note: this is MCU controlled at 3.3V, the controller is for both a single 12v gel battery or 1x 24V or 2x 12V gel batteries for 24V, the charge amps should not exceed 1A to the batteries, the input voltage is DC on the pin connector and can be 13.8V or 27.4V DC... (Budget: $10 - $30 USD, Jobs: Circuit Design, Electrical Engineering, Electronics, Microcontroller)