Vostro 3520 shuts down adapter when battery is under 73 %

Question

For a few months I am having a problem with charging of my laptop, Vostro 3520. At first, when I unplugged it and plugged it again, it would not charge at all, (even with fully charged battery). So far, the power adapter, battery, motherboard, power cord, and battery cable have been replaced in my laptop. It solved the original problem, but now, when the battery capacity drops to 73% and I plug the power cable into the laptop, the adapter "shuts down" for some reason. The green indicator light on the adapter slowly turns off in this situation.

Then I have to unplug the adapter from the outlet and plug it back in (then the green light comes back on). If I plug the cable into the powered-off laptop, the battery starts charging normally, even if it’s below 73%.

If the battery is charged above 73%, there is no problem. I can unplug and plug the cabel again as many times as I want, and it starts charging again.

What could be causing this? Can BIOS be causing this? My version is 1.30.0. I have tried to revert it to default settings, but it did not help. Would reinstalling Windows help?

Neymar jr · Answer

It does not sound like a Windows issue. Since the adapter LED turns off completely, the charger is most likely going into protection mode because something on the power circuit is drawing too much current when the battery is below ~73%.

Because you already replaced the adapter, battery, motherboard, battery cable, and power cord, this points more toward either:

a charging-control / EC (Embedded Controller) firmware issue,
BIOS-related battery charging logic,
or a defective replacement part that behaves incorrectly under load.

A few things strongly suggest this is hardware/firmware related rather than software:

The problem happens before Windows even matters.
Charging works normally when the laptop is powered off.
The adapter physically shuts down (LED fades out), which usually means overcurrent or short-circuit protection is triggering.
The issue only appears below a specific battery percentage, which suggests charging-state logic rather than OS behavior.

Things worth trying:

Update BIOS to the latest version
BIOS 1.30.0 may not be the newest available. Dell sometimes fixes charging and EC behavior in later BIOS updates.
Run Dell diagnostics
Press F12 during boot → Diagnostics. Check for battery/AC adapter warnings.
Reset EC / flea power
- Disconnect charger
- Hold power button for 30 seconds
- Reconnect charger and test again
Check BIOS battery settings
In BIOS, try changing:
- Battery Charge Configuration → Standard
- Disable any custom charging thresholds or Adaptive charging temporarily
Test with another genuine Dell adapter of the exact required wattage
Even new adapters can be faulty or incompatible.
Boot from Linux live USB
If the issue still occurs outside Windows, that confirms it is not OS-related.

At this point, I would especially suspect:

EC firmware,
charging IC behavior on the motherboard,
or a compatibility issue between the replacement motherboard and battery/adapter.

The fact that charging works normally while powered off is a very important clue.

Vostro

Vostro 3520 shuts down adapter when battery is under 73 %

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