Hi [NAME] welcome to this free user to user Alienware laptop discussion forum. This is not Dell Support.  Please run the windows Reliability Monitor and wait for event timeline to load. How to use Windows Reliability Monitor to identify software issues | Dell US Look at recent events to see if this problem is being reported. 
Recently my Alienware 17 R5 (Core i9 8950HK, GTX 1080) when running on battery only, screen flickers, and often hangs and restarts on its own.  This does not happen when using the charger.  I put the battery in an Alienware 17 R4 and it worked perfectly. I also changed another battery the situation is still the same.  This is not a battery fault, but a hardware related problem.  I have reinstalled Windows 10 many times and it will still fail as described above.  Is it the fault of the Nvidia GTX 1080 card? But it's confusing that it doesn't fail when used with the power supply. Appreciate any help, thanks !
17 R5, screen flickers, auto restart, on battery only