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BQ27441-G1: Wrong remaining capacity

Marcel Derleh
Prodigy 20 points
Part Number: BQ27441-G1

So I tried to import some functions from the Sparkfun-Arduino-Lib available for this IC. I am able to read the DeviceID and any register I like, so far so good.

I've set the Design Capacity in SubClass 82 / Offset 10 to 0x005A (90mAh), after a Softreset the value can be read by requesting Register 0x3C which gives me the modified value.

But after reading nominal available (0x08), full available capacity (0x0A), remaining capacity (0x0C) and full capacity (0x0E) I'm getting weird values that don't look anything like my battery stats. A fully loaded battery gives me 20mAh as remaining capacity or 32mAh as full capacity. Does the IC need some loading-cycles to properly function?

  • 0
    TI__Expert 4450 points
    Hello Derleh,

    Have you choose the right chemID and do self-learning cycle for your battery?
    The RM and FCC will update during your cycle. Thanks.

    Best regards,
    Sammi Shang
  • 0 in reply to Sammi Shang
    Prodigy 20 points

    As this is the BQ274-Series I don't think choosing the chemID is possible?

    I'm running some tests with other batteries right now by fully discharging and charging with the right Design Capacity value and 3V terminate voltage. As far as I can see, the batteries don't come close to the specified 90-100mAh whereas other tests seemed to proof the specifications. I've read outside the datasheet that the IC is designed for 200mAh - 8000mAh batteries (again, not mentioned in the datasheet but on the TI website), maybe this is responsible for the wrong values?

    By the way, is there a method to write the configuration into the ROM of the IC? It would be tiresome to reconfigure everything after the voltage cuts from the IC....