This series solar charge controller is a kind of intelligent, multi-functional solar charge and discharge controller. All the controlling parameters can be reset flexibly to satisfy your different needs.   Features: Visual LCD graphic symbol, brief key operation.  Automatic identification system voltage level, intelligent PWM charge mode.  Adjustable charge/discharge control parameters, settable operating modes of loads.  Multiple selection of battery.  Adds current display function.  Battery over temperature protection, low voltage/reverse polarity protection.  Over-load and short-circuit protection.  With dual USB 5V output.   Specifications: Color: Black + Blue;  Material: Plastic;  Rated Voltage: 12V / 24V (Auto Switch);  Max. Charge/Discharge Current: 10A / 20A (Optional);  Max. Solar Panel Input Voltage: ≤50V;  Stop Charge Voltage: 14.7V/29.4V;  Low Voltage Recovery: 12.2V/24.4V;  Low Voltage Protection: 10.5V/21.0V;  USB Output Voltage/Current: 5V 2A;  No Load Loss: ≤10mA;  Temperature Compensation: -3mV/Cell/°C;  Operation Temperature: -20°C~60°C;  Item Size: 13 * 6.8 * 3.2cm / 5.12 * 2.67 * 1.26in;  Item Weight: 119g~152g / 4.21oz~5.38oz;  Package Size: 14 * 8 * 4cm / 5.51 * 3.15 * 1.57in;  Package Weight: 154g~187g / 5.46oz~6.61oz;   Note: 1. Order of Connection: connect storage battery firstly, then connect the solar panel; Order of Disconnection: disconnect the solar panel firstly, then the storage battery; otherwise it will cause damage to the controller.  2. The inverter can't be connected to the controller directly.  3. The controller will generate heat during operation, please notice that put the controller on flat surface with good ventilation.   Configuration Selection: For 12V System, battery voltage is 12V, recommended input voltage of solar panel: 16-22V, when actual input voltage>50V, controller will be damaged;  For 24V System, battery voltage is 24V, recommended input voltage of solar panel: 32-44V, when actual input voltage>50V, controller will be damaged.   Package List: 1 * Solar Charge Controller;  1 * User Manual (English)