Decentralized solar photovoltaic (PV) systems have emerged as an option in unelectrified rural areas for clean lighting and reduced kerosene use. Despite benefits, there are significant barriers to implement and sustain solar PV systems because of inadequate understanding of the feedback between adoption, diffusion, and implementation processes in resource poor communities of low and middle income countries. We analyze the social-behavioral and solar lamp assembly and distribution processes involved in implementing a million solar lamps in rural India and present a novel system dynamics framework to understand solar lamp technology implementation in India and other countries of South Asia. Our framework of three inter-locked subsystems – Localization, Affordability, and Saturation – explains how localization, affordability, and saturation emerge from a structure of feedback mechanisms and interact to drive adoption and sustained use of solar PV systems in resource poor communities. A system dynamics approach highlights the importance of understanding feedback and interdependence of these factors, provides tangible insights for future decentralized solar lamp and solar home product deployments.