My wife got her Samsung Galaxy S3 back in June and has been happily using it since. Few days ago I noticed her S3 stopped charging when plugged into the Samsung original AC power plug. After a whole night charging the battery remained the same as before plugged into the charger.
Weird thing was that when using the car charger or my HTC charger, the S3 charged properly. So, you would guess that the S3 charger was bad. STOP! When I used the S3 charger to charge my HTC Desire S it charged nicely.
WAIT WAIT WAIT!!! What was going on??? The S3 charged nicely using other chargers. The S3 charger charged my HTC phone nicely.
Hmmmm!!! After Googling around, I found out this was a known bug for S3. Not sure whether it was hardware or software related.
SOLUTION: connect your S3 to any PC or laptop using the USB cable of the S3 power plug. Let it charge for few minutes. Now plug the S3 and the USB cable back to the AC charger. PROBLEM SOLVED!
I just did this half an hour ago before I write this blog. The S3 battery level is nicely coming up from 61% to 74% since plugged into the AC plug.