BQ27421-G1: The question about gauge

Leo Yang

Expert 3075 points

Part Number: BQ27421-G1
Other Parts Discussed in Thread: BQ40Z50, BQ28Z620, BQ34Z100

Hi team,

If we change the battery vendor in same spec, should it need to train the gauge again? Is there any issue?

If we used two series battery up to 7.4V, could you recommend a solution? Please let us know the design. Thanks.

Thanks,

Leo

6 months ago

0 Adrian 6 months ago

TI__Mastermind 18971 points

Hey Leo,

As long as the battery has the same characteristics (model, nominal voltage, capacity, etc) then you should not have to complete the learning cycle again. If you are using two batteries in series then I would recommend the BQ28z620 or the BQ40z50. The BQ27421 is a single cell gauge.

Regards,
Nick Richards

0 Leo Yang 6 months ago in reply to Adrian

TI__Expert 3075 points

Hi Nick,

Thanks for answering. If 2 series batteries are in one package, do we have a solution for only sense the total voltage (5.5V~8.4)?

Leo

0 Adrian 6 months ago in reply to Leo Yang

TI__Mastermind 18971 points

Hey Leo,

If the 2 series batteries are in one package and there is not a way to get a direct connection to each individual cell, then I would have to recommend the BQ34Z100 which is a top of stack gauge.

Regards,
Nick Richards

0 Leo Yang 5 months ago in reply to Adrian

TI__Expert 3075 points

Hi Nick,

1. Could you let me know how BQ28z620 do the battery balancing? The customer will use 2 batteries in series.

2. Do we perform over charge and over discharge protection? How we do the protection?

Thanks,

Leo

0 Adrian 5 months ago in reply to Leo Yang

TI__Mastermind 18971 points

Hello Leo,

To learn more about cell balancing, please read chapter 9 of the TRM.
Yes, the gauge has over change and over discharge protection. Please read chapter 3 of the TRM to learn more about this.

Regards,
Nick Richards

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BQ27421-G1: The question about gauge