BQ28Z610: BQ28Z610 hold 0%and 100% for long time

Hello Star,

It is very difficult to say without the log file. Would you please attach your log file?

Regards,
Jose Couso

Hi Jose Couso

Atttached log file.

2022-10-15.log

Thanks

Star

Hello Star,

The RSOC starts dropping right when the discharge starts. I do not see an RSOC hold at 100%. Please see below



As for the RSOC at 0%. There's more than 5C change in temperature. The gauge uses FCC and RM to estimate SOC. SOC = RM / FCC. What's probably happening here is that the gauge is underestimating State of Charge due to changes in temperature. 

Please see below how FCC drops. Full Charge Capacity is the total amount of charge that the battery can deliver to a system for a specific set of conditions (average load, temperature).



I would change load select, please read this app note as it will help pick the right load select for best load prediction. Please see Load prediction chapter.

https://www.ti.com/lit/an/slua948/slua948.pdf?ts=1666033643455&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FBQ27426

Regards,
Jose Couso

Hi Jose

Thanks for your help.

The customer relearning and control the temperature within 5C, still have the RSOC jump issue.

2022-10-19.log

Please help check the data.

Thanks

Star

Hello Star,

I will look at it and get back to you.

Regards,
Jose

Hello Star,
 
I was able to get a better performance on the SOC prediction by reducing the Term Voltage, and changing load mode/select to 00

before:
- load mode/select = 07
- Term Voltage = 3100 mV

after:
- load mode/select = 00
- Term Voltage = 2900 mV
- optional, customer can increase Term Voltage Delta to 600 mV to compensate since EDV = Term Voltage + Term Voltage Delta

 

Regards,
Jose