About over discharged battery and bq25100H

Satoshi

Guru 19645 points

When I make them connect the battery which did over discharge, it can't charge any more.

Is there a measure?

When battery protection IC connects the battery which becomes Cut-Off and supplies 5V, over discharge turns on FET for protection,

and starts to see the battery voltage, but a charge isn't done.

Therefore 5V is connected, a battery consumes an electric current, and battery protection detects over discharge, and disable again.

When 5V is turned OFF→ON before a device detects over discharge, it was charge.

【Additional Information】

・Battery protection IC：S-8211CDO-I6T1U (SII)

S-8211C web

S-8211C datasheet

・VBAT is less than 3.3V.

　(Customer think that the battery remain is less than 5%.)

・A charge is suspended perfectly.

　→The current of the 5V power line was 0mA～1mA. 　

　→When they'll be left alone, the battery voltage becomes off once again by over discharge.

Best regards,

Satoshi

over 10 years ago

0 Wenjia Liu over 10 years ago

TI__Expert 7730 points

Satoshi-san,

The battery protector needs sufficient amount of current to close once it is opened. What is the battery capacity and what is the pre-charging current programmed to?

Thanks,Wenjia

0 Satoshi over 10 years ago in reply to Wenjia Liu

Guru 19645 points

Dear Liu-san

Thank you for reply.

I answer your questions.
①Battery capacity is 200mAh
②Pre -charge current is 9.7%.
(2.9kΩ Pre-charge resister)

5V supply can drive more than 500mA to battery.

Best regards,
Satoshi

0 Wenjia Liu over 10 years ago in reply to Satoshi

TI__Expert 7730 points

Satoshi-san,

Can you try increasing the Pre-charge percentage to 20% or higher? It is possible that the pre-charge current is too small to close the battery protector.

Thanks,

Wenjia

0 Satoshi over 10 years ago in reply to Wenjia Liu

Guru 19645 points

Dear Liu-san

Customer changed Pre-charge:20%(6.2kΩ), but it was not charge.
In this case, customer messured on 5V supply's Current, it was 850μA.

Additional information, Tester connected between 5V supply to battery, it sometimes charge safely.
(I think that it depend on change of resistance value (a few Ω).

When there is a point which should be confirmed, please let me know.

Best regards,
Satoshi

0 Wenjia Liu over 10 years ago in reply to Satoshi

TI__Expert 7730 points

Satoshi-san,

Do you have a schematic or block diagram of the system? It is not very clear to me how the charger is connected and operated.

Thanks,

Wenjia

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About over discharged battery and bq25100H