Acer A715-76G Fan running after shutdown

I purchase Acer A715-76G 2 years ago. Since last 6 months I was noticed that my laptop battery is auto discharged but some days ago I saw that after shutting down the laptop one of two fans are running permanently and that is the main reason of battery discharge. I have tried all the method like battery resetting through pinhole. off quick boot mode and everything but nothing can solve my problem. When I keep pressing the battery reset button fan stops for the time and as soon as I release it start running. What is the main reason of this. I searched on the google and I saw the many Acer laptop has the same issue. May be a manufature defects or they may be planned it for battery to auto degrade the health so we need to install a new one. My battery is completed 72 cycles cause of auto discharged by fan. I never used my laptop on battery. Running fan discharge the battery in 24-30 hours completely.