XPS 15 9550, random sudden turn-off when running on battery, ASF2 Force Off

Hello Dell Community, My Dell XPS 15 (9550) was experiencing random sudden shutdown in the past months and years when running on battery. BIOS Power Event logs shows ASF2 Force Off. I already have checked the internet and the dell community forums for possible solutions but I didn't found the solution. I have also performed some troubleshooting trying fixing the issue but no success. Based on my research this issue is common to Dell XPS series laptop and also possibly affecting other laptop series such as Dell Precision, Inspiron, and Latitude Series.

In this post, I will describe my experience, troubleshooting performed, and result of my research, and propose a possible solution to Dell to help us fix this issue.

Description:
The problem started a few years back, probably 2018 or 2019 when my original battery (56 wh) is performing poorly after using it for few months. I have experienced random shutdowns when running on battery and the system doesn't recognized the correct capacity of the battery. My laptop can be used longer when it is already at 1-15% charged while at 16-100% it drains faster. I have assumed that the problem is with the battery so I bought (6-7 months ago) a new battery with the higher capacity to replace the old one. After replacing the battery the issue still persists. When the sudden turn off happens, I cannot turn on the laptop when it's not connected to the charger. When I go to the BIOS and check the Power Event logs, I've found the log/error "Power Off - ASF2 force off". I've also tried checking the internet for possible solutions and also performed some troubleshooting to fix the problem but I didn't found the solution.

Performed Troubleshooting:
In trying to solve the issue, I have performed some troubleshooting to fix the problem. The troubleshooting that was performed are the following.

1. Performed Battery Calibration based on this (link1) and this one (link2)
2. Performed both Dell SupportAssist Full Hardware Scan and Enhanced Pre-Boot System Assessment (ePSA) (basic and extended mode) with all tests passed (on-charger or on-battery) and result says the battery is in excellent condition.
3. Performed new Battery force re-detection using this guide. (link)
4. Tried running the system in Windows 10 Safe Mode (Issue still persists when in safe mode).
5. Tried to install other Linux based operating system (i.e. Ubuntu) to check if the issue also occurs in the other platforms but still, it also occurs in other platform.
6. Cleaned the system board, re-seated RAM and SSD, cleaned the fans, and reapplied thermal paste.
7. Reinstalled the Operating System (Windows 10 Home SL) several times and with the latest drivers, software, and OS updates installed. I've also updated firmware and BIOS (tried different versions and loading/restoring BIOS to factory default settings).

Observations after some troubleshooting:
After performing multiple troubleshooting mentioned above the problem still persists. But I've found out that after updating the BIOS to the latest BIOS update (1.13.1) released last Jan 06, 2020 and after cleaning the laptop fans, the frequency of the issue was reduced. Previously, even during the initial startup (after windows login) the laptop suddenly turns-off (improperly). But now it happens less frequent than before. But still, the issue still randomly occurring.

After my latest observations, I'm so desperate in identifying the issue and fixing it. So i tried to perform a System Stability Test using AIDA64 Extreme (v6.20.5300) to check if it can trigger the sudden shutdown. I have performed it both when running on charger or on battery. When I ran it with the charger is plugged, my laptop rarely or doesn't thermal throttle. It also stays at safe temperature (around 75-82°C). It ran it for 6 hours without any issues.

But after performing System Stability Test on battery, the problem occur after few seconds or minutes only. I thought initially that this is caused by overheating; but after checking AIDA64's result after the sudden turn-offs I've found out that the laptop didn't thermal throttle and overheat, and it turns-off even at 48°C and 60°C. It looks like the system doesn't properly handle sudden increase in workload when running on battery. I've tested it on both with my old and new battery, still the same issue occurs. Below are the test setting which triggered the sudden turn-off.

System Stability Test configuration:
Stress CPU - enabled
Stress FPU - enabled
Stress cache - enabled
Stress system memory - enabled
Stress local disks - disabled
Stress GPU(s) - enabled
Duration - few seconds or minutes
Running on battery

I've also performed some research about the ASF2 force off error and its connection to it occurring when running on battery. After my research, I've found out that similar issue also exists in other laptops mentioned below.

AFS2 force off on battery related issue - possible affected systems found in Dell Community Forum:

1. Dell XPS 15 9550 (link1, link2)
2. Dell XPS 15 9575 (link1, link2)
3. Dell XPS 13 9360 (link1, link2, link3, link4, link5)
4. Dell Precision 15 5510 (link1)
5. Dell Precision 3510 (link1)
6. Dell Precision M6700 (link1)
7. Dell Gaming Laptop Series 7000 (link1)
8. Dell Inspiron 15 7567 (link1)
9. Dell Inspiron 15 7570 (link1)
10. Dell Latitude E5430 (link1)

After browsing the internet and reading related issues, there is no found definitive solution to this problem. It also looks like this issue is not unique to my laptop only nor to this specific model (XPS 15 9550). Based on my readings, I've identified some possible causes of this problem.

Theories/Possible Causes:

• Power Management unable to handle sudden increase of workload based on the AIDA64 test as mentioned above.
• Possible issue on Dell's Power Management Algorithm when on battery (old or new) which triggers the ASF2 Force off.
• Power Management conflict after replacing the battery
• Doesn't properly detect/recognize newly installed lower/higher capacity 56whr, 84whr or 97whr battery (detects only the old battery's condition) and causes conflict
• Other issues that only the BIOS developer can identify and fix. It looks like this issue can only be fixed by a BIOS update.

A lot of people are having this issue and are disappointed not having this fixed till this day. This is not an isolated issue but also affects their multiple Dell laptop products. I hope dell will take this issue seriously and give their best efforts in releasing a BIOS update to fix this issue. They can improve what they have done to the Dell XPS 15 9550 1.13.1 BIOS update to make the laptop usable and stable.

I have put so much effort in diagnosing and trying to solve this problem. I hope my efforts won't go to waste and Dell would hear me out and take action to this problem. 

Fixing this issue will not only make their customer happy but will also save them costs in repairs and replacements due to the same reported issues.