Feature:1. 1A 3.2-18.5V multi-function battery charger with photovoltaic cell MPPT function.2. Complete charging controller for single or multiple Li-ion, LiFePO4 or lithium titanate batteries.3. The maximum load current / output current is 1A, but you can change the current by changing the value of the Rcs resistor.4. Can be used as voltage source when battery is absent.5. Automatic conditioning of deeply discharged batteries.6. Automatic recharge, battery overvoltage protection.Specification:Item Type: Solar Panel MPPT Controller Charging ModuleOption: 9V, 18V9V (for 9V Solar Panel): Input DC 9-28V, Output DC 1.2-8V Adjustable (3.6V 4.2V 4.3V 4.35V 7.2V) 18V (for 18V Solar Panel): Input DC 18-28V, Output DC 1.2-17V Adjustable (3.6V 4.2V 4.3V 4.35V 8.4V 12.6V 16.8V)MPPT Disable (Change R5 to 12KΩ, it is recommended to buy DD28CRTA): Input DC 7-28V, Output DC 1.2-21V Adjustable(3.6V 4.2V 4.3V 4.35V 8.4V 12.6V 16.8V 21V)LED indicator: ''CR'' LED is charge status indicatorOperating Ambient Temperature: -40℃ to ＋85℃Package List:1 x Solar Panel MPPT Controller Charging Module