BQ27520-G4: How to disable/enable gauge learning in the field and how to check updated Qmax & Ra-tables

Hello Daniel,

I have assigned someone to take a look at this and they should respond by end of day tomorrow.

Sincerely,

Wyatt Keller

Hi Daniel,

Can you send over your .gg file so I can observe more parameters to discover why this behavior is happening? As soon as I get that file I'll head into the lab and work on finding a solution.

Thanks, 

I send you 3 .gg files.

One file is a direct export right after a presumably successful learning cycle ("From_LearningCycle")

"Modified_from_LearningCycle" is the same as "From_LearningCycle" but I modified all Ra tables to match Ra0 and Ra0x (the only tables that the learning cycle updated automatically)

"FromGG_maker_tool" is my most resent file that I currently test for accuracy. 

My main question is whether the gauge self-learns once it is in field-use and how I can check that. So far I have not seen any parameters update when the gauge is used with the final product.FromGG_maker_tool.csvModified_from_LearningCycle.csvFrom_LearningCycle.csv

Hi Daniel,

I took a look at your .gg files and nothing here is giving me insight into what is preventing parameters on the gauge from updating. There could be a variety of conditions that disqualify Ra table updates and QMax updates when doing chg/dsg cycles So I will need to take a look deeper to figure this out.

In order to do so, I will need you to send me a .log file of all of the registers on the device over a chg/dsg cycle so I can see what your current/temperature/other parameters are that may be prohibiting the device from updating in the field.

Thanks,

Jackson

Took me a while to record a .log file.

The attached file is recorded from the fuel gauge under field use. Mostly the battery will be charged outside the product so that the fuel gauge won't "see" the charge cycle but only the discharge cycle.dis-charge-dis for TI.log

Daniel,

If I understand correctly, the gauge will not ever see the charge portion of the chg-dsg cycle? This can lead to very inaccurate gauging. The gauge should always be connected to the battery to observe both charging and discharging otherwise many vital parameters will not update over time.

Thanks,

Jackson

Hi Jackson,

yes, most of the time the battery will be charged with a separate charger, hence the gauge is not connected. So in this scenario I will assume the gauge won't learn.

Did you check the .log file? There I charged the battery with the gauge connected. Do all parameters look ok? I could imagine that the battery temperature during the charge cycle is reported too low (~-44C) and therefore the gauge won't learn.

Thanks, Daniel

Hi Daniel,

I have looked at the log file. Do you know why it is reporting -44C? Is this done intentionally for your application? A temperature this low certainly disqualifies any QMax updates and probably is what is affecting the ability to update other parameters as well. Can you re run the test at 25C and see if the behavior continues? I would Imagine that the gauge is trying to update values but since you somehow jump from 27C to -40C in 13 seconds, the gauge is disqualifying these updates.

Thanks,

Jackson