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Dear TI team,
Together with my team I been working on a device that integrate some of components from your portfolio. We designed consumer device that has backup battery support and for such purpose we decide to use BQ24725A as a charger and BQ28z610 as a battery protection and gauge. Our battery configuration is 2s1p and we are using 18650 Li-Ion cells inside pack. During the tests we have faced some inconsistencies with the estimation and figure it out that probably this is coming from the wrong chemical ID. Our hardware design is based on TI reference manual and the connection between charger and a gauge is almost identical to the PMP40496 Reference design.
We have found all the information how to log the data using BQstudio and how to get the ChemID based on these data from the TI. Our plan is to run the relax-dischg-relax in order to get logged data that are required by TI. Before we do this there are some concerns, we have and it would be very useful if you can provide some information so we can proceed with the process. Our concerns are following:
I will really appreciate if you can provide answers on my questions because we are planning to rollout first batch of devices to end customers soon and this cannot be done before we finish complete battery commissioning and setup.
Thanks in advance.
HI Miroslav,
Hi Nick,
thank you very much for the fast response to our questions.
I have a couple of more concerns so I will be thankful if you can give me just a bit more information about questions numbers 1 and 4.
1. You said we need to do complete LC and after that, we will have a golden image, but before that, we need to find a chemical ID flash it inside the gauge before LC is started. Based on your answer, it seems like we need to do a complete learning cycle and log data during relax-discharge-relax to get the logs that should be uploaded to TI for obtaining a matched battery chemical ID, is this proper understanding of your answer?
4. Yes this is fine, we know that CC/CV is the usual procedure, but we are facing that in our application charger never switch from CC to CV. We would like to detect the end of charge by measuring the voltage on BQ24725A_Iout and terminate the charging once the measured voltage is proportional to 18mA charging current. We set the charging voltage to 8.4V which is the same as the OVP on the gauge and the gauge terminate charging before the CV is activated. Do we need to set the BQ24725A charge voltage to 8.35V in order to reach CV mode and be able to measure 18mA taper current and terminate charging?
Our procedure is the following:
Are these steps are ok?
Thanks in advance.
1. Yes, it is the GPCCHEM tool.
4. As far as I know the charging voltage for smart chargers are configurable. You will set it to the max charging voltage for CV to begin.
Yes the procedure looks correct, please add logging IVT and dump gg file prior to start of cycle.
Kang,
thank you very much for the feedback you provided. This solved my doubts.
Best regards.