BQ40Z50-R1: BQ40Z50R1-MAX ERROR

Max

Part Number: BQ40Z50-R1

I have designed a 4S1P battery pack with BQ40z50-R1 IC

I have completed the learning cycle for the battery pack and put the battery pack under long run testing ( i.e continuous charging and discharging)

From the testing the battery behaviour is found to be normal.

During the start of the testing the Max Error is 1%,Now the Battery has completed almost 50 cycles the maximum error has now changed to 3%.

Will that affect the battery life cycle?, Why there is change in Max Error ??

Let me know the suggestions

Regards

ANANDAN

over 4 years ago

0 Wyatt Keller over 4 years ago

TI__Guru** 105590 points

Hello Anandan,

The max error indicates the max error expected in the reported SOC. The MaxError gets incremented per battery cycle without a learning cycle being completed. If your pack gets another Qmax and Ra update the MaxError will get reset to 1% again.

Sincerely,

Wyatt Keller

0 Max over 4 years ago in reply to Wyatt Keller

Intellectual 920 points

Hi Wyatt

The Qmax and Ra update will be updated once the batterry has put under rest condition or we need to do the learning cycle again??

Regards

ANANDAN N

0 Wyatt Keller over 4 years ago in reply to Max

TI__Guru** 105590 points

Hello,

It will update if there are 2 rest periods between a 37% change in DOD.

Sincerely,

Wyatt Keller

0 Max over 4 years ago in reply to Wyatt Keller

Intellectual 920 points

Hi Wyatt

You mean that at 37% RSOC on battery at two cycles and putting rest at that time will update Qmax and ra right??

0 Max over 4 years ago in reply to Max

Intellectual 920 points

Hi wyatt,

0 Max over 4 years ago in reply to Max

Intellectual 920 points

Hi wyatt

any reply on this??

0 Jessica H. over 4 years ago in reply to Max

TI__Genius 11535 points

Hi Anandan,

No, it will update if there are two rest periods between a 37% change in the Depth of Discharge, not at 37% RSOC.

Best,

Jessica

0 Max over 4 years ago in reply to Jessica H.

Intellectual 920 points

Thanks

The Battery is still under Long run(Continuous charge and Discharge).Once it is kept in rest position the max error will be reduced ??

Like the same I have put one battery pack under testing and its Max error have not changed from 1% for 250 cycle.

Kindly Guide a way to solve it

0 Wyatt Keller over 4 years ago in reply to Max

TI__Guru** 105590 points

Hello Anandan,

You can check in section 13.13 0x0C MaxError() of the TRM, there's a table of the max error and how it increments.

If your Qmax is updated during those cycles then it will reset MaxError. Al updating the Ra table reduces the MaxError.

Sincerely,

Wyatt Keller

Power management

Power management forum

BQ40Z50-R1: BQ40Z50R1-MAX ERROR