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bq34z110 and Peukert's effect (high discharge current)

IGW84
Prodigy 50 points
Other Parts Discussed in Thread: BQ34Z110

Hi all,

The data sheet for the bq34z110 is not explicit on this issue or I have missed it (in which case sorry).

Does the lead-acid discharge algorithm embedded in the bq34z110 account for Peukert's effect - that is, the fact that, for lead acid especially, there can be a significant reduction in available capacity depending on the discharge rate.  It is usually expressed as an exponential index - Peukert constant.

If so where is the index set or what is the assumed value.

Thanks,
Ian

  • 0
    TI__Guru 73830 points

    Ian,

    The bq34z110 has current and temperature compensation that should compensate for the Peukert's effect.

    Regards
    Tom

  • 0 in reply to ThomasCosby
    Prodigy 50 points

    Hello and thanks Tom.

    I have read the datasheet a number of times now and I can't see where this is described. But I may have missed it.  Can you give me any pointers please?

    (As a side note, for some reason I don't find this particular data sheet as clear as most of the (many) TI ones I have read.  Something about the phrasing and some of the possibly slightly convoluted sentences makes it just a little harder than I normally find.  This may well be in my grey matter, but it may be meaning I am missing something.)

    Thanks,
    Ian

  • 0 in reply to IGW84
    TI__Guru 73830 points

    Ian,

    The datasheet does not address Peukert's effect. The general IT algorithm's should compensate for current and temperature changes in lead acid cells. The IT algorithm has been tweaked for lead acid cells, but it basically works the same as IT on other devices. If you are familiar with our devices, then you already understand how the gauge works. If you are not that familiar with IT, then please review the Applications Book. (search for SLUA404 on the TI website) Please let us know if you find performance issues and we may be able to address them with a parameter change or firmware update.

    Regards
    Tom