This Patriot fence charger powers up to 10 miles (40 acres) of live wire. Suited to use in strip grazing or protecting remote areas where regular access is inconvenient. The SG150 can help protect erosion areas from further stock damage or prevent livestock from damaging young trees or riverbanks. It has a 5W solar panel and 6v battery included. This unit can operate up to 21 days without sunlight. Three year warranty applies. Up to .15 joules maximum energy output, .21 joules stored output.