The electric potential is defined as the work done to bring a unit positive charge from infinity to some point in the field.
We always determine the potential with respect to some reference point. Let the potential at A be zero. If the potential at B is V, then work done to bring charge q from A to B = qV
which is the electric potential energy.
If instead we use some charge Q, the electric potential <em>energy</em> will be QV, but the electric potential will always be V.
