This paper presents the design of a 300W charger for lead-acid battery charging applications. It focuses on achieving higher efficiency, increased power and component density, and cost-effectiveness. Resonant converters, particularly those using the LLC half-bridge configuration, are emphasized for their ability to operate at higher switching frequencies while minimizing losses. The charger's unique feature is its fanless design, ensuring compliance with EN60335-1 standards regarding temperature limits on the charger's surface. The paper presents the charger design, resolves surface temperature issues, and shares experimental results demonstrating its performance and temperature control during the lead-acid battery charging process