HP ProBook 445 G8 Battery not charging

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  • Julian Bailey
    Member
    • Sep 2024
    • 24
    • UK

    #1

    HP ProBook 445 G8 Battery not charging

    Hi all

    We have in a HP ProBook 445 G8 laptop with AMD Ryzen 7 CPU. When power is connected the power LED light blinks 5 times then stops. Normally HP laptops will blink this LED 10 times as it does a self test when the AC adaptor is inserted. So there must be some sort of short somewhere.

    The battery doesn't charge, and is erratic on the MM voltage. Bench PSU LED pulsates when the battery is connected also. So the fault must be on the charging circuit?

    I have gone around the board with a MM and cant find anything

    Windows shows the battery fine, but no charging symbol.

    If battery is disconnected from the motherboard the LED on the charger stays normal and the laptops powers up fine just using the HP charger.

    Battery charges fine in another laptop.

    So must be a charging circuit fault. Thing is I cant find a schematic of this motherboard

    Motherboard is: DA0X9QMB8E0 Rev E

    I`m wondering if its the BQ24800 chip? Seems to control battery charge etc:

    The BQ24800 is a buck battery charge controller that performs a number of functions, including:

    Battery charging and discharging
    The BQ24800 can quickly transition between charging and discharging batteries to prevent adapter crashes.

    Battery boost mode
    When no adapter is present, the BQ24800 can support battery-only boost mode.
    System power source selection

    The BQ24800 uses two charge pumps to automatically select the system power source.

    System power management
    The BQ24800 monitors system power, battery discharge current, and adapter current. It can then throttle back CPU speed or reduce system power when needed.

    Charge voltage and current regulation
    The BQ24800 can regulate charge current and voltage through SMBus.

    The BQ24800 can charge 1–4 series Li+ cells. It has an input voltage range of 4.5–24 V and a programmable output of 2–4 cells charge voltage and 128-mA to 8.128-A charge current.

    Any ideas folks?

    Many thanks
    Last edited by Julian Bailey; 10-11-2024, 10:38 AM.
  • mon2
    Badcaps Legend
    • Dec 2019
    • 13829
    • Canada

    #2
    The BQ24800 is an improved version with same pinout as the documented BQ24780s. Review the voltage to ground of each pin on this charger ic and post all measurements in a table with their PIN numbers and functions.

    The usual dcin mosfets are suspects. See the sticky above by piernov.

    Test the resistance across the mosfets (with no power). Each measurement should be hundreds of kohms or more.

    In the first paragraph, the adapter fails to power the board. Later in the post, the adapter does work. The adapters always if the battery is attached?

    https://www.ti.com/lit/ds/symlink/bq...lsrc%253Daw.ds

    Comment

    • Julian Bailey
      Member
      • Sep 2024
      • 24
      • UK

      #3
      Originally posted by mon2
      The BQ24800 is an improved version with same pinout as the documented BQ24780s. Review the voltage to ground of each pin on this charger ic and post all measurements in a table with their PIN numbers and functions.

      The usual dcin mosfets are suspects. See the sticky above by piernov.

      Test the resistance across the mosfets (with no power). Each measurement should be hundreds of kohms or more.

      In the first paragraph, the adapter fails to power the board. Later in the post, the adapter does work. The adapters always if the battery is attached?

      https://www.ti.com/lit/ds/symlink/bq...lsrc%253Daw.ds
      Thanks for the reply.

      The laptop powers on fine using the HP adaptor with the battery connected and also not connected.

      The laptop also powers on fine with just a charged battery plugged in.

      I will check the pin outs and reply with my findings.

      Thank you.

      Comment

      • Julian Bailey
        Member
        • Sep 2024
        • 24
        • UK

        #4
        The usual dcin mosfets are suspects. See the sticky above by piernov.

        Where is the above sticky sorry?

        Thank you.

        Comment

        • mon2
          Badcaps Legend
          • Dec 2019
          • 13829
          • Canada

          #5
          Laptop battery charging circuit - Badcaps

          Comment

          • Julian Bailey
            Member
            • Sep 2024
            • 24
            • UK

            #6
            Sadly the BQ blew a hole which also took out another chip on the other side causing it to blow a whole in the board

            RIP!​

            Comment

            • Julian Bailey
              Member
              • Sep 2024
              • 24
              • UK

              #7

              Comment

              • mon2
                Badcaps Legend
                • Dec 2019
                • 13829
                • Canada

                #8
                Still a bit of hope. It my be possible to repair. Flux the charger ic well and remove it after the solder is in liquid mode. Be patient.

                The mosfet burnt area is of a larger concern. Using wires, it should be possible to rebuild.

                Comment

                • Julian Bailey
                  Member
                  • Sep 2024
                  • 24
                  • UK

                  #9
                  Originally posted by mon2
                  Still a bit of hope. It my be possible to repair. Flux the charger ic well and remove it after the solder is in liquid mode. Be patient.

                  The mosfet burnt area is of a larger concern. Using wires, it should be possible to rebuild.
                  I wouldn't feel comfortable, if it was to work again, to go back in to the laptop.

                  I will however give it a go to see if it can be repaired purely for learning purposes only.

                  Thank you for your help mon2, it's appreciated.

                  Comment

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