Lead-acid batteries, known for their traditional use in cars, have seen a resurgence due to their low cost, availability, and recent innovations. These batteries are now used for sustainable energy solutions, integrating renewable energy sources, and supporting decentralised power grids. Notable advancements include valve-regulated lead acid batteries, deep-cycle designs, and smart charging methods. They’re used in diverse sectors, such as industrial applications and rural electrification, while researchers strive for further improvements. Despite challenges like limited energy density and safety concerns, they offer cost-effectiveness with a positive return on investment.