Asus S551L won't turn on with AC power when internal battery low/caput

[will.o.temp]

The Asus S551L has internal(non-removable) battery. When its battery is low or no charge, even with AC power adapter plug in, It won't turn on or it turn on for few seconds then off itself. I leave it away for 20 mins with AC power and later can turn it on normally. The full battery only last 30 mins. After cleaning the laptop, I gave it back to the owner.

Few days later, the laptop cameback again, now it wont turn on at all. I left it charged for 30mins, 1hrs, 3hrs but not avail, no power LED. I tried it with 2 new power adapter. Iunplugged its internal battery and still won't start. No Power LED.

Have anyone seen laptop on ac power wont start if internal battery caput/disconnected?
Is it 100% battery problem?

 

[webworkings]

Oh yeah. There are many laptops that will not function without a working battery. I would suggest replacing that battery.