I usually use the laptop with the power adapter plugged in so i just noticed this problem. The laptop is on Windows 10 Home 1709 16299.248, 6th Gen Intel. Recently when using the laptop just on its battery i noticed that it suddenly powered down without warning as if the battery was pulled out, so there was no proper windows shutdown. Testing it several times showed that the battery would die around 30-40% on the window's battery indicator. Looking at sources online said that it could be a battery calibration issue but I've been letting the laptop run on battery till it dies on its own but there's no change in the battery estimate for this 'calibration routine'.
How could i fix this issue or could it a battery hardware problem?