decreasing by SOH max delta.

    The pin won't be damaged unless it passes the absolute max, it becomes non-linear after 1V. What voltage is reported by the gauge after calibration?

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 95 points

    The Voltage and Temp would report the correct value.  Only the SOH won't work properly.

    Can you give me a detail step in BQ studio after Cal like reset, gauge_start, etc and I will repeat and see if I missed anything when I run it.

  • 0 in reply to Edward Lo
    TI__Guru** 105760 points

    Hello Edward,

    If you are reading the correct voltage, it should be correlate to the correct SOH.

    Try setting the cell term voltage to 900mV.

    e2e.ti.com/.../840232

    Sincerely,

    Wyatt Keller