HiTec has two (2) x4 chargers. The original x4 and the x4-eighty. So unless the OP comes back and specifically says that he has the eighty, those of that say his charger does not have the power, is the charger we are talking about. You are taking it that he has the x4-eighty and not the x4.
There is no way you are getting 7a charging a 4s with an 80w charger.

X4: http://hitecrcd.com/products/charger...harger/product

X4-eighty: http://hitecrcd.com/products/charger...harger/product