Pinch Analysis has been recently extended into the design of hybrid power systems to determine the maximum power recovery and battery storage capacity. Graphical and numerical Power Pinch Analysis (PoPA) tools are systematic and simple to implement in the optimisation of power systems. The losses incurred in the systems however are not taken into consideration in the previous works. This paper extends the PoPA method by considering the energy losses that occur in the power system conversion, transfer and storage. These losses on the minimum outsourced electrical energy targets and storage capacity are evaluated and the Storage Cascade Table (SCT) of PoPA is developed to include the effect of energy losses in the system design. The developed method is demonstrated on an illustrative case study and reflects the actual power targets for off-grid hybrid power systems.