When connet the battery it drains the power from the ac adapter of 19.5v

[Irfan-1]

When i add the ac adapter it shows 19.5v but when i add my battery to the laptop it slowly drains the voltage from the ac adapter one by one and takes it down to 0v, is that normal? if not any reason why it happens?

[Hawks_Eye]

Hi @Irfan-1 

Welcome to HP Support Community!

We noticed that this thread hasn't had any updates in a while since your original post; while this is rare, we didn't want this post to remain unanswered, so, here's the solution to your query. We hope it helps you and everyone viewing this post 😊

Thank you for explaining the situation so clearly. I’m really sorry you’re dealing with this—it’s genuinely concerning when a laptop’s battery causes the AC adapter voltage to collapse. That behavior is not normal, and it typically points to a shorted battery circuit, faulty power management IC, or a damaged charging rail on the motherboard.

Here’s a breakdown of what’s likely happening and why:

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What the Voltage Drop Indicates

• When the AC adapter shows 19.5V without the battery, it means the adapter and DC jack are functioning normally.
• When you connect the battery and the voltage drops gradually to 0V, it suggests the battery is drawing excessive current or triggering a protective shutdown in the power delivery circuit.
• This can occur if:
  • The battery has an internal short or failed cell.
  • The charging controller on the motherboard is damaged or misbehaving.
  • The MOSFETs or current sensors in the power rail are failing to regulate flow.

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What You Can Do Next

 

1. Test with a Known-Good Battery

If available, try connecting a compatible battery from another unit. If the voltage holds steady, the original battery is likely defective.

 

2. Inspect the Battery Connector and Pins

Look for signs of corrosion, bent pins, or residue that could cause a short. Clean gently with isopropyl alcohol and a soft brush.

 

3. Measure Voltage at the Battery Terminals

Using a multimeter, check whether the battery outputs any voltage when disconnected. A completely dead or shorted battery may show 0V or unstable readings.

 

4. Run HP UEFI Diagnostics (If System Powers On Without Battery)

• Power on the laptop without the battery.
• Press Esc repeatedly, then F2 to enter diagnostics.
• Run the Battery Test and AC Adapter Test.

You can find detailed steps on HP’s Battery Troubleshooting Guide and AC Adapter Diagnostics.

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If the laptop refuses to power on with the battery connected and the adapter voltage collapses every time, the safest path forward is to replace the battery and, if needed, have the motherboard inspected for charging circuit faults. 

Let’s make sure your system gets the stable power it deserves.

Please mark this post as “Accepted Solution” if the issue is resolved, and if you feel this reply was helpful, click “Yes”.

Thanks for being part of the HP Community!

Regards,
Hawks_Eye