When your tablet is off, blow into the charging hole, then use an open safety pin to dislodge any dust or dirt. Then blow again into the hole. Also ensure that the charger is clean. That should take care of your problem.
Member RevoMaxx is quickly moving up the ranks of Acer Community. He joined us in September and is already making a difference. It's great to see new members like him make a difference only after a few months. Thanks RevoMaxx!