Asus ROG G751JL WH71(WX)
Operated normally since purchase, 2015 December (build date: Oct 2015).

ISSUE: SUDDEN SELF-POWER-DOWN (FOLLOWING POWER-UP, LOG IN, COMPLETE BOOT CYCLE: SUDDEN SELF-POWER-DOWN)

Approximately 10-days before this issue, the battery of the G751JL seemed to lose the ability to charge or hold charge - or that ability was greatly diminished.

The G751JL has OEM-installed RAM only (no add-on RAM); HDD replaced at purchase with 2ea Samsung Pro SSD - operated as a Mirror using Windows 10 "Storage Spaces." This laptop has operated with no issues since 20 December 2016 - until this self-power-down issue.

State 1: Cold Power Up w/Log-In/Boot Cycle.
G751JL power-available LED illuminated; push Power Button - it seems to allow normal power-up; allows Log In and runs Boot Cycle; Task Bar shows A/C Power - but battery show 0%, and not charging; allow beginning of Tasks - but but self-powers-down (turns-off) with no warning approximately 3-minutes after power ON.

After self-power-down, it will immediately allow a repeat starting with Log-In, which replicates all the same stages until self-power-down.

This whole cycle replicates identically every log-in.

State 2: Cold Power Up: NO Log-In Attempt
G751JL power-available LED illuminated; push Power Button, but NO Log-In Attempt;
pre-Log-In photo appears on Desktop; G751JL remains ON - touch keyboard/mousepad and Desktop pre-Log-In photos restores to Desktop; G751JL remains ON for many minutes before self-powering off; upon self power-off, G751JL power-available LED remains illuminated. IE: power remains ON much longer when no Log-In attempt is made.

We also own a 5-year-old G75VW, which is operating normally after 5-years.

This G751JL is 21-months old, and is very important in our household -
any suggestions anyone might have will be greatly appreciated.

Also: plan to order a replacement battery - will plan to get an OEM Asus, unless anyone can recommend an excellent (ie: better) after-market battery.

Thank you so much!

Kristen / Houston