Usually the solar controller is the short part of solar street light, and battery is the short for small solar lamps4. Housing: depends on the material type. For plastic parts, usually ABS is most suitable for solar light. For Metal parts, #304 stainless steel, #201 stainless steel and aluminum are commonly used3. Battery: it depends on the type, please refer to previous article;2. LED: the norminal life-span of LED is 50,000 hours, but luminous decay is very obvious. SMD LEDs are better and less decay compared with staight pin LED1.Solar panel: usually solar panel can work over 15~25 years although the efficiency will decline as using;Usually the life time of solar lights depends on its main components