BQ27542-G1: 0degC or 5degC low temp charge, charge current is 0.2C,SOC 0% will be held long time for about 3~5h

user4315302

Part Number: BQ27542-G1
Other Parts Discussed in Thread: BQ28Z610-R1

Dear Teams,

We need your helps,the question we have not solve it for a long time.

We find when battery charge at 0degC or 5degC low temperature, SOC 0% will be held long time for about 3~5h。

We have tested 3 project,capacity are 5000mAh,5800mAh and 15000mAh,charge curreng is 0.2C(1000mA,1160mA,3000mA),SOC 0% hold 3h and 5h

But we test another project with bq28z610-r1 gauge IC,capacity is 3850mAh,charge current is 770mA,SOC 0% hold time is less than 1h.

We find it is not chem ID issue,maybe is the gauge IC itself issue.

Atached file are the 3 project test log data,please check.

Thank you.15000mAh system battery 5degC 0.2C charge.log 15000mAh system battery 0degC 0.2C charge -1.log 256009-B 5degC 0.2C charge.log 256010 0degC charge-4.3V -1.log

over 4 years ago

0 Wyatt Keller over 4 years ago

TI__Guru** 105600 points

Hello,

Can you share your .gg file as well? Do you enable the IT algorithm before starting your test? Have all the packs completed a learning cycle?

We can take a look through your .gg file to see your configurations and see if there's something causing this.

Sincerely,

Wyatt Keller

0 user4315302 over 4 years ago in reply to Wyatt Keller

Prodigy 250 points

Hi Wyatt,

Thank you for your reply.

All pack we have done IT enable before start test.

All pack we also finished learning successful.

Attached file is the issue pack GG file,please refer it and check.

Thank you.15000mAh low temp charge long time issue gg.gg.csv

0 Wyatt Keller over 4 years ago in reply to user4315302

TI__Guru** 105600 points

Hello,

If the temperature changes while the battery is near EDV the FCC and RemCap can be recalculated to different levels and may lead to this behavior.

I would check the SMOOTHEN function and SOCHOLDOVRDSG and SOCHOLDOVRCHG bits, by enabling/disabling these two bits it will force SOC to be 0% or 100% if there is an over charge/discharge event.

Sincerely,

Wyatt Keller

0 user4315302 over 4 years ago in reply to Wyatt Keller

Prodigy 250 points

Hi Wyatt,

Now,how to solve this problem for us? or what can we do？

Could you tell us?Thank you.

0 Wyatt Keller over 4 years ago in reply to user4315302

TI__Guru** 105600 points

Hello,

Sorry I referenced the wrong bit names, here is from the TRM:

RMHOLD100 = The fuel gauge will hold StateofCharge() at 100% while in an overcharge condition and not decrement until the charge surplus is equalized. Set to 1 to enable.

RMHOLD0 = The fuel gauge will hold StateofCharge() at 0% while in an overdischarge condition and not decrement until the charge deficit is equalized. Set to 1 to enable.

When the temperature changes when the battery is low or high it could cause an overcharge/discharge condition.

Sincerely,

Wyatt Keller

0 user4315302 over 4 years ago in reply to Wyatt Keller

Prodigy 250 points

Hi Wyatt ,

RMHOLD0 have set to 1 before test. it is charge,so do not trip overdischarge condition

RMHOLD100 have be set to 0 befort test. so it could not from 0% directly to 100%.

it is hold 0% for a long time,but voltage is rising.

0 Wyatt Keller over 4 years ago in reply to user4315302

TI__Guru** 105600 points

Hello,

RMHOLD0 will hold SOC at 0% if the conditions I mentioned occur, try running a test with this bit disabled and it should not hold SOC at 0% when there's a charge.

Sincerely,

Wyatt Keller

0 user4315302 over 4 years ago in reply to Wyatt Keller

Prodigy 250 points

Hi Wyatt,

We have tested with the setting that RMHOLD0 off ,the issue have be closed.

Thank you very much.

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BQ27542-G1: 0degC or 5degC low temp charge, charge current is 0.2C,SOC 0% will be held long time for about 3~5h