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Doubts related to bq78pl114 configuration files .tmap and .aux.

Brayts
Prodigy 225 points
Other Parts Discussed in Thread: BQ78PL114

Hello,

I'm using a bq78pl114 and I have some doubts about some configuration files that this IC uses.

In application report SLUA495A (http://focus.ti.com/lit/an/slua495a/slua495a.pdf) says in page 1 that the minimum number os parallel cells that we can put in the .tmap file is 1!.

So, in my application, my battery stack is formed by 4 Li-ion series cell, I don´t whant any cell in parallel configuration. Can I put the number 0 in the indicated line of the .tmap file when I open it with the Notepad??How can I work with this situation?

Another thing that I don´t understand is in application report SLUA505 (http://focus.ti.com/general/docs/lit/getliterature.tsp?literatureNumber=slua505a&fileType=pdf). In page 3, 3.2.2 (Aux file) I follow all the instructions, so I choose the 0101_8S1P.aux (example) and I open it with text editor. But I crash again when I try to calculate my pack capacity (my bateries have 90Ah of nominal capacity), because I don't whant to use bateries in parallel and I don't understand where it come the "x1.2" of the example formula that is given for we calculate the Qmax value.

So here my doubts are: in the example given in SLUA505 (2400 x 3 x 1.2 =8640)
-It's mandatory the capacity in mAh?
-x 3 is the number of parallel cells, right? What can I use in my situation?(none cells in parallel)
-what means the x 1.2?
-There are any mandatory relation between the Qmax and Qrem values?What can you suggest?

Best regards,
Brayts

  • 0
    Intellectual 372 points

    For me the minimum of 1 in parallel is a logical value; 1=1 cell, i.e. single stages, 2=2 cells in parallel, 3=3 in parallel etc. To enter zero would mean zero cells in parallel = no cells at all, then you do not need any BMS ;-)

  • 0 in reply to Per Hassel Sorensen
    Prodigy 225 points

    PerBear I'm still not understand completly...

    To me series of batteries is something like this:

    (and this is what I want)

    the parallel needs a minimum 2 (batteries in this case), so for 1,2,3,4...etc, the assembly is something like this:


    "To enter zero would mean zero cells in parallel = no cells at all"!! And the cells in series?! You can not use???

    Can you or someone else explain better my questions in the first topic?

    Regards,
    Brayts

  • 0 in reply to Brayts
    Prodigy 225 points

    Hi,
       
    I already understood the meaning of "x1.2" in the example formula "(2400 x 3 x 1.2 =8640)" that is given in SLUA505.

    However I still not understand very well, how can I put a configuration only with series of cells? For pack configuration only with series cells (until 8 for the bq78pl114) in the .aux file and in this formula I only need to use the value 1?

    regards,
    Brayts    

  • 0 in reply to Brayts
    TI__Guru 54715 points

    Yes, enter a value of 1 in the aux file and in the formula. The terminology for the device for 4 series cells in parallel for example would be 4 series cells and 1 parallel cells, the pack would commonly be described as 4S1P.  The parallel count for the device is 1 although there is nothing extra in parallel with the 1 cell.  The parallel count number used to configure the device is the total number of cells in that series element, not the number of additional cells.

  • 0
    Prodigy 10 points

    dear Brayts,

    when battery manufacturers describe their battery designs for example as 4s1p or 3p9s they mean the following: 4 cells (4s) are put in series in 1 'parallel' string (1p) or 3 cells in parallel, 9 of these cell packs in series. There is no '0p' configuration.

    best regards

    Bernd