Min. battery charging and discharging current detected by BQ27425-G2B

Sunil Dhaduk5

Other Parts Discussed in Thread: BQ27425-G2B, BQ27426

Hello,

I want to know that what is min. battery charging and discharging current, bq27425-g2b can detect as 10mOhm sense resistor is inbuilt to this chip/

In our application, battery discharging current is very low (~4 mA). Can bq27425-g2b can detect this discharge current?

How bq27425-g2b measures state-of-charge of battery? For that it is compulsory that battery must be in charging or discharging mode?

over 7 years ago

0 Dominik Hartl11 over 7 years ago

TI__Guru 51346 points

The current resolution is 1mA so a 4mA current can be detected but the resolution may be a problem for your application.

0 Sunil Dhaduk5 over 7 years ago in reply to Dominik Hartl11

Prodigy 160 points

Thanks Dominik,
What is min. battery charging and discharging current that bq27425-g2b can detect?
How bq27425-g2b measures state-of-charge of battery? For that it is compulsory that battery must be in charging or discharging mode?

0 Dominik Hartl11 over 7 years ago in reply to Sunil Dhaduk5

TI__Guru 51346 points

The minimum current is 1mA.

The bq27426 is a better solution because it uses an external sense resistor which allows you to scale the current measurement for low current application like yours. Using a 100mOhm sense resistor instead of the 10mOhm sense resistor scales the current by 10, so your 4mA looks like 40mA to the gauge. You'd configure all parameters that depend on this measurement with the scaling factor (e.g. capacities).

SOC is determined by measuring relaxed state voltage and counting charges during charge or discharge. It uses chemistry info (OCV tables, impedance tables) together with these measurements to calculate SOC.

0 Sunil Dhaduk5 over 7 years ago in reply to Dominik Hartl11

Prodigy 160 points

Hi Dominik,
Thanks for your support...

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Min. battery charging and discharging current detected by BQ27425-G2B