Battery charging percentage errors and unexpected shutdowns

[peoy9714]

I am looking for expert guidance to identify the root cause of a recurring battery/power issue.

I replaced the laptop battery approximately 6 months ago, but I am now experiencing the following problems:

• The battery percentage sometimes gets stuck at a particular level while charging and does not increase.

• Restarting the laptop can cause the reported battery percentage to change suddenly and significantly.

• The laptop has unexpectedly shut down when the battery was showing around 20%.

• On one occasion, the battery dropped from 16% to 7% in approximately 30 seconds, and then remained at 7% even while connected to AC power.

• Windows also shows frequent AC/Battery status changes, sometimes only seconds apart, even though I am not physically disconnecting and reconnecting the charger.

I have already performed the standard troubleshooting recommended by HP experts on similar Support Community posts, including:

• HP PC Hardware Diagnostics (UEFI) battery testing

• Battery seating/physical inspection

• Checking power settings

• Performing a hard reset

• Updating BIOS and drivers

• Battery testing/calibration

The issue is still occurring.

I have also generated a Windows Battery Report using:

powercfg /batteryreport /output "%USERPROFILE%\Desktop\battery-report.html"

I can provide the complete battery report for detailed analysis.

The current report shows:

• Design Capacity: 46,200 mWh

• Full Charge Capacity: 42,257 mWh

• Cycle Count: 1

Given that the battery was replaced only 6 months ago, I would particularly like to understand whether the symptoms point to something beyond ordinary battery wear, such as an issue with the battery/BMS, battery communication, battery connector, charging circuitry, Embedded Controller (EC), BIOS/firmware, or motherboard power-management circuitry.

I am not looking for another repetition of the standard battery troubleshooting steps, as I have already completed those.

Could an HP expert please advise me on the next-level diagnostics that can distinguish between:

1. A defective/replacement battery or BMS issue

2. Incorrect battery-state reporting/calibration

3. AC adapter or charging-circuit problems

4. Battery connector/communication problems

5. EC/BIOS/firmware or motherboard power-management issues

I can immediately provide the battery-report.html as well as any specific Windows Event Viewer logs, PowerShell/CMD outputs, or HP diagnostic results required.

I would really appreciate help identifying the actual root cause before replacing the battery again.

[Deep_World]

Hi  @peoy9714 
 
Welcome to the HP Support Community!

Thanks for reaching out!

I understand that you want to identify the actual source of the incorrect battery readings and power interruptions before replacing another component.

Based on the figures shared, the reported full-charge capacity is approximately 91% of the original design capacity. Capacity alone, however, does not confirm that the battery or its internal Battery Management System is operating correctly. The sudden percentage changes, shutdown near 20%, and repeated switching between AC and battery power could indicate inconsistent power delivery or communication between the battery, adapter, charging circuit, and system firmware.

To help narrow this down, kindly provide the following information:

• The exact laptop model and product number. This can usually be found on the label underneath the laptop or by pressing Fn + Esc
• Is it an original HP battery, and does HP PC Hardware Diagnostics identify it correctly?
• What result and status were shown by the latest UEFI Battery Test, including any Failure ID?
• Are you using the original HP AC adapter, and what is its wattage?
• Does gently moving the charging connector cause the AC status to change?
• Does the laptop shut down unexpectedly while it is sitting in the BIOS or HP UEFI Diagnostics screen, or only while Windows is running?

Since the usual troubleshooting has already been completed, kindly try the below specific checks:

1. Run the HP AC Adapter Test separately

Restart the laptop and repeatedly press Esc, followed by F2, to open HP PC Hardware Diagnostics UEFI. Select:

Component Tests > Power > AC Adapter Test

Kindly note the result, adapter wattage if displayed, and any Failure ID. Testing the adapter independently may help determine whether the repeated AC/battery switching is related to unstable adapter detection rather than battery capacity.

2. Compare behaviour outside Windows

Leave the laptop in the BIOS setup screen or HP UEFI Diagnostics screen while connected to AC power, and observe whether the charging indicator or power state continues to change.

If the behaviour also occurs outside Windows, that would make a Windows power-plan or software-reporting issue less likely. It would support checking the adapter, DC-in connector, battery connection, charging circuit, Embedded Controller, or system board.

3. Check battery and adapter details in UEFI

In HP PC Hardware Diagnostics, open the battery details and record the following where available:

• Battery status
• Battery serial number
• Remaining and full-charge capacity
• Cell voltage information
• Calibration status
• AC adapter status
• Any Failure ID or warning code

HP recommends recording the battery status and Failure ID when a battery test fails, as this information can be used by HP Support when reviewing repair options. The official procedure is available here: HP Notebook PCs – Testing and calibrating the battery.  

The capacity figures provided do not resemble a simple severe capacity-loss pattern by themselves. The more significant symptoms are the abrupt percentage changes, shutdown while charge is still displayed, and rapid switching between AC and battery status.

I hope this helps.