Hp battery issue

[Milli11]

Hello HP Support,

I am experiencing a charging issue with my HP EliteBook 840 G8. When I connect the charger, the charging light starts blinking for a few seconds and then turns off. After that, the laptop stops charging.

Could you please help me identify the cause of this issue and advise me on how to fix it?

Thank you.

[NonSequitur777]

@Milli11,

Welcome to our HP Community forum!

On the HP EliteBook 840 G8, a charging light that blinks for a few seconds before turning completely off typically signifies a handshake failure between the power delivery (PD) controller and the AC adapter, a critically depleted or dead battery, or faulty controller firmware. The short burst of blinking shows that the laptop detects a connection, but it cuts power immediately when it fails safety checks or voltage matching.

Follow these diagnostics to isolate and fix the root cause:

1. Perform an EC (Embedded Controller) Hard Reset:

This discharges residual hardware capacitance and resets the underlying power logic chip that coordinates charging.

• Shut down the laptop completely.
• Disconnect the AC adapter and any other external USB devices.
• Press and hold down the Power Button for a full 30 to 60 seconds.
• Plug the AC charger back into the laptop (do not turn it on yet).
• Observe the charging LED. If it remains solid white or amber, let it charge for 15 minutes before booting up.

2. Isolate a Dead or Out-of-Sync Battery:

A failing or structurally degraded battery will often refuse to accept a charge to prevent overheating, causing the system board to terminate current input.

• Unscrew the base cover and safely disconnect the internal battery cable from the system board.
• Leave the battery completely unplugged.
• Connect your AC charger directly to one of the USB-C / Thunderbolt ports.
• Attempt to power the laptop on.
• The Result: If the laptop boots and runs normally using only the charger, your AC adapter and motherboard charging circuit are completely healthy. The battery itself needs to be replaced.
• Btw, is your battery bulging (swelling) in any way?  If it is, a sure sign that your battery is defective.

3. Diagnose the Charger and USB-C Logic:

The EliteBook 840 G8 charges via its Type-C ports.

• Switch Ports: This model features multiple Type-C ports. Try moving the charging cable to the adjacent USB-C port to see if a specific port has physical or internal line damage.
• Verify Charger Output: The EliteBook 840 G8 requires an absolute minimum of a 45-watt or 65-watt Power Delivery (PD) profile. If you are accidentally using a phone adapter, or if your charging brick's internal PD profile chip is broken, it will drop down to a base 5V output. The laptop will reject this, blink the status LED, and shut down the rail. Test with a known working, original HP 65-watt USB-C brick or an alternative 65-watt+ laptop adapter.

4. Address BIOS and Type-C Controller Bugs:

If the issue started after a Windows Update or system crash, the Type-C PD chip firmware may be frozen.

• If you can get the machine to boot briefly using the steps above, go immediately to the official HP Customer Support Page.
• Download and force-flash the latest BIOS firmware update available for your specific EliteBook 840 G8 variant. HP frequently publishes BIOS updates to fix handshake timing errors across their Type-C power rails.

Btw, if you disconnect the battery, does the laptop turn on and stay powered up under pure charger power, or does it stay entirely unresponsive?

Kind Regards,

NonSequitur777