12 volt car battery charger circuit schematic

This battery charger operates by continuously charging at maximum current, gradually tapering off as the battery approaches full voltage. The full load current from the supply transformer and rectifier section is 4.4A. The current decreases to 4A at 13.5V, 3A at 14.0V, 2A at 14.5V, and reaches 0A at 15.0V.

The described battery charger employs a constant current charging method, which is efficient for maintaining battery health and extending lifespan. The charging profile is characterized by a high initial current, allowing for rapid charging during the early stages. As the battery voltage rises, the charger intelligently reduces the current output to prevent overcharging and to ensure the battery reaches a full state of charge without damage.

The transformer and rectifier section, rated at a full load current of 4.4A, is critical in converting the AC mains voltage to a suitable DC voltage for charging. The tapering current values at specified voltage levels indicate the charger’s ability to adapt to the battery's state of charge. At 13.5V, the charger outputs 4A, indicating that the battery is still in the bulk charging phase. As the battery voltage increases to 14.0V, the current tapers to 3A, reflecting the transition into the absorption phase where the charger maintains the voltage while gradually reducing the current.

At 14.5V, the output current further decreases to 2A, signaling that the battery is nearing its full capacity. Finally, at 15.0V, the charger ceases to output current altogether, indicating that the battery is fully charged. This method of charging not only enhances efficiency but also minimizes the risk of overheating and prolongs the overall life of the battery.

Incorporating protection features such as over-voltage and over-current protection circuits would further enhance the reliability of this charger. Additionally, the design could benefit from a microcontroller-based system to monitor the charging process and provide real-time feedback on the battery's status. This would allow for smarter charging profiles and improved user interaction through LED indicators or a digital display.Unlike many units, this battery charger continuously charges at maximum current, tapering off only near full battery voltage. In this unit, the full load current of the supply transformer/rectifier section was 4.4A. It tapers off to 4A at 13.5V, 3A at 14.0V, 2A at 14.5V and 0A at 15.0V.. 🔗 External reference