The growing integration of batteries in modern applications, ranging from portable electronics to stationary energy storage systems, requires a deeper understanding of degradation mechanisms and the advancement of efficient testing methodologies. This paper presents a battery degradation testing system based on a regenerative architecture, where two batteries are operated concurrently to enable energy exchange between them. This configuration significantly reduces the net power drawn from the external source, leading to lower operational costs and enhanced energy efficiency during testing procedures. The proposed testing platform is implemented using two bidirectional buck-type dc-dc converters operating under current-mode control. System validation is performed through both simulations, carried out in the PLECS environment, and experiments using a prototype composed of two 7 Ah lead-acid batteries. The results demonstrate a substantial reduction in source power demand.