BQ35100: How to use it for measuring capacity of 38Ah batteries( 2x19Ah in parallel)?

RAJARSHI ROY

Part Number: BQ35100

Hello All,

We were looking to implement 38Ah Lithium Thionyl Chloride(LTC) batteries(2x19Ah in parallel) in a particular project and gauge its capacity but the BQ35100 has its maximum capacity of 32Ah.

Kindly suggest a method by which we can measure its capacity in EOS mode.

Also, does TI have a separate IC for measuring LTC batteries of higher capacity?

over 5 years ago

0 Wyatt Keller over 5 years ago

TI__Guru** 105760 points

Hello Rajarshi,

The BQ35100 should be able to handle up to a capacity of 65Ah in the TRM: https://www.ti.com/lit/ug/sluubh1c/sluubh1c.pdf?ts=1591382509909&ref_url=https://www.ti.com/product/BQ35100

You should be able to upload your batteries ChemID and the gauge will perform a look up on that ChemID to determine the remaining capacity of your battery depending on it's internal resistance.

Sincerely,

Wyatt Keller

0 RAJARSHI ROY over 5 years ago in reply to Wyatt Keller

Prodigy 140 points

Dear Wyatt,

I've checked the TI website and it says maximum 32000mAH. So, I'm a bit confused about which data is correct?

0 Wyatt Keller over 5 years ago in reply to RAJARSHI ROY

TI__Guru** 105760 points

Hello Rajarshi,

Yes you are correct, the max is 32000mAh, I apologize I looked at the wrong register.

We currently don't have a gauge that can support up to that capacity for the Lithium Thionyl Chloride chemistry.

Sincerely,

Wyatt Keller

0 RAJARSHI ROY over 5 years ago in reply to Wyatt Keller

Prodigy 140 points

Hello Wyatt,

So, there's no way we can use two 19Ah batteries in parallel and use a fuel gauge?

Is there any other method by which we can use these batteries parallelly? I understand we can use a 'scaling down' method when we are using these batteries in series.

Kindly Suggest.

Regards,

Rajarshi Roy

0 Wyatt Keller over 5 years ago in reply to RAJARSHI ROY

TI__Guru** 105760 points

Hello Rajarshi,

We don't currently have a gauge that can support over 32Ah battery with that chemistry, even with scaling down or other configurations it could lead to inaccurate gauging.

Sincerely,

Wyatt Keller

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BQ35100: How to use it for measuring capacity of 38Ah batteries( 2x19Ah in parallel)?