Hi newcomer and welcome to the Tom's hardware forum.
Like I see exist three possibilities for ur problem:
1- The battery is coming to the end of his life.
2- The charger is dead.
3- Both battery and charger are the problem.
How to know what it's?, if u can test with another charger.
We swapped batteries, swapped Power Supplies in combination.
Have a feeling its the Mainboard, actually, STRONG feeling it's the mainboard.