Modern light-emitting diode (LED) technology holds great promise for remote or stand-alone photovoltaic (PV) lighting applications. Acceptable intensities can be obtained for a fraction of the energy consumed by incandescent or fluorescent lighting, resulting in smaller and less costly PV/battery systems. Applying PV technology to solid-state applications seems straightforward at first glance. Yet, all too often, PV-powered products fall short of expectations. There can be many reasons for failure. As often as not, we find that failure results from misunderstanding or ignoring well-established principles of PV system design, or by assuming maintenance is unnecessary because of PV's apparent simplicity. Most of these fatal errors have simple and easily applied solutions. The most common fatal errors are discussed, and approaches are recommended that can help ensure a successfully operating system. The methodology described below is applicable to all sizes of PV power systems, ranging from one needed for a single LED to one capable of supplying many kilowatts.