NPM1300 battery profiling capacity vs vTerm

[robsrick]

I'm profiling a battery with the following specs

I've just finished the first profile and for a capacity of 500mAh i only got down to about 3.2V and it gave me a warning about not fully discharging which may mean the profile won't be accurate. I guess the capacity is higher than nominal for that particular battery, so it's not covering the full discharge profile.

1) Why doesn't the software just discharge to the cut off voltage and provide a capacity to ensure it covers the full capacity?

2) should i be giving an artificially high capacity to make sure it covers the full range, or is the way i'm doing it okay?

Regards

Robert

[ketiljo]

1) nPM PowerUP should discarge down to the configured cut off voltage, it is hard to say why this didn't happen. Can you please share the files generated by the profile session so we can take a look?

2) No need to set artificially high battery capacity. nPM PowerUP uses this to set correct discharge current during profiling. The battery model generated by the profiling will represent the real battery capacity.

[robsrick]

Hey, the 3 temp profiles have now finished.  I think i misunderstood the warning i was getting in the first instance. it was telling me that the capacity had exceeded the 500mAh i had stated so it took longer than expected to get to the cut off voltage?

I've been testing 4C, 25C and 45C and the final profile, 45C finished last night. Unfortunately i got the following error. I checked it last night and it had gotten to about 476mAh discharged and was all going fine but this morning i saw the following:

when i restart profiling i get the following:

I tried unplugging the battery from the PMIC and re plugging but no luck. Next, i plugged the battery into my custom board which charged it using an NPM1300 successfully for a minute or two. When i plugged it back into my NPM1300EK for profiling it was then detected so i pressed continue to charge the battery again.

I'm going to re-run the 45C profile but i'd like to understand what might have caused this error and how i can prevent it?

Robert

[robsrick]

same thing again upon retry... 

[robsrick]

I've attached the results, could you take a look and tell me what went wrong?  had to stop the test because i needed the laptop for something else but i'm hoping i can just re-run the 45C test and combine the results?

RegardsEEMBLP902030.zip
Robert 

[ketiljo]

The data looks ok. I think the problem is coming from the PCM of the battery. Even though its rated at 2.75V cutoff limit, PCM under voltage protection of the battery has triggered at 3V. That's why it shows an error in the profiling process. But this should not affect the created battery model for fuel gaging. 

Here's the model:

EEMBLP902030_Model.zip

If needed you could also process these data in the PROFILES tab of nPM PowerUP to create the battery model.

[robsrick]

ah great thanks. Glad i don't have to run a week long test again!