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SBD Read Write Utility

Other Parts Discussed in Thread: BQEVSW, BQWIZARD, BQ78PL114

I cannot write command 0x18 (Design Capacity) using the SBD Read Write Utility. I go to that utility and I am able to read, then I try writing a command 0x18 with value 13800 (my pack design capacity) and it doesn;t do anything.

 

What is the proper way to write a command using the SBD Read Write Utility?, any help very appreciated.

 

Thanks

  • I assume you are using bqEVSW for reading and writing data flash. If so, you should be able to navigate to the Data Flash screen, find the parameter you want to change, type in the value, and press Enter.

    There are some things that can prevent data flash writing, however:

    1) If the device is sealed, read/write will not work.

    2) If the device has a permanent failure, write will not work.

    3) If the battery voltage is less than the Flash Update OK Voltage, write will not work.

    Check to see if you have any of those issues and try to correct them if you do.

  • Thanks Chase, I am using bqWizard 3.0.19 and communicating to the EVM board with a bq78pl114 using firmware 4452.

    1) The device is not sealed,

    2) Ok, the device reads voltages, currents, temperatures, is able to update and talk fine via the SMBus, at least for everything except writing an SB command value, whether that parameter is locked or not. I received the board yesterday, and have been extremely gentle to it (wearing ESD strap and following all procedures step by step, for connection ,disconnection etc etc)

    3) Battery voltage is at 26VDC. The recommended ranges are 7.5V up to 50V, correct?

    I am just trying to set the Design Capacity parameter to 13800mAh, which is the capacity of my particular pack. This Design Capacity parameter is used to compute Absolute State of Charge. However, in the SD Static tab panel this parameter is locked, hence cannot be changed, at least from there. But this parameter must be changeable, again, so that it can compute the right absolute SOC....In fact the SB Data interface v1.1 says this parameter is R/W so, why TI locks it in the SBData Static tab?. Also, why when I tell it via the. chem file is a xxxx cell, and via the .tmap file I tell it it has yyy number of cells in parallel, why it can't update this Design Capacity parameter in the first place?, it just puts a 4800mAh value which is incorrect. I told it it was a A123 26650 cell and there were 6 in paralallel. These cells have a 2.3Ah nominal capacity, and 6 in paralell is 13800mAh, so design capacity should e 13800mAh. correct?...

    Thanks again,

     

     

     

  • On a more fundamental question I guess is how do you make sure your absolute and relative SOCs (State of Charge) are correct?. The documentation says how to calibrate voltages, currents, temperatures, but does not say anything about how to make sure the State of Charge computation is right.

    Talking about the same pack (8s6p of 26650 cells). This is a 13.8Ah pack. When I tell the EVM board the right .chem (for A123 26650) and right .tmap (with 6 parallel cells). I can see that the design capacity is 4800mAh, and the remaining capacity is some value totally off of what the pack remaining capacity actually is. Then it computes the absolute SOC as the ratio of remaining cap/ design cap, which is totally wrong for my pack because I start with it fully charged. So how to make sure the SOCs coming from the EVM are correct?.

    I am not saying the EVM board should know this SOCs and parameters from a cold start, maybe not, but at least would be useful to know how to set them to the right values...or a procedure to calibrate those values... maybe I am missing something.

     

    (BTW, my EVM board has had a communication error and now it doesn't turn on again. It was discharging at -7A for like 30min and then failed, and doesn't recover.safety was not inhibit, and current was within limits, so don;t know why it failed)

     

    Thanks

  • Carlos,

    I didn't realize you were referring to the pl114. That is device is supported by a different engineer. You may have better luck getting your post answered quickly by reposting this and adding the part number to your post title.