Bangladesh faces significant energy challenges, including frequent power outages that disrupt the operation of over 1 million electric three-wheelers (e-rickshaws) dependent on grid electricity. This study explores the integration of a 400 W monocrystalline solar panel onto the roof of an electric three-wheeler to reduce grid reliance, address environmental concerns, and check the effectiveness of solar panel integration. This study provides an optimistic result for the system with an average solar energy contribution of 13.5%, extending battery lifespan by maintaining a low depth of discharge (DOD), which increases battery life. On average, the system saves 764 Wh of energy daily, reducing CO₂ emissions by 0.382 kg/day and mitigating lead pollution through fewer battery replacement cycles. These improvements lower operational costs for electric three-wheeler owners, enhance energy efficiency, and contribute to a cleaner environment.