BQ27Z561: Can we implement proper learning cycle when two batteries are connected in Parallel using BQStudio and bq27z561EVM-011?

Hello Parth,

Yes, you can. Make sure to update all parameters related to capacity(3000mAh) before starting the learning cycle.

Hello,

I have 2 queries regarding this question, please help me solve it.

1 - Can you tell me what is the exact procedure for learning cycle for double batteries, for single battery i am following below links but for double batteries is there any reference document of ti?

https://www.tij.co.jp/jp/lit/an/slua903/slua903.pdf?ts=1662442395794

https://www.youtube.com/watch?v=WAcxrGDb68g

2 -  And what parameters are you referring to?

For single battery we are updating parameters like charging voltage, nominal voltage, capacity, taper current, termination voltage, design voltage etc in data memory of gauge as per batteries' datasheet but for double batteries what should i do?   

Let's say in my application i am using 2 (1500mAh x 2)LiFePo4 batteries, in this case we can't multiply all these parameters by 2 and update it in data memory, Right?

So what parameters should i update in this case.

Your detailed suggestion would be helpful to me.

Thanks,

Parth

1. The procedure for parallel batteries is exactly the same. The chemistry match is done on a single cell and learning cycle performed using actual configuration.

2. The total capacity will need to be updated to match the parallel cells. Voltages parameters usually don't need updates. Taper current is your choice, so not directly related to the cell. Update design capacities and Qmax..See TRM section 4.7.1 QMax Initial Values

Here is a link to a guide that covers all aspects of gauge design www.ti.com/.../sluaa98

Hii,

Pardon me, I still don't get the entire process for learning cycle for multiple cells.

Can you provide me the list of parameters which i need to update into data memory of gauge before starting learning cycle so that i can successfully perform learning cycle for multiple cells.

Thanks,

Parth

Hello Parth,

The document mentioned above mentions the most critical parameters in section 1.2.1 Gauge Configurations Using BQSTUDIO

I would recommend that you review all data memory parameters before learning. This helps with understanding how the gauge works within the system and how the different features interact with and impact operation.

Have you obtained a chemistry match for your cell?

Hii,

Thanks for your reply.

No i haven't obtained a chemistry match yet as i am waiting for the batteries to be received from manufacturer so currently i am only gathering and learning everything about battery gauge.

Thanks,

Parth

Hello Parth,

Section 4 of the bq27z561 TRM  will help you understand more about how the gauge algorithm works.

OK, Thanks

I will try following all these steps as soon as i get all resources for same.