Charging issue..

[ashiq]

DABKXDMB8F0 , motherboard the battery voltage is fluctuating like 8.66, 8.55,8.7V
The charging ic is BQ24780s,
Without battery connected also there is 8v in the battery connector is it normal ?
the SDA and SCL also fluctuating without battery connected also ..

[mon2]

SMBUS lines will toggle and fluctuate as the traffic is placed on these lines. Does the motherboard power up normally and boot to the operating system? In Windows, is the battery detected?

[ashiq]

SMBUS lines will toggle and fluctuate as the traffic is placed on these lines. Does the motherboard power up normally and boot to the operating system? In Windows, is the battery detected?

the system will on and off suddenly.

[ashiq]

the 8v comming without battery is it normal?

[mon2]

That battery charge voltage will enable if pin #15 (BATPRES# is logic low = 0V). If this pin #15 = logic high then the battery charge voltage will disable.

Sometimes, the logic board designers will hardwire pin #15 to ground. Confirm what you have onboard.

Review the charger ic datasheet on the operation details.