BQ24725A: How Can I Revive a Deeply Discharge Li-Ion Battery with Battery Charger

Patrick Chew

Part Number: BQ24725A
Other Parts Discussed in Thread: BQ40Z50-R2,

Hi,

My customer has an integrated BQ40Z50-R2 smart battery (2series2parallel). I am designing a charger (BQ24725A) for this smart battery. The customer throws me a question, which i need the help from TI.

Question: If the smart battery somehow deeply discharged, is it possible the charger can revive the battery? How can it be done?

Thanks.

Patrick

over 5 years ago

0 Angelo Zhang87 over 5 years ago

TI__Genius 11850 points

Hi Patrick,

Yes, the BQ24725A can revive a deeply discharged battery. If VBAT < BAT_LOWV, then the BQ24725A can still charge the battery, but the charge current is limited to 0.5 A (assuming a default 10 mΩ sense resistor).

For example, if your ChargeCurrent() register setting = 1 A, then the actual charge current will be clamped to 0.5 A. After VBAT rises above BAT_LOWV, then the BQ24725A will charge the battery with the full 1 A ChargeCurrent() setting.

Best regards,

Angelo

0 Patrick Chew over 5 years ago in reply to Angelo Zhang87

Prodigy 130 points

Hi Angelo,

Thanks for your prompt reply.

1. If my battery voltage is far below the BAT_LOWV threshold, is there anyway to revive the battery?

2. Do you have any recommendation on the battery charger or smart battery to solve deeply discharge battery that below the threshold?

0 Angelo Zhang87 over 5 years ago in reply to Patrick Chew

TI__Genius 11850 points

Hi Patrick,

Even if VBAT is far below BAT_LOWV, my previous answer still applies. The BQ24725A can still charge the battery, but the charge current is limited to 0.5 A.

After VBAT rises above BAT_LOWV, the BQ24725A will start charging the battery with the full ChargeCurrent() setting.

Best regards,

Angelo

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BQ24725A: How Can I Revive a Deeply Discharge Li-Ion Battery with Battery Charger