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I have acquired two (identical) used HP laptop power supplies compatible with and for two identical HP branded laptops in an office. When power is cut to the supply, the attached computer immediately shuts down cold.

I imagine the power supplies must be faulty for this to be the case, but both supplies are exactly the same in this behaviour, perhaps there is a voltage spike that the laptop is protecting itself from.

Is this a common fault? Could it be water damage? Do some supplies just do that and it's annoying but normal?

Update:

Laptop model: HP Elitebook 8540w

Firmware initially not updated, after solution: F.60 Rev.A

Solution did not work until the battery was sufficiently discharged.

Update 2:

With battery fully charged, solution reverts and issue re-emerges as before.

Update 3: Additional information

The problem was compounded with the installation of a new battery. The issue arises when the connected charger is disconnected from mains power. The computer with no warning immediately shuts down. It does not occur when the charger is disconnected from the laptop first.

The problem is unlikely to be OS related as it can be forced to occur even when the the boot menu is displayed.

More specifically the shutdown occurs when the battery is full, if it is charging from part-full, the problem does not occur.

When the computer is in hibernate mode, the issue does not occur, when it is fully powered, it does, even if only up to the boot screen.

This is a high-priority issue as I work in places where mains power is intermittent, for periods longer than when the battery itself can sustain the device.

The first solution that appears to have worked for one of these two identical computers is a BIOS update. That machine no longer has the fault. The second machine retains the fault even after upgrade.

The first machine had its BIOS upgrade done via USB stick, the second used the HP Windows utility.

Hibernate or On | Low/high voltage pulled first | Battery at partial/full charge : Fault?

Hib | LV | P : No

Hib | LV | F : No

Hib | HV | P : No

Hib | HV | F : No

On | LV | P : No

On | LV | F : No

On | HV | P : No

On | HV | F : Yes

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    "The problem is unlikely to be OS related as it can be forced to occur even when the the boot menu is displayed." it's so good when people actually perform appropriate troubleshooting. I don't know what the Answer is, just wanted to say that. A small Uninterruptible Power Supply might be a good idea for you.
    – MountainMan
    Commented May 8, 2019 at 15:23
  • Cheers Chris, I've considered that though it makes the things a touch less portable..! Also reticent about dropping more money on what are relatively old machines. Am just frustrated that I recycled the old batteries before finding this issue, and don't know where to find batteries guaranteed to work.
    – J Collins
    Commented May 8, 2019 at 15:33

2 Answers 2

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As it turns out, the replacement batteries are the root cause.

Replacement batteries from two more reputable manufacturers both work just fine. Incidentally the problem batteries marked as 5200 mAh are in fact 4400 mAh by Samsung when viewed through software, so falsely marketed and illegitimate. The batteries at this link I would not recommend.

This and this battery both work and have the capacity advertised when viewed in software.

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I don't believe this is a charger issue. Especially since it's doing it on both of them.

This sort of behaviour can be found on laptops with faulty or malfunctioning batteries. But before buying a new battery, there's something you could try.

  • Head to your power options and create a new, custom power plan. This has been known to fix the issue.

If this doesn't work, it could point towards a firmware issue. In this case, i would suggest that you update your BIOS. This is known to fix any firmware issues. To find the latest BIOS update, pop your motherboard model into google and you'll usually find a page from the manufacturer with all the latest drivers on.

Unfortunately, if these don't fix the issue, i would suggest that you buy a brand new battery for your laptop. If you do this, please make sure it is an official battery for that exact model of laptop.

EDIT: In this case, it turned out to be a firmware issue. Updating the BIOS seems to have fixed the issue.

EDIT 2: The issue has unfortunately appeared back on another laptop.

EDIT 3: The issue turned out to be falsely advertised batteries.

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    This is interesting. The batteries were replaced at the same time, both with exactly the same replacement battery. The batteries are not exact HP replacement parts but of course claim to be drop-in replacements. Could it be to do with how the battery switches form charging to discharging?
    – J Collins
    Commented May 7, 2019 at 15:02
  • I would suggest that you take a look at your power settings. Be sure to try my suggestion and create a custom power plan.
    – NiallUK
    Commented May 7, 2019 at 15:04
  • Is it true of Windows 7? Would I need to essentially delete the built-in power settings? Can they be replaced? Perhaps you could send through a reference about this.
    – J Collins
    Commented May 7, 2019 at 15:16
  • Certainly. I have linked an article on how to create a custom power-plan in windows 7. Source
    – NiallUK
    Commented May 7, 2019 at 15:27
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    Great content Niall, I will update with some results if I find any conclusive solutions based on this.
    – J Collins
    Commented May 7, 2019 at 15:59

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