• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 61 subscribers
  • Views 511 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Fuel Gauge: 25.6V 3Ah LiFePO4

dave51497
Prodigy 90 points
Other Parts Discussed in Thread: BQ2060A, BQ20Z65

Hello,
I'm looking for a fuel gauge IC for a LiFePO4, 25.6V, 3Ah (16x18650 cell) battery pack. The pack has its own protection and is enclosed with access to only the charge and discharge cables. I believe that a simple 'thermometer' style LED array would suffice, but I would also be interested in other options such as
ICs with communication. I'm wondering what part numbers anybody could suggest.
Thanks!

  • 0
    TI__Intellectual 1430 points

    Hello Dave,

    Have a look at the bq2060a and bq20z65  each can be used as a columb counter and drive LEDs.

    http://focus.ti.com/docs/prod/folders/print/bq2060a.html

    http://focus.ti.com/docs/prod/folders/print/bq20z65-r1.html

     

     

     

  • 0 in reply to BatteryBorne
    Prodigy 90 points

    I've decided on going with the BQ2060A, and I have a few questions/comments:

    Since I have a 'single cell' should I wire the pack positive to the VCELL4 pin, and leave the others open. Will that affect the reading and learning of the chip? I'm assuming that I should set the voltage divider to be 1.25V at the battery pack's maximum voltage.

    I read that that the FCC register can’t be updated by more than 256mAh lower or 512mAh rise. Since I have a 3Ah battery pack, this is a really small fraction of my pack capacity and I’m concerned that the FCC will never be updated from the initial programmed value. Is there any way around this? What is the best way to get the chip to learn the actual value? Would it be to allow it to go through a full discharge, full charge x2?


    I would also like to know how much current the LED pins can and should sink.

    Also, VCC is regulated through the JFET at 3.3V correct? I ask because of the application diagram with the NPN BJT on the high side rail with VCC at the base. I would imagine that would really limit the voltage, and therefore current, available to the LEDs.