The GR440 incorporates the latest MPPT algorithm technology and is capable of up to 40A input (600W @ 12V / 1200W @ 24V). MPPT is the best way to maximize the efficiency of your solar array. Especially critical in cloudy areas, MPPT technology adjusts the power and current of your solar panels to maximize the output. This means more watt-hours into your batteries in a given amount of time, compared to PWM or on-off charge controllers. If you want the latest and greatest, best efficiency and Bluetooth monitoring capability, this charge controller is exactly what you're looking for. Features Intelligent MPPT algorithms pull as much power as possible from your solar panel(s). Excellent thermal performance with a heavy aluminum heat sink to dissipate heat for longer product lifetime. Conformal coated to protect against humidity and moisture. Back-lit glass touch screen is simple and intuitive, and easy to see in the dark. All-new updated Bluetooth app, "Charge2.0" supports power generated logging for up to 300 days. Includes external temperature sensor to protect your batteries from being damaged from fast charging at high temperatures. Programming and setting adjustment can be made via Bluetooth: Specifications Part Number GR440 System Voltage 12V DC or 24V DC Charge Method MPPT Battery Compatibility Lithium Iron Phosphate (LiFePO4) 3S Lithium (12V) / 7S Lithium (24V) Lead Acid (Deep Cycle / Flooded / Sealed) AGM / Gel Max Solar Panel Input VOC 100V DC Max Max Solar Panel Input Power 600W/12V; 1200W/24V Rated Charging Current 40A Protections Conformal coating for humidity protection, PV and battery reverse polarity protection, 125% overcurrent buffer protection Max Ambient Operating Temperature -35C to +45C Weight 4.8 lb Dimensions 8-5/8" x 6" x 2-9/16"