HP Omen 15-ax014ns - Don't charge or discharge battery!!

[tesnic]

Hi community! I've a strange case.. Laptop HP Omen 15-ax with 11,55V new battery that dont charge or discharge. The battery coil with the battery connected ia 12,25V. All mosfets seems ok, i verify dont exist any short.... The laptop power on OK, even only with battery but it dont charge. I verify the volatges on BQ738H and it seems ok....i read the 2.2.3. Low voltage on battery charging rail post, but i dont be able to found the issue... Any idea guys? Thanks a lot!!!!

[mon2]

Is the battery detected in Windows? If not, confirm the voltage to ground of each pin on the battery connector. Meter in DC volts scale (20v or higher is ok); measure the voltage to ground of each pin on the battery connector.

Interested in the SMBUS / I2C SCL and SDA lines (pins #8 and #9 on the connector). These pins are used to extract the details of the battery pack (serial #, charge #, etc.).

[tesnic]

Thanks legend! The battery is recognized by Windows, it seems charge by 5 seconds and stop, show as connected and the 50% level of charge. I can unplug the ac connector and works with battery. The pins 8 and 9 are 3,14-3,21V moving interval on the battery connector

[mon2]

Remove all power. Meter in lowest resistance mode. Measure the path resistance between pins 12 and 13 of the charger ic pins.

[tesnic]

Between pin 12 and 13 of the BQ charger IC is 16ohms resistance

[mon2]

This is a good measurement. Nothing wrong with the current sense loop resistors in this path.

Still with no power, measure the resistance of the DCin mosfet (PQ1003).

Measure:

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

Post each measurement and the units of measure from your meter. Checking if the mosfet is leaky. Each measurement should be a high resistance value. PS: Do review the charger sticky posted above by piernov. Good reading.

[tesnic]

Measurements PQ1003:

source (1-2-3) & drain (5-6-7-8) = 8,80K ohms
source (1-2-3) & gate (4) = 0,6M ohms
gate (4) & drain (5-6-7-8) = OL

These mosfet, receive 25V on gate and open the 19.5V between source and drain

[mon2]

Measure carefully the voltage to ground of ILIM on the charger IC. This voltage defines the max charge current. Are you able to source another known good battery perhaps from Amazon? The battery can be returned if not required.

[tesnic]

The ILIM pin of the charger IC shows 1V aprox, with and without the battery plugged. I will try another battery, this is a new battery from Amazon. The original is 0V and i'm not capable to charge it... The new one shows 11,87V, and Windows read abou 50%. The coil battery shows 12,25V with the new battery, and 5.85V with the 0V battery, the same as unplugged any battery...I changed the BQ IC about 3 times, the same results....

[mon2]

As a general comment - flux the charger IC well and apply ample heat with low air pressure to allow for the IC to sink into the melted solder on the pads. Be sure there are no visible solder shorts.

After the above, carefully (!) measure the voltage to ground of each pin with the power adapter & battery connected. Then repeat with only the battery connected (no adapter). Post the complete list of the battery charger pins.

Measurements PQ1003:

source (1-2-3) & drain (5-6-7-8) = 8,80K ohms
source (1-2-3) & gate (4) = 0,6M ohms
gate (4) & drain (5-6-7-8) = OL

The source / drain resistance is considered to be very low for a known good mosfet. Review the same resistance check against the other mosfets to compare. Suggest to flux and remove this mosfet after the review and check the same source / drain resistance while the mosfet is on your work table. Do you still see a low resistance across these pins? It should be replaced. The contradiction is that you have 25V on the gate pins which usually will stop if the mosfet is defective but do test.

[tesnic]

Ok thanks! I change the mosfet PQ1003 and the same resintance values in the board. Off the board, the resistace is higher. It seem works ok.... About the charger IC, i have to do the measurements with the laptop powered on? or only whith the ac adpatar / battery plugged in?

[mon2]

Ok. Then this mosfet cannot be blamed but good to review. Given that the battery cannot charge, the battery should be considered a suspect. Yes, do test with another known good battery or even a different vendor on Amazon. This should rule out the battery as the suspect. Next is to review the voltage to ground of each pin on the charger IC with the power adapter & battery installed.

If the battery is able to power the laptop (with no power adapter), then the battery gauge should show the depletion of the battery charge as you continue to use the laptop while being powered off the battery alone. If it does not, then the BMS (battery management system board which is buried inside of the battery pack) is defective. The battery gauge should not be stuck @ 50%. Pins # 8 & 9 are linked to the battery charger IC and responsible for the battery statistics like the amount of charge, etc. Be sure the contacts of the battery are mating to these pins. There are public projects based on Arduino on how to communicate with the battery pack to retreive similar juicy parts of the battery.

Next, meter in lowest resistance scale. Measure the resistance from pin # 8 of the charger IC to the battery connector (remove the battery for now) - pin # 8. This is to confirm the SDA pin is mating from the charger IC to the battery connector. No power to the board during these resistance checks.

Repeat for pin # 9 to # 9 (SCL pin).

[tesnic]

The readings about SCL pin and SDA pin, from IC to same pins on battery connector, are both 328 ohms.. I buy another battery from Amazon to try it...

[mon2]

The resistance is ok since there are 330R (330 ohm) resistors in series with each of these lines (SCL / SDA) as shown near the battery connector.

[tesnic]

I just bought a new battery, same issue.... Windows detect it connected, but dont charge it... The voltages in the battery coil, the sames, shows 11,57V with the new battery, and 5.85V without it... Any idea?? Thanks again for your help!!!

[mon2]

Which BQ charger IC was used for the replacements? Is it exactly the same as the original?

[tesnic]

Yes, the tipical BQ24738H ....

[rogfanther]

Just as something to check : are you using the original HP charger ? This model seems to have dectection on the connector, and the charger could be inadequate or faulty/not recognized, and then the board wouldn´t charge the battery ?

[tesnic]

It's the charger original i know HP prefer original ones to charge it.... I test it and seems ok. I notice the B_TEMP_MBAT signal, is 3.3V but when plug the battery, drop to ground.. Is normal?? And what is the signal of BQBATDRV suposed to be? I have 5,8V and go to gate and source of the PQ1001... i dont understand how is suposed to open these mosfet...If i quit these mosfet, nothing different happens...

[rogfanther]

Does it show on bios something as "charger connected" or "Unknown charger" or something like that ?