Help Charging question for my S3

[mcnn]

Hi. My S3 will not charge with a portable charger, or two car chargers. When I plug the phone in with either method, they don't seem to connect. With the portable charger, I can remove the usb end, and plug it into an ac charger, and it immediately connects. I did this with two different cords. I also plugged both the car and portable chargers into an S4 and it worked perfect.