Determination of the failure mechanism of stand alone solar street light

Despite the acclaimed long-term benefits of solar PV systems, most stand-alone solar projects in Nigeria seem to fail within a short duration. In this work, an analysis is carried out to examine the factors that lead to such poor performance of solar projects in Nigeria. A case study of standalone solar street lights (SASSL) in Nsukka geographical region in Nigeria was explored. The field work was carried out from Dec 2016 - January 2018. Data from field indicate that in most cases, premature battery failure due to undercharging was responsible for the collapse of these stand-alone solar systems. Given that the PV module is the sole charge generator in SASSL, the energy yield of the PV modules used in the SASSLs were further investigated. Controlled experiments were carried out to determine the impact of specific environmental and installations conditions on the yield of the PV modules. The results of the experiments led to the development of a model. The weather and installation specific data were then inserted into the model and were used to determine the likely reasons for the premature failure of SASSLs. The results indicated that the within the period under review, the PV modules were capable of providing adequate energy to the battery for only 25% of the time. For another 25% of the time the energy provided were marginal while for 50% of the time the energy provided were grossly inadequate. Keywords: Failure, Battery, Dust, Solar, mechanism, Street light, Irradiance, PV Module.