The new battery not resolving the charging issue suggests the problem might lie elsewhere. Here are some steps to try:

1. Reset Power Connections:

   • Disconnect the power adapter and remove the battery (if possible for your XPS model).
   • Hold down the power button for 30 seconds to discharge residual power.
   • Reconnect the power adapter and put the battery back in (if applicable).
   • Try turning on the laptop.

2. Check the Power Adapter:

   • Ensure the power adapter is firmly plugged into both the outlet and the laptop.
   • If possible, try using a different Dell power adapter compatible with your XPS 15 9500 to see if it charges.

3. Update BIOS:

   • Visit the Dell website and download the latest BIOS update for your XPS 15 9500 model.
   • Update the BIOS following the instructions provided by Dell. Outdated BIOS can sometimes cause charging issues.

4. Hardware Diagnosis:

   • If the above steps don't work, the problem might be hardware-related (e.g., charging port, internal components).
   • Consider contacting Dell support for further diagnosis and potential repairs.

Additional Tips:

• Look for any recent Windows updates or software installations that might be causing conflicts.
• Check Dell's support website for troubleshooting guides specific to the XPS 15 9500 charging issues.

I have tried everything to fix it and nothing permanently fixes this known hardware issue. I paid $3000+ for this laptop and now it is useless. Dell, never again!

@ava10​ Thanks Ava10. I have a second laptop and it had strange issues XPS13 and I update the BIOS and it made a complete mess of the machine. I'm nervous of that.

It just makes no sense to me that the machine can both work and not work properly in terms of charging depending on how it shuts off.

That seems more like a software issue than a hardware one.

I'm not a bit fan of USB-C ports - I think its a weak design easily broken. They seem to be in working condition on this laptop.

I can see why people just pay extra and get an Apple - it works with far less issues.

I'm about 20 years buying Dells and everyone of them let me down eventually. 

@uguryilmaz​ Thanks - yes it seems to be at less not uncommon or rare. I see many posts on similar issues with not actual answers directly addressing it. 

I can charge the battery on this laptop by taking certain steps. If I don't - it won't.

This is rubbish really. It can't simutaneously be working properly and not. That's just bad engineering or software. 

I understand why people just say pay the extra and buy an Apple - Far less issues.

I encountered such problem for the whole year.

Once your machine have the following symptoms, it is related to the WiFi chip firmware issue against Dell's ACPI parameter inside the BIOS, probably Qualcomm Killer QCA6390 (branded as AX500S), not Intel Killer edition.
1. Machines wake up after S3 / suspend, no matter it is triggered by Windows timer or user operations.
2. Machines is idle too long and the WIFI tries to draw huge power suddenly.

You will see an error log inside BIOS stating "Power Off - ASF2 force off". Then, the power led blinks with error color code (orange) and the mainboard refuses to charge the battery from AC adapter. I have seen many cases of replacing big battery, AC adapter, same Qualcomm edition mainboard and no improvement.

It is neither the big battery, CMOS cell (no such thing on 9500), nor AC adapter problem, nor overheat. Don't be mislead. How come a cool wake up machine got heat?  If you play 3D games and the keyboard is hot, such problem disappear. This power failure is caused by WIFI setting in BIOS ACPI table.

You guys may see a yellow exclamation mark on Windows battery and BIOS Diag said no charger is detected. It is because the system board blocks the charging once she thinks there is a power problem.

How to make the battery charge again?Unplug the AC adapter, boot Windows with battery only. Then the power failure lock mechanism will be cleared on the mainboard. Then you can plug the AC adapter again and do charging. However, power management problem will occur again some time later.

I asked Dell Support to fix it many times but they rejected my requests.  They want me to prove and provide solution to them, work at free. Very non-sense.
The recent revision of BIOS like v1.31 make the problem worse, more frequent. They tried to change some setting but in vain.

You have three choices to workaround.
1. Ask Dell to replace mainboard with an Intel Killer edition. The Intel one is newer because Intel acquired Killer that year and no more Qualcomm chip is purchased, resulting in bad support.

2. Disable Qualcomm WiFi inside BIOS, but not Qualcomm Bluetooth. Such device IRQ does not exist and then Windows won't bother it. It is transparent to Windows. (Although Bluetooth and WiFi are on the same QCA6390 chip, they are in different bus type control interface. The BT part has no problem in ACPI table). The, you have to buy a stand alone USB WiFi instead :(

3.Keep pushing Dell to fix it. Eliminate the source of generating wrong power management signals. Actually, I have asked Qualcomm before. She said she has delivered firmware updates to vendor customers regularly (DELL) but Dell refused to adopt / release. The story becomes much more complicated now since Intel bought the whole Killer and made her as a child department.

P.S. This Qualcomm WIFI power management issue doe not only occur on XPS 15 9500, all XPS series with such design also suffer. Similar power management issue is also happened on Asus laptops but her victim is Mediatek WIFI chips. (Yes, Asus finally fixed it by effort in BIOS/firmware)

@Morgan Wong​ Hi,
i've tried with your solution but unfortunately it still not working. I've disabled wifi from bios, and i've used the laptop with a usb-wifi, but i'm still having same trouble. Power charge problems (sometimes it charge, sometimes don't) and randomly reboot. Another issue is that sometimes, when I turn off the PC, it restarts instead of shutting down.

The laptop is practically unusable, and it's crazy to think that it's a €3000 PC.

@Morgan Wong​ This is absolutely true with respect to what you said with the whole rebooting the machine. It works and then again after sometime, it disables. I guess the only work around is that, and perhaps turning off killer options in startup. Also, probably another option is to turn off wifi whenever not using the laptop. Pain in the neck. So much for a costly laptop and bad support.

Dell has chosen to give up on consumers still facing this well-documented issue. 

Yeah this problem will affect most 9500s eventually.  Replacing the motherboard should fix it, but it will reoccur - it's likely a hardware fault with one of the components in the power subsystem causing a reboot when there is a load spike.  Disabling Turbo Boost helps, but is not really a solution.

This solution from Adorable-Safe-8817  on reddit seems to have worked for me. I'm 12 hours in and able to plug/unplug charger normally https://www.reddit.com/r/DellXPS/comments/1dz7t5k/dell_xps_15_9500_sleepcharging_issue_fixed/

How to do it:

1. Uninstall the battery in Windows device manager.

2. Turn off the computer.

3. Turn on again and boot back into BIOS settings (repeatedly press F2 when booting up)

4. Turn C-states off in the BIOS (in "Performance")

5. Boot back into Windows.