BQ24103: Not able to enter precharge

Hello team please help me out here

Hi Shreenidhi,

Please set CMODE Pin to GND for pre-charge, set Cmode Pin to high for fast charge.

Alen Chen

Hello Allen

I am using Bq24103

I think the Cmode pin is not available in case of my ic

Hi Shrenidhi,

Sorry , I thought you are using bQ24113.  How much is the pre-charge current ? What is VBAT during precharge. I thinks BQ24133 was in short charge phase(see the picture below).

Alen Chen

We are using BQ24103 

Vbat ( Battery voltage )  is = 4.75V  when i am connecting it in the circuit 

Pre charge current = 133mA , 

Fast charge =  1.3A

However i see the battery still doesnt enter pre charge despite being at 4.75V. 

It enters directly 1.3A current .

Also can you please help me understand how do i decide / how do i set the voltage at which the battery shall enter pre charge current ?

 

Hi Shrenidhi,

Understood you said. It because of the capacity of the battery is very low when Vbat lower than 3V/Cell and the internal resistance is very high. So you can't see it easily. Please use electronic load to clam VBAT to 5V. Than try a gain.

Alen Chen

Hi chen 

the issue is that battery charger is not entering the Pre charge mode 

it always is giving 1.3A of charging current even when the battery is in deep discharge 

Also can you please help me understand how do i decide / how do i set the voltage at which the battery shall enter pre charge current ?

Hi Shreenidhi,

It means the battery voltage go up 6V very quick, so please make sure the voltage is lower than 6V if you want to see pre charge.

Alen Chen