In-field assessment of batteries and PV modules in a large photovoltaic rural electrification programme

Assuring the sustainability of quality in photovoltaic rural electrification programmes involves enhancing the reliability of the components of solar home systems as well as the characterization of the overall programme cost structure. Batteries and photovoltaic modules have a great impact on both the reliability and the cost assessment, the battery being the weakest component of the solar home system and consequently the most expensive element of the programme. The photovoltaic module, despite being the most reliable component, has a significant impact cost-wise on the initial investment, even at current market prices. This paper focuses on the in-field testing of both batteries and photovoltaic modules working under real operating conditions within a sample of 41 solar home systems belonging to a large photovoltaic rural electrification programme with more than 13,000 installed photovoltaic systems. Different reliability parameters such as lifetime have been evaluated, taking into account different factors, for example energy consumption rates, or the manufacturing quality of batteries. A degradation model has been proposed relating both loss of capacity and time of operation. The user – solar home system binomial is also analysed in order to understand the meaning of battery lifetime in rural electrification. •A set of 40 batteries has been tested in-the-field from an electrification programme.•After six months the remaining capacity of the batteries is lower than 80%.•The remaining capacity of the battery that leads to user dissatisfaction is 18%.•A set of 41 mono-crystalline modules have also been tested in the field.•The mean power degradation rate of the PV modules is between 0.4 and 1.1% per year.