An automotive or other power system including a flow cell, in which the stack that provides power is readily isolated from the storage vessels holding the cathode slurry and anode slurry (alternatively called “fuel”) is described. A method of use is also provided, in which the “fuel” tanks are removable and are separately charged in a charging station, and the charged fuel, plus tanks, are placed back in the vehicle or other power system, allowing fast refueling. The technology also provides a charging system in which discharged fuel is charged. The charged fuel can be placed into storage tanks at the power source or returned to the vehicle. In some embodiments, the charged fuel in the storage tanks can be used at a later date. The charged fuel can be transported or stored for use in a different place or time.