RSOC stays at 100% during initial discharge period

Greg Funk

Other Parts Discussed in Thread: BQ40Z50-R1, BQSTUDIO

We have a 1S3P Li-Ion pack using the bq40z50-R1. Pack has gone through a learn cycle and Update Status register is 0x0E so both the QMax and Ra tables have been updated.

During a C/20 discharge the RSOC stays at 100% for the first 2 1/2 hours before moving. At that time the actual capacity is down to about 88%. Is this expected behaviour? Is there any way to adjust?

The chart below shows a constant current discharge at 270mA. The Cap line represents actual capacity as a percentage of the measured capacity during the discharge to 3.1V

Thanks,

Greg

over 7 years ago

0 Benjamin Lough over 7 years ago

TI__Mastermind 26215 points

Hi Greg,

If you have a log file I can take a look at your data. Do you terminate the charge once the FC bit gets set?

Best Regards,
Ben Lough

0 Greg Funk over 7 years ago in reply to Benjamin Lough

Prodigy 45 points

Hi Ben,

Yes, the FC flag was set after charging. I've attached a file with the raw data.

Thanks,

GregDischarge_test_2016_0920.xlsx

0 Benjamin Lough over 7 years ago in reply to Greg Funk

TI__Mastermind 26215 points

Hi Greg,

Could you do a charge/discharge cycle using bqstudio to log your register values? I want to check if charge is accumulating while the battery is resting.

Best Regards,
Ben Lough

0 Greg Funk over 7 years ago in reply to Benjamin Lough

Prodigy 45 points

Hi Ben,

Sorry, I missed your response. I'll run another cycle with bqstudio logging. Should have some data tomorrow.

Greg

0 Greg Funk over 7 years ago in reply to Benjamin Lough

Prodigy 45 points

Hi Ben,

Here is a Discharge/Rest/Charge cycle. It seems better near the end of discharge but still takes about 30min before RSOC moves off of 100%.

Thanks,

Gregsn015_cycle_20160927.zip

0 Benjamin Lough over 7 years ago in reply to Greg Funk

TI__Mastermind 26215 points

Hi Greg,

It looks like your charge was terminated correctly. Which Chem ID are you using? Has it been matched to your pack?

Best Regards,
Ben Lough

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RSOC stays at 100% during initial discharge period