Alienware 17 Won't Stay on Mains & Crashing on Battery

Hi,

I have an Alienware 17 with a GTX 860M with Intel Core i7-4910MQ CPU @ 2.90GHz which is now about 3 years old. A little while ago, I needed to replace my battery – initially no problem. About a month ago I noted that on mains, when the laptop battery reached full charge, the laptop would move to battery power instead of remaining on mains (even though it was still plugged in) until the battery percentage dropped to 99%, then it would move back onto charge until it hits 100% before switching back to battery and so on. This has never been something that's happened before, as previously the battery would hit 100% and remain on mains but not charging.

Furthermore when playing games on Steam, the laptop started crashing, as if the switch had been turned off on a desktop computer. Upon further investigation, I realised that the crashing during gaming occurred as the laptop moved off mains charge and onto battery, I also then discovered that booting the laptop on battery produced a similar system crash and afterwards meant couldn't turn the laptop back on without plugging it into the mains.

After any crash, when switching the laptop back on the battery is on 98% or 99% so I know it isn't switching off because the battery is dead.

I've already tried a number of solutions on the laptop itself:

• Reinstalling all drivers
• Updating BIOS
• Completing checks on all internal systems (all of which passed)
• Running anti-virus checks
• Run system file checker
• Changing battery settings to different modes
• Using both on and off for desktop mode
• Battery checks done – it shows no issues

Furthermore I contacted the support team of the game that I happened to be playing during the crashes (2k, Civilization VI) and followed their recommendations for fixing crashes, none of which have rectified the issues but focussed more on the software side of things, including:

• Reinstalling the game
• Reinstalling DirectX
• Checking DxDiag Files
• Clean booted Windows

Game issues were resolved but not the battery / power ones. During the last month of attempting to fix this issue or at least narrow down the root cause, the laptop has also started to crash while just browsing the internet but as before it is only when the laptop battery reaches full capacity and moves onto battery.

Finally I went into the system diagnostics and changed the battery charge limit to 55% to see if the battery would remain on mains but not charging, and exactly like previously the laptop charges up to the new max setting (55%) then just as when it was set at 100% the laptop moves onto battery power until the charge drops to a percent or two then it moves back onto mains until it hits its max setting, before it then goes back onto battery until the charge drops a percent. This switch seems to cause the crashes.

I don't mind having to use the laptop on mains if these crashes occur on battery power (it's not ideal, but it's manageable), but while the laptop won't remain on mains but not charging at full battery percent, it's impossible to play games on and now with the added crashes during internet browsing, it's become too unreliable to perform the simplest of tasks on.

Any help or solution suggestions would be greatly appreciated.

Thanks