Gallagher G341424 Solar Fence Energizer, 0.20 JoulesThe S20 portable solar energizer powers up to 12 miles 40 acres of single wire fence with no vegetation and boasts several solar technology improvements that make it ideal for temporary grazing applications, livestock and pet containment. Joules: 0. 20 Continue to work for up to 3 weeks without sun Can be set up easily in any location and moved about as required Comes with a rechargeable battery, solar panel and post mount, as well as fence and ground