Battery charges till some specific percentage % ?

[usyusy]

hi to all dears,

if any battery is charged upto some specific percentage like Dell Latitude 3330 charges upto only 34%.

what could be its possible reason...,regards

[mon2]

Re: Battery charges till some specific percentage % ?

Hi.

1) try a different battery - same or different results ?

2) Could be a fault in the charger IC = PU401.

Meter in voltage mode.

Measure the voltage of

PBAT_SMBCLK
PBAT_SMBDAT
PBAT_PRES#


3) The charger operates with a current sense circuit:

ISL88731_CSIP_R
ISL88731_CSIN

to gauge if enough / too much current is being consumed by the battery pack.

If this leg of the circuit is faulty, the wrong readings will lead to the charger shutting off the charging mosfets @ PU4003 & PU4004.

Remove all power / no battery.

Meter in resistance mode.

Confirm that the above 2 lines reach the charger IC. Confirm the resistance of PR4018 (if present).

Also, check the resistance of the high side & low side mosfets (PU4003 & PU4004) as follows:

source (1-2-3) & drain (5-6-7-8)
source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)

Post the readings for both mosfets. If the mosfet readings are low, then the mosfet is defective which will also cause such events.

Use the lowest scale on your meter to measure the mosfets.