BQ27426: About manual modification of Qmax Value

hello，

Thanks for you reply。

Background:

Battery design capacity 1230mAh, reserve capacity 350mAh, voltage flat area 3679-3803mV.

1, The Qmax value cannot be modified by Qmax Cell 0. Is there any other way, to modify the Qmax value?

2、Is there a way to make Fuelgauge learn the Qmax and Ra of a 55% aging battery?How does it work?

背景：

电池设计容量1230mAh，储备容量350mAh，电压平坦区3679-3803mV。

1、Qmax值不能通过Qmax Cell 0修改，是否有其他办法，可以修改Qmax的值？

2、是否有办法使Fuelgauge学习到老化程度55%电池的Qmax和Ra？如何操作？

hello，

1、What is the specific reason for not being able to modify?

2、What are the effects of manually modifying the Qmax value?

Adrian said:

1. Qmax is only updated when the gauge is being used. So completing charge and discharge cycles. Also, completing the learning cycle will update qmax.

3、Performing a self-learning process (passedcharge>Qmax*37%), what is the maximum allowable battery aging in %?

Adrian said:

2. There is not a way to do this. The gauge will just calculate the Qmax and Ra when the time comes for the battery.

1、不能修改的具体原因是什么？

2、手动修改Qmax值会有哪些影响？

3、执行自学习过程(passedcharge>Qmax*37%)，最大允许的电池老化程度是多少%？

Hello Wang,

1. This is one of the most important values that is used by our firmware for accurate gauging and should be only calculated from the firmware and not user inputted.

2. The effect would be inaccurate SOC readings.

3. I am not sure what you mean by this question, can you please clarify?

Regards,

Nick Richards

hello Nick，

Battery design capacity 1230mAh, reserve capacity 350mAh, voltage flat area 3679-3803mV.

1, the device follows a 1-month cycle to self-learn the battery, when the battery ages to SOH=? %, Fuelgauge will not be able to learn successfully again?

2、Is there any limitation on the battery aging level when FuelgaugeIC is self-learning?

Adrian said:

3. I am not sure what you mean by this question, can you please clarify?

电池设计容量1230mAh，储备容量350mAh，电压平坦区3679-3803mV。

1、设备按照1个月周期对电池进行自学习，当电池老化到SOH=？%时，Fuelgauge将不能再学习成功？

2、FuelgaugeIC在自学习时，对电池老化程度有没有限制？

Hello Wang,

1. The fuel gauge will be able to learn throughout the entire battery's lifespan.

2. There is not a limitation on battery aging level for self-learning.

Regards,

Nick Richards

hello nick,

The fuelgauge self-learns that Qmax updates need to meet Qmax*37%. How does self-learning work if the battery ages to the point where the capacity is less than Qmax*37%?

Adrian said:

1. The fuel gauge will be able to learn throughout the entire battery's lifespan.

fuelgauge自学习，使Qmax更新，需要满足Qmax*37%，如果电池老化到容量不足Qmax*37%时，如何进行自学习？

Hello Wang,

Qmax will decrease as the battery ages.

Regards,

Nick Richards 

Hello,

1. FuelgaugeIC does not place a limit on the degree of battery aging during self-learning. However, when the battery ages to less than Qmax*37% capacity, it will cause Qmax not to be updated. Is this understanding correct?

2.The requirement for Passedcharge for Qmax update after battery aging. Is there any other requirement other than greater than Qmax*37%? E.g. Passedcharge>Design capacity*37%?

1、FuelgaugeIC在自学习时，没有对电池老化程度做限制。但当电池老化到容量不足Qmax*37%时，将导致Qmax不能更新。这个理解是否正确？

2、除了电池老化后，Qmax更新对Passedcharge的要求，除了大于Qmax*37%以外，还有其它要求吗？如：passedcharge>Design capacity*37%?

Hi Nick，

Qmax will gradually decrease, and Fuelgauge will no longer be able to self-learn when the battery charging\discharging power cannot satisfy passedcharge>Qmax*37%. Is this understanding correct?

Adrian said:

1. Qmax is a value that is always updating. As the battery ages, the Qmax value will decrease accordingly. 

是不是可以理解为：Qmax会逐步减少，当电池充\放电电量无法满足passedcharge>Qmax*37%时，Fuelgauge将不能再进行自学习？

Hello Wang,

Your understanding is correct.

Regards,

Nick Richards