ABSTRACT The essential use of 12V lead acid batteries in automobile engines to power incorporated electrical appliances, and also the sudden failure of vehicle charging systems that often give rise to a drain of battery cells has necessitated the construction of battery chargers suitable for fully restoring the lost charge into the required 12V battery cells. Most 12V battery charging devices built for commercial services are usually heavy and bulky and lack a protection circuit and a sensitized control circuit required for automatic deactivation of charging once the battery is fully charged. In this new design product, the size of the battery charger was made portable and light in weight to enable end users to convey it as easily as possible. Short circuits and current reverse protection were incorporated as well. A sensitized control circuit was implemented to ensure that charging is terminated immediately when the battery is fully charged. This is to avoid the possible occurrence of overcharging that may result in loss of electrolytes. In this report the components used to actualize the design work were listed and the design specifications were tabulated with the circuit diagram well detailed. The operational principle of the built charger clearly explains how the design objectives were reached. An adopted formula with example on how to calculate the charging time of a battery when using the product was derived. Design limitations, recommendations, and conclusion were stated. Various relevant tests were conducted with its corresponding results tabulated. Finally, a well labeled image which lays out views of the completely constructed battery charger is attached in order to appreciate the effort and the value of the design work. (Keywords: AC power supply, rectification, charging, deactivation, full charge) Considering, the compact shape of the battery charger, with very low ventilation an extractor fan was incorporated to drive away hot air and moisture that would be generated inside the charger compartment during operation.