Solar lights are powered by batteries. You’ll quickly realize why this is critical.
The tiny yet efficient panel on top of the solar light charges the battery throughout the day, and then the light draws its power from the battery during the night.
Are you getting it? Because here is where the intellectual jump occurs.
Solar powered street lights endure in theory indefinitely; what they do not last indefinitely are the batteries contained therein. After a few charge-discharge cycles, batteries degrade, and after three to five years, you’ll likely find the light is weaker than it was. I’m sure you were previously aware of all of this. What you may not know is that LED bulbs last 20+ years and can always be replaced. Finally, the top-mounted solar panel will progressively lose efficiency over the next 15–20 years. After 15 years, it may be just 80 percent as efficient as when you purchased it.

That is rather excellent! What’s more, battery, lighting, and solar technologies are all advancing at an exponential rate. Thus, the next time you replace your batteries in five years, you may get a new battery that lasts between ten and thirty years. Keep in mind that batteries should be disposed of responsibly. We really do not need such substances to be disposed of in a landfill.