Appropriate battery technology for a new, rechargeable, micro-solar lantern

A detailed market survey in Kenya has assessed the performance of currently available domestic lighting systems, for example, kerosene ‘hurricane‘ lamps and (generally poorly constructed) solar lanterns, against end-user expectations. Following this survey, the UK Governmentʹs Department for International Development approved a project to design and develop an affordable, reliable and efficient solar lantern, which would provide improved lighting to rural households. This paper provides an overview of the end-user requirements, and corresponding lantern design features. The suitability of three commercially available alternative battery technologies, viz., nickel−metal-hydride, nickel−cadmium, and valve-regulated lead−acid (VRLA), for use in this PV application are discussed. Finally, improvements to the VRLA batteries are proposed, which would further enhance their cycle-life and reduce the energy cost per cycle.