I recently purchased a new wall charger since my other one stopped working and it worked fine for a few days and now it barely works. When I first plug it into the wall socket and then into my phone, it charges for about a minute then it stops charging. But when I connect my phone to my car charger it works fine. What could possibly be the problem? Did I just purchase a defective wall charger? And if so, why would it charge for the minute when it is plugged into a new wall socket? Thanks for feedback!