iPhone charger extremely slow after using android USB
So I have an iPhone 5 and I have always used the power adapter and USB that came with the phone. A couple of days ago I used the iphone white power adapter to charge an android phone I have. That is, I used the android USB charger cable with the iphone adapter. Ever since that, my iphone charges extremely slowly with the power adapter. The USB cable itself is absolutely fine, meaning that when I charge my phone using the cable and my macbook, it's like normal, its just the adapter that is frustratingly slow. By slow I mean like 1% charge in 2 hours. Does anyone know why this is? Is there anyway I can "recalibrate" or "reset" the power adapter?
iPhone 5, iOS 6.1.3