BQ34Z100-G1: Average Power register issue

Charles-Elie Demarty

Intellectual 695 points

Part Number: BQ34Z100-G1

Tool/software:

Hi,

I come back about this previous topic.

Here a log with BQ Studio : 8A - 7A - rest 30s.xlsx

Here the corresponding Data Flash : 8814.DF post LC amended.gg.csv

The "Number of series cell" is ok (7) ; the "Voltage Divider" = 61921. And we are with R1 ; so without scale function.

As you can see, the "Average Power" is not compliant also. However, I could observe that the ratio between "Average Power" and calculated (real) power is around 430 (always).

In any case, I don't understand the link with "Voltage Divider" and "Average Power" if we have a good voltage measured.

17 days ago

0 Diego 17 days ago

TI__Genius 14475 points

Hi,

Thanks for the files!

The voltage divider parameter is used to calibrate the voltage. 61921 would indicate a 61921mV : 1000mV ratio. I would verify that your voltage and current readings are correct, and that you have properly configured the physical voltage divider on your board.

Also verify that you are using the external voltage divider, according to the .gg you shared the voltsel is 0

bq34z100-G1 High Cell Count and High Capacity Applications

Regards,

Diego

0 Charles-Elie Demarty 16 days ago in reply to Diego

Intellectual 695 points

Hi Diego,

In the .gg: "Pack Configuration" register = "09e0". So, we have chosen the external divider (voltsel is 1).

About the external divider, we have 1000 KΩ in the top leg and 16.5 KΩ in the bottom leg.

For us, it's compliant because the maximum value on the ADC < 0.9V.

Nbr Cell	RP1 (kΩ)	Vbatt min	Vbatt max	Att	Gain	Value min	Value max
7	1000	16.1	29.89	0.016	61.606	0.261	0.485

Finally, all our batteries are calibrated. The voltage and current accuracy is less than 1%.

0 Diego 16 days ago in reply to Charles-Elie Demarty

TI__Genius 14475 points

Hi,

Ok that's good then, when I opened the .gg it only showed 09.

Good to hear the voltage and current reading are accurate.

Is the 29.89V, the max voltage for the Pack or a single cell?

Regards,

Diego

0 Charles-Elie Demarty 16 days ago in reply to Diego

Intellectual 695 points

Hi,
29.89V it's for the pack (4.27V/cell).

Regards,

0 Diego 15 days ago in reply to Charles-Elie Demarty

TI__Genius 14475 points

Hi,

Thanks for the clarification.

528K ohm resistor should be used for the top leg.

Voltage divider should be set to 33000.

Regards,

Diego

0 Charles-Elie Demarty 11 days ago in reply to Diego

Intellectual 695 points

Hi,

I try to remplace the resistor this week to perform the test.
However, It is not written in the TI document that the Voltage Divider must not exceed a value to have a correct power calculation.

0 Diego 11 days ago in reply to Charles-Elie Demarty

TI__Genius 14475 points

Hi,

They physical voltage diver and the voltage divider parameter both need to be configured properly for the gauge to accurately report voltage and calculate power. There may be an additional issue causing average power to be skewed but we should start with the voltage divider if it is not set up correctly.

Regards,

Diego

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BQ34Z100-G1: Average Power register issue