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.
Our friend and comrade IronFly has reached his 10,000th post to our little Community. During the last 4 years he has helped countless Acer customers providing help, advice and answers. The Acer Community team feels honored to count you as our friend. Thanks IronFly!