The Bioenno Power SC-1220JU 12V, 20A Solar Charge Controller is an advanced intelligent multi-stage MPPT solar charge controller featuring our proprietary CC/CV (Constant Current/Constant Voltage) technology designed specifically for LiFePO4 (lithium iron phosphate) batteries. Designed for 12V systems and handling up to 20A, the controller uses a Buck Conversion Circuit and further uses an MCU to adjust the solar panel to a working point in order to make the solar panels output maximum power. When the working point of the solar panels deviate from the maximum power point, the MCU will adjust the solar panels working point based on an MPPT calculation to make the solar panels provide their maximum power point. Compared with PWM controllers, this MPPT controller can increase the output power of the solar panels by 5% ~ 30%. The output power increases proportionally by various factors, such as the solar panel properties, light intensity, and humidity. This solar controller is intended for 12V LiFePO4 Batteries Only. Please note that for any solar setup in which you are using a panel in conjunction with a battery and/or a load a solar charge controller is absolutely necessary. DO NOT plug a panel directly into your battery or your load! OPERATION Mount the controller on the wall and fasten the screws. Check whether the battery voltage and solar panel array voltage is within the requested range. Connect the battery to the controller Connect the load to the load terminal Connect the solar panel array to the input of the solar controller To switch the load on, hold the button for 3 seconds. To switch the load off, hold the button for 3 seconds.