BQ27532: FullChargeCapacity(), RemainingCapacity(), etc. are wrong

Hi Alexander,

Could you post the steps you took to program your custom board?

Best Regards,
Ben Lough

Hi Ben,

Thank you for the fast reply.

I have changed certain FMEM parameters on my custom board'd fuel gauge, according to results obtained on TI's evaluation board.
I have acted according to bq27532-G1 Technical Reference Manual (SLUUB04) - Data Flash Parameter Update Example.

And have succeeded. I mean, I read (parameters) from FMEM just the same data I have written.
Among many other, there are proper values of CC Threshold, Design Capacity, Qmax Cell 0 etc.

Now I read registers and see , that
values of NominalAvailableCapacity and FullAvailableCapacity are OK, i.e they based on Design Capacity,
but values of RemainingCapacity and FullChargeCapacity are based on old (default) parameters.
It looks, like something avoids updating.

Additional question - is how may I trust in StateOfCharge? What does it show relation between the former two (right) parameters or last two (wrong) parameters?

Thank you in advance.
Alexander.

Hi Alexander,

Nominal Available Capacity and Full Available Capacity are based on the chemical capacity of the battery and is based on Qmax Cell 0 and Design Capacity. Remaining Capacity and Full Charge Capacity are based on Nominal Available Capacity, Full Available Capacity as well as battery impedance.

Try updating your resistance table.

Best Regards,
Ben Lough

Hi Ben,

Do you mean Ra tables (subclasses 0x5B, 0x5C)?
I'm updating them, as well as most of the other sub-classes in FMEM.
I have performed Learning Cycle on the evaluation board, have written out all values and then have set them to my custom board.
Thus, I have expected to obtain "already learned" fuel gauge on my custom board and avoid learning procedures there.

I suspect ,that I set wrong some value and updates are not "activated".

Thank you.
Alexander.

Hi Alexander,

Yes, the Ra tables. Also how are you sending data to the gauge? Is it with a MCU?

Best Regards,
Ben Lough

Hi Ben,

Yes, I send proper data from my MCU at the Configuration stage of FW (before the main loop).

I have no doubts about most of data (they are taken from the real fuel gauge - on the evaluation board - after learning cycle).

I have no doubts about the way I set these data (I read them just after configuration and I see it the same as I write).

As far as I understand, there should me once more - the last - step (set certain bits), something like "recalculate registers".

The question what are these bits?

Thank you,

Alexander