The 20 Watt Solar Panel charges the 12-volt gate operator batttery when AC power is not available. The solar panel kit comes with tubular steel support, mounting clips, wire connectors, and 8 ft. of low voltage wire. Installation in some regions require multiple panels for adequate charging power. Wattage necessary depends on the gate opener power needs, additional access controls and devices that draw on the battery, and amount of exposure to sunshine. All DC control boards are pre-wired for the solar panel. Call us 1-800-504-3952 to help determine your solar needs.