Solar Charge Controller for managing battery charging which helps to increase a batteries lifetime by preventing overcharging. Batteries must be 12V or 24V. Controller does not charge a 12V and 24V battery. Built in Industrial Microcontroller. State of charge (SOC) showing battery condition. Pulse Width Modulation with four stages of charging. Short circuit, Reverse current, Reverse polarity, Overcharge protection. Fine workmanship and good performance. Easy to use. Long service life. Current: 10A / 20A / 30A System voltage: 12V/24V adaptive Maximum photovoltaic voltage: 41V Voltage drop of charging circuit: Less than 0.2V Boost charging voltage: 14.6V (only for 12V system, if using 24V system, please x2) Direct charging voltage: 14.5V (only for 12V system, if using 24V system, please x2) Constant voltage charging voltage: 14.2V (only for 12V system, if using 24V system, please x2) Float voltage: 13.8V (only for 12V system, if using 24V system, please x2) Charging recovery voltage: 13.0V (only for 12V system, if using 24V system, please x2) Adjustment method: PWM Standby current:Less than 10mA Temperature Compensation: N/C Working temperature: -35~+60 Colour:As Shown Material:plastic Package Contents: 1 x Solar Charge Controller Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.