How long does the battery of an outdoor waterproof solar street light last?

Key Factors Affecting Battery Lifespan

1. Battery Type: This is the most critical factor.
   • Lithium-ion batteries (e.g., LiFePO₄): The most common type in modern solar street lights, with a lifespan of 5–8 years and over 2000 charge-discharge cycles. They perform well in temperature extremes (-20°C to 60°C) and have low self-discharge.
   • Lead-acid batteries (e.g., gel, AGM): Older technology with a shorter lifespan of 3–5 years and around 500–1000 cycles. They are bulkier, more sensitive to high/low temperatures, and require occasional maintenance (e.g., checking electrolyte for non-sealed types).
2. Usage and Environmental Conditions:
   • Temperature: Extreme heat (above 40°C) accelerates battery aging, while extreme cold (below -10°C) reduces capacity temporarily. Waterproof designs protect against rain but not temperature damage.
   • Charge-Discharge Cycles: Frequent deep discharges (e.g., using 80%+ of battery capacity nightly) shorten lifespan. Intelligent controllers that limit deep discharge (to 50–70%) extend battery life.
   • Sunlight Availability: Insufficient sunlight (e.g., long rainy seasons, shaded areas) leads to incomplete charging, which causes "sulfation" in lead-acid batteries or irreversible damage to lithium-ion batteries over time.
3. Controller and Maintenance:
   • A quality charge-discharge controller prevents overcharging (which overheats batteries) and over-discharging (which strains battery cells), adding 1–2 years to lifespan.
   • Regular maintenance (e.g., cleaning battery terminals, ensuring waterproof seals are intact) avoids corrosion or water damage, especially for lead-acid batteries.

Tips to Extend Battery Lifespan

• Choose solar street lights with lithium-ion batteries (LiFePO₄) for longer durability, especially in harsh climates.
• Ensure the solar panel is installed in a location with 6+ hours of direct sunlight daily to avoid incomplete charging.
• Select products with an intelligent controller that has overcharge/over-discharge protection and temperature compensation.