BQ35100: Custom battery pack monitoring

Maurizio Bottaro

Part Number: BQ35100

Tool/software:

Dear TI Support,
I'm developing a custom board using BQ35100 device.
My goal is to monitor a custom battery pack with 2 D-cells in parallel with a lithium battery also in parallel (due to the peak current needed by a GSM modem).
Is the BQ35100 a suitable device for this special application or is intended to monitor only a single battery?
This is the custom battery pack:

In case of affirmative answer, I'm looking for a procedure to build this battery pack with the integration of BQ35100.

Thank you the the support!

Looking forward for your reply

Regards,
M

4 months ago

0 Maurizio Bottaro 4 months ago

Prodigy 20 points

D-cells are made of Lithium Thionyl Choride (SL-2780 Tadiran), the backup lithium battery is made of Lithium Intercalated Compounds (HCL-1530 Tadiran).

0 Alan Frias 4 months ago in reply to Maurizio Bottaro

TI__Mastermind 27195 points

Hello Maurizio,

This wouldn't work since your system needs something called chemID and using two different battery chemistry will mess up every aspect of your battery gauge information gathering system. Best solution is to have the entire pack be the same cell.

Thank you,
Alan

0 Maurizio Bottaro 4 months ago in reply to Alan Frias

Prodigy 20 points

Dear Alan,
thank you for the fast reply.
Maybe this could be a better solution.
In this way I'm excluding the backup Li-cell monitoring only the battery pack built with 2 x D-cells.
The final battery pack is having this layout:

Can you confirm this could be a way to solve my problem?
Let me know, thank you!
Have a nice day!
M

0 Alan Frias 4 months ago in reply to Maurizio Bottaro

TI__Mastermind 27195 points

Hello Maurizio,

This would still not be a viable solution, the biggest reasoning for this either than using different cell part number is that you can't use a non-rechargeable cells with recharge cells together on the same battery gauge.

Thank you,
Alan

0 Maurizio Bottaro 4 months ago in reply to Alan Frias

Prodigy 20 points

Hi Alan,
Ok, understood. In this particular case the only working choice is using a gauge per battery.
Assuming that it couldn’t be so important to estimate the battery residual charge, can I use this device as a Coulomb counter measuring Ah or it’s better to consider other kind of devices?
The application runs in sleep for the 80% of its life.
Let me know your opinion, thank you!
Regards,
M

+1 Alan Frias 4 months ago in reply to Maurizio Bottaro

TI__Mastermind 27195 points

Hello Maurizio,

Yes this device would be be able to do coulomb counting and be able to tell how much current is drained from the system.

Thank you,
Alan

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BQ35100: Custom battery pack monitoring