This chapter is about the special needs of ‘larger’ or ‘specialized’ PV systems for applications in off-grid areas. For skilled engineers or electricians, installing small PV systems is a straightforward process, as energy flows are small, the number of components are few and the design principles are simple. However, when designing and installing larger systems, other factors come into play. Arranging and sizing many modules and batteries requires experience, design skills and installation skills. Control systems are more sophisticated and they should also tell the user more about the status of the system. Different power sources such as diesel generators and wind generators may be incorporated in the system. Because of potentially dangerous voltages and currents, large systems must be designed to strict safety-standards codes. This chapter contains four annotated case studies of solar PV systems that may help designers plan systems.