BQ27426: State of Health function enable

George Yang2

Prodigy 220 points

Part Number: BQ27426

Any register or something need to be set to enable SOH?

We already do the 3 cycling for charge(0% to 100%) -discharge(100% to 0%), but 0x21 is still 0x00.

Thanks.

over 4 years ago

0 Steven Yao over 4 years ago

TI__Genius 12215 points

Hi, George

The code for SOH Status has been removed due to code space constraints, however, the SOH is still valid to use

0 George Yang2 over 4 years ago in reply to Steven Yao

Prodigy 220 points

Hi Steven

Confuse me, the code removed but SOH function still workable?

As I know, the SOH (0x21) would be changed 0x00 > 0x01 ...>0x03 after few cycling of discharge-charge.

However, the 0x21 always is 0x00...

Or, 0x21(SOH status) is removed but we can check SOH only by 0x20(SOH percentage)?

Thanks.

0 Onyx Ahiakwo over 4 years ago in reply to George Yang2

TI__Guru* 76230 points

Hi George,

I am confused what the issue is? Are you trying to do a learning cycle? What you should be looking out for is the qmax_up and res_up flags getting set.

That is really what matters.

thanks

Onyx

0 George Yang2 over 4 years ago in reply to Onyx Ahiakwo

Prodigy 220 points

Hi Onyx

Thanks. I will check QMAX_UP & RES_UP also.

However, the 0x21 and 0x20 can be an indicator for SOH?

My question is SOH status(0x21) keep 0x00 even charge-discharge 3 cycling? And Steven said that SOH status have been removed?

Thanks

George

0 George Yang2 over 4 years ago in reply to George Yang2

Prodigy 220 points

Hi Onyx/Steven

Any update for the questions? Thanks.

George

0 Onyx Ahiakwo over 4 years ago in reply to George Yang2

TI__Guru* 76230 points

hi George,

The gauge has to have learned qmax for SOH to be correct. FCC is calculated from qmax and if qmax isn't learned SOH will not be correct.

Can you attach your gg and log files showing the behavior if you are certain qmax is learned?

Thanks

Onyx

0 George Yang2 over 4 years ago in reply to Onyx Ahiakwo

Prodigy 220 points

Hi Onyx

"FCC is calculated from qmax and if qmax isn't learned SOH will not be correct."

--> Correct both 0x21(SOH status) & 0x20(SOH percetange)?

Just want to make sure and I will re-test and check the relationship between SOH(including 0x21 & 0x20) and QMAX_UP!

Thanks.

0 Onyx Ahiakwo over 4 years ago in reply to George Yang2

TI__Guru* 76230 points

Let us know.

thanks

Onyx

0 Onyx Ahiakwo over 4 years ago in reply to George Yang2

TI__Guru* 76230 points

Hi George

Thanks let us know the outcome.

regards

Onyx

0 George Yang2 over 4 years ago in reply to Onyx Ahiakwo

Prodigy 220 points

Hi Onyx

3 questions :

1. Qmax is learned and the SOH status(0x21) will be changed?

2. Qmax is learned and the SOH percentage(0x20) will be changed, and as the best is 100%?

3. If design capacity > real battery capacity, the SOH status would not change and percentage would never be 100%, correct?

(ex : design capacity set as 2600mAh, but battery cell only 2450mAh)

Thanks.

0 George Yang2 over 4 years ago in reply to George Yang2

Prodigy 220 points

Hi Onyx/Steven

Any update for my questions? Thanks!

0 Andy Liu (BMS) over 4 years ago in reply to George Yang2

TI__Guru 52115 points

Hello George,

For SOH, make sure your BAT_DET bit is set. Please refer to the TRM for battery insertion protocols.

Power management

Power management forum

BQ27426: State of Health function enable