Temperature for battery profiling nPM1300 using fuel gauge

[Tejaswi K K]

Hi, 

We are profiling our custom battery to get the battery model. using the nRF fuel gauge connected to the nPM1300-EK board as we intend to use the nPM1300 nrf_fuel_gauge.h to calculate the battery percentage. The profiling says it takes roughly 48 hours at each temperature and to profile the battery at three temperatures(5C, 25C and 45C). We have set the first temperature settings to 45C, and expect to set the oven temperature to 45C to profile the battery at 45C. But the nPM power up app asks us to make sure the battery is at room temperature(20C to 25C) before charging, is it a mandate or can we just start profiling the battery at 45C by keeping the room temperature to 45C? Since there is a need to run three different temperature profiles, does the app  give a notification or remainder of the time remaining for the present temperature and when the next profile starts as it is difficult to always be near the app and wait and check if the present profile is completed and as to when the oven temperature be changed to the next temperature profile?  I ask this as we tried profiling the battery individually for 25C and it took roughly 38hours to profile the battery and its really difficult to know when one temperature profile will be complete and I only see the Elapsed time notification. And if so, then we would have to restart the profiling from the beginning.

[Tejaswi K K]

Hi Elfving,

It would be great if I could get help regarding this. Along with the above posted question, I also have a couple more questions related to battery profiling. 

1. As far as I understand, the battery needs to be profiled for three different temperatures (5°C, 25°C and 45°C). One option to do so is by adding all the three temperature settings into one settings option and profile the battery which generates a single .inc file. The second option would be to profile the battery individually for the three different temperatures which generates three separate .inc profiles for the three different temperatures. What would be the procedure to combine them all, if we wanted to profile the battery individually and then get a single battery model out of it?

2. I ask the above question as some batteries have different charging capacities at different temperatures (0.1C at 5°Celcius, 0.5C at 25°Celcius and so on which translates to 100mA at 5°C and 200mA at 25°C)  and if we are profiling all three temperatures at the same time, there is only one provision of constant charging current for all the different temperatures provided in the nPM powerUP application, whereas profiling the battery individually at different temperatures would let us set the different charging currents at different temperatures and we would like faster charging and I am not sure if having the same charging current at all the different temperatures would give a good battery model.   

Thanks,

Tejaswi  

[Elfving]

I ask this as we tried profiling the battery individually for 25C and it took roughly 38hours to profile the battery and its really difficult to know when one temperature profile will be complete and I only see the Elapsed time notification. And if so, then we would have to restart the profiling from the beginning.

So we do have a time estimate for this: the time to profile the battery takes approximately 48 hours per temperature. I would just wait for two days for each of the tempratures. Does that help?

I need some more time to answer the two last questions from your previous response.

Regards,

Elfving

[Elfving]

Hi again, hope you've had a good week-end.

1. Yes, you can profile the battery at multiple temperatures (e.g., 5°C, 25°C, and 45°C) either in a single session or separately. When profiling in one continuous sequence across different temperatures, the PowerUP tool will automatically generate a single .inc file that integrates the measurements from all three temperature conditions into a one model.

Each profiling session, regardless of temperature, generates a CSV file that contains the complete battery measurement data, including voltage, current, and temperature readings. This raw data serves as the input for generating the battery model at the specific temperature.

That csv file can be found in the folder that user initially select. 

If you prefer to profile the battery at each temperature individually, then for each session, a distinct CSV file will be created. These CSV files can then be combined within the PowerUP software to generate a combined battery model that covers all three temperature ranges.

The procedure for combining profiles is as follows:

Navigate to the Profiles tab in the nPM PowerUP PC application.
For each CSV file corresponding to the 5°C, 25°C, and 45°C profiles, use the Add Profiles option to import the data for the respective temperatures into that new project.

Once all profiles are imported, click the Process Now button. PowerUP will then analyze the data from the individual profiles and generate a single battery models for each temperature specified.

After processing is complete for all temperatures, you can save the final model, which will include all temperature-specific data, as a single .inc or .json file by selecting the Save option under the Projects tab.

2. The nPM1300 fuel gauge solution does not perform battery characterization during the charging process. Profiling and battery modeling are exclusively carried out during the discharge cycle. While the fuel gauge remains active and functional during both charging and discharging operations, the actual data used for profiling is gathered only from the discharge phase.

Before starting the profiling process, it is essential that the battery is fully charged under standard conditions, which typically involve room temperature and the recommended charge current specified in the battery’s datasheet. This ensures consistency and accuracy when generating the discharge profile for model creation regardless of the battery profiling temperature. 

Regards,

Elfving

[Tejaswi K K]

Hi Elfving,

Hope you had a great weekend as well. 

Thank you for clearing my doubts and sorting out this issue and clarifying all the doubts I had regarding battery profiling. The battery profiling involving all the temperatures in a single session crashed the nRF powerUp app the multiple times once one of the temperatures were done and we had to restart the profiling from the beginning. The battery profiling individually as you have mentioned above at individual temperatures makes it much more easier. Thank you so much for explaining it to me in detail.

Regards,

Tejaswi