Best Solar Highway Lighting Design Guide

1.Best Highway Solar street Light Design Guide

As a professional manufacturer of solar street lights, we are committed to providing efficient, reliable, and sustainable solar lighting solutions.
This design guide aims to assist EPC contractors in selecting the best configurations for designing solar highway lighting systems, ensuring
system stability under various environmental conditions.

2. System Components

The solar highway lighting system mainly consists of the following components:

• Solar Panels
  • Reason for Selection: The core component; conversion efficiency directly affects system performance and cost. We recommend using high-efficiency monocrystalline solar panels with a conversion efficiency of over 20%.
  • Specific Configuration: Each street light is equipped with a 150Wp monocrystalline solar panel with an output voltage of 24V.
    The number of panels should be arranged reasonably based on road length and sunlight conditions.
  • Installation Angle: Determine the optimal angle based on local latitude to maximize solar energy receive efficiency.
    For example, in Shanghai, the best angle is 31°. Solar Street Light Tilt Angle Installation: A Comprehensive Guide
• Batteries
  • Reason for Selection: A key storage component that needs high capacity and long life. We recommend lithium-ion batteries for their long cycle life and low maintenance costs.
  • Specific Configuration: Each street light is equipped with a 24V/100AH lithium-ion battery, ensuring normal operation during six consecutive days of rainy weather. Solar Street Lights Battery Comprehensive guide
  • Charge and Discharge Management: Use an intelligent charge and discharge controller with multiple protection functions to extend battery life.
• LED Street Lights
  • Reason for Selection: High luminous efficacy, long life, and low maintenance costs.
    We recommend high-efficiency LED lights to ensure illumination effect and energy savings.
  • Specific Configuration: Each street light uses a 100W LED light with a lumen output of 10,000lm,
    color temperature set between 5000K to 6000K, and a color rendering index of at least 80.
  • Fixture Arrangement: Based on road width and lighting needs, arrange pole spacing reasonably. Main roads: 30m, secondary roads: 40m, branch roads: 50m.
• Control System
  • Reason for Selection: The key to ensuring stable system operation. We recommend an intelligent control system to facilitate automated management.
  • Specific Configuration:
    • Time Detection: Automatically adjusts power supply according to time periods.
    • Light Intensity Detection: Monitors battery voltage; charges when the voltage is high and prevents back current when low.
    • Charging Method: Uses different charging strategies based on battery voltage.
    • Under-voltage Protection: Automatically cuts off power and alarms when the battery voltage is insufficient.
    • Remote Monitoring: Allows real-time monitoring of light and battery status via mobile or cloud platforms.

3. Core Lighting Parameter Requirements

• Lumens (lm)：What is Lumens?
  • Main roads: ≥ 10,000lm.
  • Secondary roads: ≥ 7,000lm.
  • Branch roads: ≥ 5,000lm.
  • Interchanges and toll plazas: ≥ 12,000lm.
  • Tunnels: Entry section ≥ 12,000lm, exit section ≥ 10,000lm, middle section ≥ 8,000lm.
• Luminous Efficacy (lm/W):Understanding the Luminous efficacy of Solar Street Lights
  • LED Lights: ≥ 150lm/W.
  • Fluorescent Lights: Approximately 80lm/W.
  • Incandescent Lights: Approximately 20lm/W.
• Uniformity：What is Light Uniformity? How to Calculate Lighting Uniformity
  • Main roads: ≥ 0.4.
  • Secondary roads: ≥ 0.35.
  • Branch roads: ≥ 0.3.
  • Interchanges and toll plazas: ≥ 0.5.
  • Tunnels: Entry section ≥ 0.6, exit section ≥ 0.5, middle section ≥ 0.4.
• Color Temperature (K):Understanding Solar Street Light Color Temperature (CCT): Kelvin
  • Main and secondary roads: Recommended 5000K-6000K.
  • Branch roads: Recommended 4000K-5000K.
  • Tunnel entry and exit sections: Recommended 7000K-8000K.
  • Tunnel middle section: Recommended 5000K-6000K.
• Color Rendering Index (CRI)：Color Rendering Index (CRI) in Solar Street Lights
  • Main and secondary roads: ≥ 80.
  • Branch roads: ≥ 70.
  • Interchanges and tunnels: ≥ 85.
• Illuminance (lux)：What is Lux in Lighting? Solar Street Lighting Lux Level standard
  Main road: ≥30lux.
  Secondary road: ≥20lux.
  Branch: ≥15lux.
  Overpasses and toll plazas: ≥50lux.
  Tunnel: entrance section ≥100lux, exit section ≥80lux, middle section ≥50lux.

4. Installation Height and Spacing

• Installation Height
  • Main road: 10 meters.
  • Secondary road: 8 meters.
  • Branch road: 6 meters.
• Installation Spacing
  • Main road: 30 meters.
  • Secondary road: 40 meters.
  • Branch road: 50 meters.
• Solar Street Light Height and Distance Spacing Calculation

5. Pure Solar vs. Hybrid Solar and Grid Power

• Pure Solar System
  • Advantages: Completely relies on solar energy, zero electricity costs, environmentally friendly.
  • Disadvantages: May not ensure continuous lighting in prolonged rainy days or extreme weather conditions.
• Hybrid Solar and Grid System
  • Advantages: Automatically switches to grid power when solar energy is insufficient, ensuring continuity and reliability of the lighting system.
  • Disadvantages: Slightly higher initial investment; however, it is more economical in the long run.
• Recommended Solution: Considering the special needs and safety of highways, we recommend using a hybrid solar and grid power system. This ensures that lighting systems remain reliable and continuous during periods of insufficient solar energy.

6. Configuration Calculation Formulas

Solar Street Lights Design Guide: Key Calculations and Considerations

• Peak Sunlight Hour CalculationFormula: T = A / (3.6 × 365)Parameters:
  • A: Total radiation of the inclined surface over the last year (MJ/m²·a).
  • T: Peak sunlight hours (hours/day).
• Solar PV Component Capacity CalculationFormula: WP = PT1(17/12) / (T × 0.85 × 0.85)Parameters:
  • PT1: Daily power consumption of the load (Wh).
  • T: Peak sunlight hours (hours/day).
  • WP: Power of the solar PV component (W).
• Battery Capacity CalculationFormula: C = (D × F × Q × K_o × K_t) / (U × L × V)Parameters:
  • D: Maximum days without sunlight (days).
  • F: Correction factor for battery discharge efficiency (usually 1.05).
  • Q: Daily power consumption (Wh).
  • K_o and K_t: Line loss factors (usually 0.98).
  • U: Battery discharge depth (usually 0.6).
  • V: System operating voltage (V).
  • C: Battery capacity (Ah).
• Pole Spacing CalculationFormula: S = (L × H) / IParameters:
  • L: Light output of the fixture (lm).
  • H: Pole height (m).
  • I: Required illuminance (lux).
  • S: Pole spacing (m).
• Uniformity CalculationFormula: U = (Minimum Illuminance) / (Maximum Illuminance)Parameters:
  • U: Uniformity.
  • Minimum illuminance: Illuminance at the darkest point on the road (lux).
  • Maximum illuminance: Illuminance at the brightest point on the road (lux).

7. Case Studies

Los Angeles Highway Project

• Project Background: The Los Angeles Highway is located in California, USA, with an average annual solar radiation intensity of 1700 kWh/year and an average effective sunlight hour of 4.66 hours/day.
• Design Parameters:
  • Solar Panels: 150Wp monocrystalline solar panels, 24V output voltage, one per street light.
  • Batteries: 24V/100AH lithium-ion batteries to ensure normal operation during six consecutive days of rainy weather.
  • LED Lights: 100W LED lights, lumen output of 10,000lm, color temperature 5500K, CRI 85, uniformity 0.4.
  • Controller: 24V/30A intelligent controller with automatic switching and remote monitoring functions.
  • Installation Height: 10 meters.
  • Installation Spacing: 30 meters.
• Calculation Process:
  • Peak Sunlight Hour: T = (1700 × 3.6 × 1000) / (3.6 × 365) ≈ 4.66 hours/day
  • PV Component Capacity: WP = (1000 × 3 × 1.05 × 0.98) / (4.66 × 0.85 × 0.85) ≈ 300 W
  • Battery Capacity: C = (3 × 1.05 × 1000 × 0.98) / (0.6 × 24) ≈ 200 Ah

Sydney Highway Project

• Project Background: The Sydney Highway is located in New South Wales, Australia, with an average annual solar radiation intensity of 1900 kWh/year and an average effective sunlight hour of 5.2 hours/day.
• Design Parameters:
  • Solar Panels: 150Wp monocrystalline solar panels, 24V output voltage, one per street light.
  • Batteries: 24V/100AH lithium-ion batteries to ensure normal operation during six consecutive days of rainy weather.
  • LED Lights: 70W LED lights, lumen output of 7,000lm, color temperature 5000K, CRI 85, uniformity 0.4.
  • Controller: 24V/30A intelligent controller with automatic switching and remote monitoring functions.
  • Installation Height: 8 meters.
  • Installation Spacing: 40 meters.
• Calculation Process:
  • Peak Sunlight Hour: T = (1900 × 3.6 × 1000) / (3.6 × 365) ≈ 5.2 hours/day
  • PV Component Capacity: WP = (700 × 3 × 1.05 × 0.98) / (5.2 × 0.85 × 0.85) ≈ 240 W
  • Battery Capacity: C = (3 × 1.05 × 700 × 0.98) / (0.6 × 24) ≈ 150 Ah

Berlin Highway Project

• Project Background: The Berlin Highway is located in Germany’s capital, with an average annual solar radiation intensity of 1200 kWh/year and an average effective sunlight hour of 3.3 hours/day.
• Design Parameters:
  • Solar Panels: 150Wp monocrystalline solar panels, 24V output voltage, one per street light.
  • Batteries: 24V/100AH lithium-ion batteries to ensure normal operation during six consecutive days of rainy weather.
  • LED Lights: 100W LED lights, lumen output of 10,000lm, color temperature 5500K, CRI 85, uniformity 0.4.
  • Controller: 24V/30A intelligent controller with automatic switching and remote monitoring functions.
  • Installation Height: 10 meters.
  • Installation Spacing: 40 meters.
• Calculation Process:
  • Peak Sunlight Hour: T = (1200 × 3.6 × 1000) / (3.6 × 365) ≈ 3.3 hours/day
  • PV Component Capacity: WP = (1200 × 3 × 1.05 × 0.98) / (3.3 × 0.85 × 0.85) ≈ 300 W
  • Battery Capacity: C = (3 × 1.05 × 1200 × 0.98) / (0.6 × 24) ≈ 200 Ah

8. International Lighting Standards

• CIE (International Commission on Illumination) Standards
  • CIE 115: Road lighting standard specifying brightness, illuminance, uniformity, glare limits, and other technical indicators.
  • CIE Pub No. 12-2 (TC 4-6): Provides detailed guidance for road lighting design, including fixture arrangement, installation height, and lamp spacing.
• U.S. Standards
  • IESNA (Illuminating Engineering Society of North America) Standards: Provides detailed lighting design guidelines, including illuminance, uniformity, glare limits, etc.
  • ANSI C136.10: Specifies performance and testing standards for road lighting equipment.
• European Standards
  • EN 13201: Road lighting design standard specifying illuminance, uniformity, glare limits, and other technical requirements.
  • EN 50176: Specifies performance and testing standards for road lighting equipment.

9. Economic and Environmental Benefits

• Electricity Consumption: The photovoltaic solar street light system at the Los Angeles Highway project can save 6000 kWh of grid electricity per day, equating to 2,190,000 kWh of savings annually.
• Converted to Standard Coal: Equivalent to 788,400 kg.
• Converted to Diesel: Equivalent to 495,000 kg.
• Pollutant Emission Reduction: One year of usage could reduce SO₂ by 15,768 kg, CO₂ by 354,720 kg, soot by 11,826 kg, and ash by 199,200 kg.
• Cost Analysis:
  • Initial Investment: Although the initial investment is high, costs can be reduced through optimized design.
  • Long-Term Returns: Zero electricity costs, no safety hazards, zero emissions, and easy installation significantly enhance economic benefits in the long run.

10. Installation and Maintenance

Installation Steps:

1. Foundation Construction: Ensure the pole foundation is solid and meets wind-resistance and lightning protection requirements.
2. Pole Installation: Use specialized tools to secure the poles on the foundations, ensuring verticality.
3. Solar Panel Installation: Secure the panels on the top of the poles at the optimal angle.
4. Fixture Installation: Mount the LED fixtures securely to the poles, ensuring proper lighting direction.
5. Wiring Connections: Connect solar panels, batteries, controllers, and fixtures, ensuring reliable wiring connections.

Maintenance Recommendations:

• Regular Inspections: Check the status of solar panels and fixtures once a month, cleaning dust and dirt.
• Battery Maintenance: Inspect battery voltage and capacity annually, replacing if necessary.
• Controller Maintenance: Test controller functions annually to ensure they work correctly.
• Lightning Protection System Check: Verify the effectiveness of the lightning protection system annually to ensure reliability.

Comprehensive Guide to Installing Solar Street Lights

12. Conclusion

By following this design guide, engineers and designers can create efficient, reliable, and sustainable solar highway lighting systems. The best configurations not only ensure normal operation of systems but also deliver significant economic and environmental benefits.
We hope this guide provides valuable references for your projects. If you have any questions or require further technical support, please feel free to contact our technical support team.

Related must-read articles

Solar Street Lights Battery Comprehensive guide