Features: This solar charging controllers is suitable for both 12V and 24V power systems. Has advanced maximums power points tracking technology. It continuously tracks the maximums power points of the array to obtain maximums power to charging the battery. Monitors the charging condition and voltages on the LCD display for improved control. Equipped with necessary protections devices, the control parameters of systems is adjustable, easy to set up and operate. Builted in overheating, overcurrent, short circuits, open circuits protections, controllers automatic recovery. Specifications: Component: Plastic Current: 20A/30amp/40A (optional) 20A/30amp Size: about 12x6.3x17.5cm/4.72x2.48x6.89inch 40A Size: about 13.5x6.5x19cm/5.31x2.56x7.48inch systems voltages: 12/24V automatic Wide voltages Input: 100V Battery voltages ranges: 8-32V 20A supports photovoltaic input power: 390W 12V/780W 24V 30amp supports photovoltaic input power: 390W 12V/780W 24V 40A supports photovoltaic input power: 520W 12V/1040W 24V Package Includes: 1pc Solar charging Controller note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.