BQ34Z100: How to calculate SOH

Jason Dai

Expert 3720 points

Part Number: BQ34Z100
Other Parts Discussed in Thread: , GPCCHEM

Hello E2E,

We would like to know how BQ34Z100 ship calculate SOH.

Could you please share the app note or document to explain?

Sincerely,

Jason

over 5 years ago

0 Wyatt Keller over 5 years ago

TI__Guru** 105760 points

Hello Jason,

The BQ34Z100 uses the ratio of the Full Charge Capacity (FCC) and the Design Capacity of the battery to calculate the SOH.

Picture is from the TRM: http://www.ti.com/lit/ug/sluubw5/sluubw5.pdf?ts=1591292292859

Sincerely,

Wyatt Keller

0 Jason Dai over 5 years ago in reply to Wyatt Keller

TI__Expert 3720 points

Hello Wyatt,

I couldn't see any picture you posted on E2E.

Do we have any document to describe how we do SOH works and calculate?

Sincerely,

Jason

0 Jason Dai over 5 years ago in reply to Jason Dai

TI__Expert 3720 points

Hello Wyatt,

Finally, I found the information to describe how SOH works. The most important thing is the information of predicted FCC.

Another question is that what if user doesn't want to do the battery learning, how much battery gauge reporting tolerance between real and bq34z100-g1 reporting? any information we need to do the estimate?

Customer's application is 4S1P lead acid battery.

If battery learning is required, do we have any document to guide user step-by-step to complete the learning task?

Sincerely,

Jason

0 Wyatt Keller over 5 years ago in reply to Jason Dai

TI__Guru** 105760 points

Hello Jason,

Yes that's correct the predicted FCC is the critical portion that changes over time.

For maximum accuracy you would need to perform a learning cycle on the exact battery the gauge is working with. The accuracy depends on how close your ChemID that you have uploaded to the gauge matches your batteries.

Here's a guide for the learning cycle that might help" https://training.ti.com/how-perform-successful-learning-cycle-gauges

Sincerely,

Wyatt Keller

0 Jason Dai over 5 years ago in reply to Wyatt Keller

TI__Expert 3720 points

Wyatt,

Besides learning cycle, where could user find the default Chem_ID which has been stored in bq34z100-g1?

Customer wants to check how much different between the default value and the value in real battery.

Therefore, they could well judge if they really need to perform learning cycle or not.

Sincerely,

Jason

0 Jason Dai over 5 years ago in reply to Jason Dai

TI__Expert 3720 points

Wyatt,

Besides the question above, do we have any document to guide user step-by-step to set the configuration for 4S1P lead acid battery?

Customer could read default design capacity and design energy, but SOH value is 0.

Sincerely,

Jason

0 Wyatt Keller over 5 years ago in reply to Jason Dai

TI__Guru** 105760 points

Hello Jason,

They can input a battery profile in the GPCCHEM tool to match their chemistry ID with a preexisting profile.

I don't believe there's a guide specifically for that, but the EVM guide usually explains pretty well what steps to take: https://www.ti.com/lit/ug/sluu904a/sluu904a.pdf?ts=1591647543202&ref_url=https://www.ti.com/tool/BQ34Z100EVM

Sincerely,

Wyatt Keller

Power management

Power management forum

BQ34Z100: How to calculate SOH