solar tech SLS are independent sources of light in remote areas, streets, farmhouses, construction sites, guard locations, parking lots, squares, etc. Throughout the night for safety/security purposes. The energy stored during the day is used during the night. The light automatically switches on at sunset and switches off at sunrise or can be controlled manually as per the model you select.solar SLS consists of the module(s), tubular/SMF battery with battery box, 5mtr pole (4mtr above ground), lamp housed in a weatherproof assembly having a reflector on its back & inbuilt mosfet-based charge controller & inverter.