Photovoltaics (PV) are increasingly important for electrification in rural Sub-Saharan Africa, but what is the best battery technology to use? To explore this question, a small-scale domestic PV system for South Africa (20-year lifetime) to deliver 1.42 kWh electricity from batteries overnight with 10-h discharge was costed with various Li-ion, Pb-acid and Aquion aqueous hybrid ion batteries (AHIBs). Environmental impact; compatibility with circular economy; potential for cost-reduction through lifetime extension; and valorisation of batteries at end-of-life is discussed. Batteries are 81-93% of system costs, and battery production required over the system lifetime would emit 743, 674 and 6060 kg CO2-eq (Pb-acid, Li-ion and AHIBs respectively). Hazardous materials in Li-ion and Pb-acid batteries pose risks at end-of-life. Li-ion and AHIBs face potential resource supply constraints due to use of Co, Li and graphite. Closed-loop recycling and refurbishment of Pb-acid batteries is well established in South Africa. Currently, no African facilities for Li-ion or AHIB recycling exist, with little opportunity to retain material value from these batteries within the region. Despite lower efficiencies and shorter lifetimes, Pb-acid batteries, which are readily available from domestic manufacturing at low cost, are the current best choice for sustainable small-scale domestic PV systems in South Africa. (C) 2018 The Authors. Published by Elsevier Ltd.