Systems and methods for completely filling a storage vessel with a fuel gas. One method includes flowing the fuel gas along a fluid conduit in fluid communication with the storage vessel and actuating a valve disposed along the fluid conduit to provide a predetermined difference between the pressure of the fuel gas upstream of the valve and the pressure of the fuel gas downstream of the control valve. The predetermined difference is selected such that the temperature of the fuel gas is reduced to a predetermined temperature after passing through the valve. The method further includes dispensing the fuel gas into the storage vessel at a first mass flow rate.