Building rural energy infrastructure in developing countries remains a significant financial, policy and technological challenge. The growth of the electric vehicle (EV) industry will rapidly expand the resource of partially degraded, 'retired', but still usable batteries in 2016 and beyond. These batteries can become the storage hubs for community-scale grids in the developing world. We model the resource and performance potential and the technological and economic aspects of the utilization of retired EV batteries in rural and decentralized mini- and micro-grids. We develop and explore four economic scenarios across three battery chemistries to examine the impacts on transport and recycling logistics. We find that EVs sold through 2020 will produce 120-549 GWh in retired storage potential by 2028. Outlining two use scenarios for decentralized systems, we discuss the possible impacts on global electrification rates. We find that used EV batteries can provide a cost-effective and lower environmental impact alternative to existing lead-acid storage systems in these applications.