THE AGL ENGINEERING CENTRE by Precision AGL Academy · Solar Airfield Ground Lighting

Solar Airfield Ground Lighting (SAGL)

A practical engineering guide to solar-powered runway, taxiway and airport visual lighting systems. SAGL is an airfield visual-lighting arrangement in which photovoltaic energy is converted into electrical energy, stored in batteries where required, and used to operate aviation lighting equipment. Unlike conventional centralized AGL — which commonly depends on an electrical distribution network, CCRs, series circuits and isolation transformers — solar AGL can distribute the energy source directly at or close to individual lighting units, making it especially useful for remote, small, off-grid, temporary or infrastructure-constrained applications.

Overview

What Is Solar Airfield Ground Lighting?

A solar light is an integrated chain, not just a lamp: panel, controller, battery, driver, light and optics.

MORE THAN A SOLAR LAMP · ONE INTEGRATED VISUAL-AID SYSTEM SOLAR PANELphotovoltaic energy CONTROLLERregulates the charge BATTERYstores energy LED DRIVERsets current and dimming LIGHT + OPTICSsource and optical system ALSO IN THE SYSTEMradio receiver · remote controller · control and monitoring electronics · GPS or timing · antenna · mounting structure · anchorage THE QUESTION: CAN THE COMPLETE SYSTEM PROVIDE THE REQUIRED GUIDANCE? SCHEMATIC · COMPONENT SET VARIES BY DESIGN
Figure 1. Solar AGL as an integrated system: the main chain, the supporting components and the engineering question.
AGL Visual Encyclopedia: Renewable energy integration Energy-efficient AGL Portable PAPI

Solar AGL is an airfield-lighting system powered partly or entirely by photovoltaic energy. A typical unit integrates a solar panel, charge controller, rechargeable battery, LED driver, aviation light source and optical system — with additional components such as a radio receiver, remote controller, control/monitoring electronics, GPS or timing system, communication antenna, mounting structure and mechanical anchoring system.

The FAA is currently evaluating decentralized solar lighting at General Aviation airports, including runway and taxiway edge lights, obstruction lights, runway guard lights, windsocks and guidance signs — its research specifically evaluates reliability, safety, photometric and design compliance, and siting requirements.

A solar runway light is an equipment item. A solar AGL system is an integrated aviation visual-aid system. The engineering question is therefore not only "Does the solar lamp work?" — it is "Can the complete system reliably provide the required visual guidance for the intended operation?"

More Than a Solar Lamp

A solar AGL system is an integrated aviation visual-aid system — energy, storage, electronics, optics, geometry, control and environment must all work together.

Decentralized, Not Uncontrolled

Solar AGL can remove much of the conventional centralized distribution architecture — but "decentralized" does not mean the system can go unmonitored or unverified.

FAA Solar Research

The FAA's decentralized solar-lighting research evaluates reliability, safety, photometric compliance, design compliance, solar suitability and siting requirements across multiple visual-aid types.

Comparison

Conventional AGL vs Solar AGL

ParameterConventional AGLSolar AGL
Energy sourceUtility / generatorSolar energy
StorageUsually centralized backupLocal battery
DistributionSeries circuit / common infrastructureDecentralized
CCRCommonly usedUsually not required for standalone units
Isolation transformerCommon in series circuitsNormally not part of standalone architecture
CablingExtensive underground networkMinimal or local wiring
ControlCentralizedLocal, wireless or hybrid
InstallationFixed infrastructureDecentralized units
Grid dependenceHighLow or none
Site dependencyElectrical infrastructureSolar resource and environmental conditions
Why It Matters

Why Solar AGL Is Important

Solar technology can reduce the need for extensive electrical infrastructure at locations where grid-connected AGL would be difficult or expensive. FAA airport technology research specifically identifies solar as an alternative for small, remote and off-grid airports.

Reduced cable infrastructure Reduced trenching Reduced dependence on centralized power Easier deployment in remote locations Independent operation of individual units Local energy storage Potentially lower infrastructure complexity
These advantages do not eliminate the need for aviation-grade design and verification.
Applications

Where Solar AGL Can Be Used

Runway Edge Lighting

Can potentially eliminate the need for a conventional underground cable network.

Taxiway Edge Lighting

Independent lighting where underground cable infrastructure is impractical.

Threshold & Runway End Lighting

Correct colour, quantity, spacing and orientation relative to edge lighting.

REIL Systems

Additional flashing, intensity, synchronisation and control considerations apply.

Obstruction Lighting

Particularly useful for isolated obstructions where grid connection is difficult.

Runway Guard Lighting

Part of the runway-incursion prevention arrangement — control and fail-safe behaviour matter.

Airfield Guidance Signs

Internally illuminated signs with day/night control and battery-backed operation.

Windsock Lighting

Illumination for visual wind indicators with defined operating periods.

Temporary & Remote Lighting

Construction, emergency, remote airfields and temporary runway configurations.

The suitability of solar equipment depends on the exact operational requirement and applicable standards.
Where It Fits Best

Remote Airfields & Small General Aviation Airports

Remote Airfields

Solar AGL is especially relevant where grid power is unavailable, cable installation is difficult, the runway is far from the electrical substation, terrain is difficult, infrastructure development is expensive, airport operations are intermittent, or independent lighting units are desirable. The site should nevertheless undergo proper engineering evaluation before deployment.

Small General Aviation Airports

The FAA is evaluating solar-powered lighting at General Aviation airports as part of its ongoing airport technology research. Its test arrays include several types of airfield visual aids — solar AGL should be viewed as a potential system architecture, not simply an alternative lamp technology.

Deployment Duration

Temporary vs Permanent Decentralized SAGL

Temporary Solar AGL

Used for construction, emergency restoration, temporary runway configuration, remote works, temporary taxi routes and short-duration operations. The designer should consider both the solar energy system and the approved temporary airfield layout.

Permanent Decentralized Solar AGL

A typical concept: individual light + integrated PV + battery + local control + wireless communication — removing much of the conventional centralized distribution architecture. However, "decentralized" does not mean "uncontrolled."

Architecture

Basic Solar AGL Architecture

Sunlight
PV Module
Charge Controller
Battery
LED Driver
LED Optical Assembly
Airfield Visual Guidance
Control Path (Operates in Parallel)
Radio Command
Controller
Lighting Unit
Diagram

Solar AGL Reliability Chain

System reliability cannot be described using LED lifetime alone — every stage in the chain has its own failure possibility, and a fault anywhere breaks the visual guidance function.

Sun available → PV healthy → controller healthy → battery healthy → driver healthy → LED healthy → optics correct

SUN Irradiance available PV Panel healthy CHARGE CTRL Controller healthy BATT Battery healthy DRVR Driver healthy LED LED healthy OPTIC CORRECT Final visual output
LED lifetime is not equivalent to system lifetime — the complete solar light still contains a battery, electronics, seals, connectors, PV components and optical components, each with its own failure mode.
Energy Fundamentals

Photovoltaic Energy Conversion & Solar Radiation

Solar panels convert incident solar radiation into electrical energy. The actual energy available varies — therefore rated panel wattage alone is not sufficient for system sizing.

Solar irradiance Panel orientation Panel area Temperature Shading Dust Cloud cover Atmospheric conditions Seasonal variation Latitude Time of day Horizon obstruction Panel inclination
A site with strong annual sunlight may still have difficult periods during monsoon, winter, prolonged cloud cover or dust events — design around the worst-case period, not the annual average.
Energy Chain

Solar AGL Energy Chain & Panel Sizing

Solar Irradiance
PV Conversion
Charge Controller
Battery Storage
Electronic Conversion
LED
Optical Output

Every stage introduces losses, so PV capacity must be sized against the entire system energy requirement, not only the LED rating.

Daily PV Energy ≈ PV Capacity × Effective Solar Hours × System Efficiency

System efficiency accounts for losses in PV conversion, charge controller, battery charging, battery discharge, wiring and driver electronics. The actual design should use site-specific solar data.

LED Load — A Reminder

LED technology is highly useful for solar AGL because LEDs generally provide high luminous efficiency compared with older light-source technologies. However: low electrical power ≠ low engineering requirement. The LED still needs to produce the required intensity, colour, beam distribution, angular coverage and reliability.

Storage

Battery Storage & Autonomy

The battery provides energy when solar generation is unavailable, making it one of the most critical components in a solar AGL system.

CapacityVoltageChemistryCycle life TemperatureDepth of dischargeCharging characteristics Self-dischargeAgeMaintenanceReplacement interval

Battery Autonomy is the period for which the system can operate without meaningful solar charging.

Required autonomy = expected no-sun operating period + design reserve

The required value should be determined from the operational requirement, site climate, lighting duty cycle and applicable design criteria. Do not use a generic autonomy figure for every airport.

Worked Example

Energy Budget & Example Calculation

Daily energy consumption = lighting load + control load + communication load + monitoring load, then add allowances for charge losses, battery losses, temperature effects, aging, reserve capacity and seasonal solar availability.

Example: a unit uses a 10 W LED system for 10 hours/night → Lighting energy = 10 W × 10 h = 100 Wh/night. Once controller and battery losses are included, the required stored energy will be greater than 100 Wh. A simple "10 W × 10 hours" calculation is not enough for final system sizing.

Interactive

Solar AGL Sizing Estimator

Adjust the sliders for a single lighting unit to see a simplified planning estimate for daily energy, required battery capacity, and required PV capacity. This is a conceptual sizing tool only.

8 W
11 hrs
3 days
5 hrs
Daily Lighting Energy
0 Wh
Required Battery Capacity (12V)
0 Ah
Required PV Capacity
0 Wp
Assumes a 70% overall system efficiency and an 80% usable battery fraction. Final sizing requires site-specific solar resource data, battery chemistry limits, temperature effects, aging allowance and the manufacturer's system methodology.
Duty Cycle & Control

Duty Cycle, Pilot Control & Wireless Networking

Duty Cycle

Not every visual aid operates continuously — continuous operation, reduced intensity, standby mode, pilot activation, scheduled, flashing or event-driven operation each strongly affect energy consumption.

Pilot-Controlled SAGL

Pilot command → radio receiver → local controller → lighting units. The exact control arrangement must be designed and tested for the equipment and operational environment.

Wireless Networking

Used for ON/OFF commands, intensity control, status feedback, fault reporting, battery information, configuration and remote diagnostics via radio, proprietary RF, mesh, cellular or other site-specific technology.

Wireless Failure

Communication loss, interference, receiver failure, antenna damage, software fault, power loss or configuration error — the design should define what happens when communication is unavailable.

Local Autonomy

An individual light can potentially keep operating even if the central network or adjacent lights fail — but this behaviour is equipment-specific and must not be assumed without documentation.

Centralized vs Decentralized

Centralized: control centre → network → field equipment. Decentralized: local controller → individual unit. Hybrid: central control → wireless network → local autonomous control.

Control Architecture

Centralized, Decentralized & Hybrid Control

Centralized
Control Centre → Network → Field Equipment
Decentralized
Local Controller → Individual Unit
Hybrid
Central Control → Wireless Network → Local Autonomous Control

Each architecture has different failure modes. A distributed system can make single-unit failures easier to isolate, but whether a single failure is operationally acceptable depends on light function, location, pattern, required serviceability and applicable operating rules. Do not treat decentralization as automatic redundancy.

Failure Analysis

Single, Multiple & Common-Cause Failure

Single Light Failure

Depends on light function, location, pattern, required serviceability, applicable operating rules and failure distribution — not automatically acceptable just because it's an isolated unit.

Multiple-Light Failure

The more important question is often "what happens when several adjacent lights fail?" — possible causes include severe weather, battery depletion, communication failure, charging failure or control malfunction.

Common-Cause Failure

Poor solar siting, extended cloud cover, incorrect configuration, firmware problems, radio interference, excessive dust or a battery design problem can affect many individual units simultaneously.

Redundancy Strategy

Conventional AGL uses multiple feeders, separate transformers, backup power and central monitoring. Solar AGL instead uses distributed units, individual storage, multiple independent power sources, wireless redundancy and local autonomous operation.

Siting

Panel Orientation, Integrated Geometry & Shading

Solar Panel Orientation

Geographic location, solar path, panel angle, seasonal performance, horizon obstruction and airfield geometry all affect energy production. The best solar orientation and the best aviation-light orientation are not necessarily the same.

Integrated Solar-Light Geometry

Panels may be mounted directly on the light housing, or use separate panels, adjustable brackets, multiple panels, vertical PV surfaces or remote PV modules. The mechanical arrangement should maintain required aviation visibility while maximizing energy collection.

Shading

Buildings, trees, vehicles, aircraft, fences, signs, structures, terrain and even other solar units can shade a panel — a panel partially shaded for part of the day may significantly reduce energy production.

Airfield Shading Study — Check Throughout the Day

A site that appears unobstructed at noon may have significant morning or evening shading — inspect across the full expected solar path and seasonal changes

Obstruction SOLAR PANEL Morning Long shadow — panel likely shaded Midday Minimal shadow Evening Long shadow — check evening exposure
Environmental Factors

Soiling, Temperature & Battery Chemistry

Five factors that decide how a solar light performs: soiling, temperature, chemistry, battery management and the controller.

SOILING, TEMPERATURE AND BATTERY CHEMISTRY SOILING Dust from aircraft movement, construction, unpaved shoulders, wind and vehicles. The plan sets inspection frequency, cleaning method, water, safety and damage checks. TEMPERATURE PV and battery performance both depend on it: daytime highs, night lows, seasons and enclosure temperature. Thermal design matters in hot climates. BATTERY CHEMISTRY Lead-acid, AGM, gel and lithium differ in temperature tolerance, cycle life, weight, maintenance, safety, cost and charging strategy. BATTERY MANAGEMENT (LITHIUM) Cell monitoring, overcharge, over-discharge, over-temperature and current protection, and balancing. The design depends on the chemistry. CHARGE CONTROLLER Charge regulation, overcharge protection, load management, low- voltage disconnect and battery monitoring, using MPPT or PWM. AVOID AGGRESSIVE CLEANING THAT CAN DAMAGE THE PV SURFACE SCHEMATIC · SUMMARY OF THE FACTORS · NOT A SIZING TOOL
Figure 2. Soiling, temperature, battery chemistry, battery management and charge controller functions, summarised from the section text.
AGL Visual Encyclopedia: Renewable energy integration Asset health monitoring

Solar Panel Soiling & Cleaning

Dust accumulates from aircraft movement, construction, unpaved shoulders, wind and vehicle traffic. A maintenance plan should specify inspection frequency, cleaning method, water requirements, cleaning safety and damage inspection — never use aggressive cleaning methods that can damage PV surfaces.

Temperature Effects

PV and battery performance both depend on temperature — high daytime temperature, low nighttime temperature, seasonal changes and enclosure temperature all matter. Thermal design is therefore important in hot climates.

Battery Chemistry

Lead-acid, AGM, gel, lithium-based and other rechargeable chemistries each differ in temperature tolerance, cycle life, weight, maintenance, safety, cost, replacement availability and charging strategy.

Battery Management System

Lithium-based systems commonly require cell monitoring, overcharge protection, over-discharge protection, over-temperature protection, current protection and balancing — the exact architecture depends on battery chemistry.

Charge Controller & MPPT

The controller manages charge regulation, overcharge protection, load management, low-voltage disconnect and battery monitoring, using MPPT or PWM. MPPT can extract more usable energy under changing solar conditions where panel and battery voltages differ significantly.

LED Driver & Intensity Control

The driver must maintain appropriate current, voltage, regulation, protection and dimming behaviour — a poor driver can reduce optical stability even when battery and PV are healthy. Higher intensity means higher energy demand, so intensity, battery capacity and PV capacity should be designed together.

Photometry

Photometry Remains Essential

A solar light is still an aviation light. Solar technology changes the energy source, not the fundamental visual-aid requirement.

Do not determine compliance only by asking "Can I see the light?" — a light can be visibly bright and still have an incorrect photometric distribution.
Colour
Candela
Coverage
Configuration

A perfectly charged battery cannot correct an incorrectly aimed light. Check runway axis, taxiway axis, threshold orientation, runway end orientation, light azimuth, light elevation and spacing. Photometry + geometry = useful engineering verification.

Application-Specific Engineering

Solar Light Types & Their Particular Considerations

Seven solar light types and the main checks each one still needs.

SOLAR LIGHT TYPES · WHAT EACH ONE MUST STILL GET RIGHT EDGE Geometry, spacing, colour, orientation, stability and power endurance. THRESHOLD Correct colour, quantity, spacing and orientation. REIL Flash pattern, synchronisation, beam direction and control. APPROACH Geometry, positioning, pattern, stable power and approval. PAPI Geometry, elevation, aiming, surveying and photometrics. OBSTRUCTION Battery autonomy matters most where access is limited. SIGNS Sign brightness, day and night. A GENERIC SOLAR BEACON CANNOT BE ASSUMED TO PERFORM AS A REIL SCHEMATIC · MAIN CHECKS ONLY · SEE THE SECTION TEXT FOR THE FULL LIST
Figure 3. Solar light types: edge, threshold, REIL, approach, PAPI, obstruction and sign lights, with the main checks for each.
AGL Visual Encyclopedia: Portable PAPI PAPI system overview Low-intensity obstruction lights
EDGE

Runway & Taxiway Edge

Verify runway/taxiway geometry, light spacing, colour, intensity, orientation, mechanical stability and power endurance — particular attention at intersections, holding positions, curves, aprons and construction zones.

THRESHOLD

Threshold & Runway End

Correct colour, quantity, spacing and orientation, and a clear relationship with runway edge lights, are essential for correct runway-end communication to approaching/departing aircraft.

REIL

Runway End Identifier

Evaluate flashing pattern, intensity, beam direction, synchronisation, control and visibility. Do not assume a generic solar beacon can perform the function of an aviation REIL.

APPROACH

Approach Lighting

Considerably more complex than edge lighting — needs defined geometry, accurate positioning, correct visual pattern, stable power, appropriate optical output, suitable mechanical supports and operational approval.

PAPI

Solar PAPI

PAPI is not merely a lamp — precise geometry, elevation, aiming angles, unit relationship, surveying, photometric characteristics and approach-path considerations all apply. A solar power supply does not simplify these requirements.

OBSTRUCTION

Obstruction Lighting

Particularly useful for isolated obstructions where grid connection is difficult — solar sizing and battery autonomy are especially important because maintenance access may be limited.

SIGNS

Airfield Guidance Signs

Consider sign brightness, day/night control, LED load, battery capacity, solar panel sizing, communication and inspection access.

WINDSOCK

Windsock Lighting

Consider required operating period, windcone location, battery autonomy, environmental exposure, visibility and maintenance access.

GUARD

Runway Guard Lighting

Part of the runway-incursion prevention arrangement — evaluate location, control, fail-safe response and monitoring, not as a simple replacement lamp.

Critical Rule

Solar AGL, CCRs & Isolation Transformers

A standalone solar lighting unit usually does not use the conventional CCR → 6.6 A series circuit architecture — instead it commonly uses PV → battery → LED driver. This is one of the biggest conceptual differences between conventional and decentralized solar AGL. Standalone solar units generally do not require the isolation-transformer architecture used in a conventional constant-current series circuit.

Never connect a solar unit to a conventional 6.6 A series circuit without equipment-specific technical justification. Any hybrid system connected to conventional AGL infrastructure must be specifically engineered.
Hybrid Systems

Hybrid Solar AGL

Sources, conversion and control, then airfield power: where solar sits in a wider supply.

RENEWABLE-ENERGY INTEGRATION · CLEANER SUPPLY, SAME CERTIFIED AGL ADD RENEWABLE SUPPLY · KEEP BACKUP POWER · NEVER RISK THE LIGHTS 1 SOURCES Solar PV array Wind, where permitted Battery storage STAGE: generation 2 CONVERT Inverters Energy management Storage smooths supply STAGE: control 3 SUPPLY Substation, distribution Grid connection Secondary supply kept STAGE: supply 4 AGL LOAD CCRs Series circuits Lights unchanged STAGE: load GRID + STANDBY SUPPLY BACK UP THE RENEWABLES · CHANGEOVER STAYS WITHIN REQUIRED TIMES WELL SUITED TO CLEANER · LOWER-COST ENERGY Less grid demand, more resilience with storage LIMITS SITING · CONTINUITY · APPROVAL Glare, height, interference checked; backup kept DONE WITHIN THE APPROVED DESIGN, SAFETY ASSESSMENT AND REGULATOR REQUIREMENTS SCHEMATIC · SIMPLIFIED · NOT TO SCALE · ARRANGEMENT VARIES BY SITE AND UTILITY
Figure 4. Renewable-energy integration in AGL: sources, conversion and control, and airfield power.
AGL Visual Encyclopedia: Renewable energy integration Standby power and UPS

A hybrid system can combine solar, battery, grid and generator sources to improve operational flexibility.

Solar

Primary energy

Battery

Energy storage

Grid

Auxiliary charging

Generator

Emergency backup

Solar + Grid Charging

A hybrid controller can allow batteries to be charged from solar PV, a grid AC/DC system, or a generator — such systems require suitable power-management logic and protection.

Solar + Generator

A generator can serve as backup when solar generation is insufficient, battery state of charge is low, prolonged bad weather occurs, or emergency operations extend beyond normal design assumptions. Automatic generator integration requires additional control engineering.

"Solar powered" does not necessarily mean 100% energy independent under all conditions — the system remains dependent on solar availability, battery health, electronics, panel condition and environmental conditions.
Design Margin

Worst-Case Conditions, Reserve Margin & Sizing Sequence

System design should consider the period when energy demand is high and solar energy availability is low — this is typically more important than designing around average annual sunlight. Before designing, obtain site-specific data for global irradiation, seasonal variation, effective peak sun hours, cloud conditions, temperature and historical weather. A site-specific energy model is preferable to generic internet-based assumptions.

A solar AGL system should not normally be designed so that daily solar generation ≈ daily load with no reserve — weather varies, panels soil, batteries age, temperatures change and system losses vary.

System Sizing Sequence
1

Determine operational duty

2

Calculate electrical load

3

Determine required autonomy

4

Determine battery energy

Required battery energy ≈ Daily load × Required autonomy ÷ usable battery fraction, with allowances for temperature, aging, conversion and wiring losses.

5

Determine PV energy requirement

PV capacity ≈ Required daily energy ÷ (Effective solar energy × system efficiency).

6

Select PV module, controller & LED system

7

Validate against worst-case conditions

Mechanical & Safety

Environmental Protection, Anchorage & Aircraft Clearance

Exposure, water ingress, anchorage, aircraft clearance and frangibility checked as one assembly.

ENVIRONMENT, ANCHORAGE AND AIRCRAFT CLEARANCE EXPOSURE Rain, dust, UV, heat, humidity, salt, wind, jet blast, wildlife and insects. WATER INGRESS POINTS Compartments, cable glands, connectors, housing joints, switches, antennas and PV connections. Failures are often intermittent or delayed. ANCHORAGE Impact, wind, jet blast, ground movement, vibration and vehicles. After strong wind or blast, check movement, tilt, foundation, brackets and cables. AIRCRAFT CLEARANCE Panels can be larger than conventional fixtures: check the strip, obstacle-free areas, clearance surfaces, wingtip, propeller and jet blast exposure. FRANGIBILITY Where required, evaluate the complete assembly: light, panel, support and foundation. A COMPLIANT LAMP ON AN UNSUITABLE SUPPORT DOES NOT MAKE A COMPLIANT ASSEMBLY SCHEMATIC · SUMMARY OF THE CHECKS · FOLLOW THE APPLICABLE STANDARD
Figure 5. Environmental protection, anchorage, aircraft clearance and frangibility checks for a solar airfield light.
AGL Visual Encyclopedia: Moisture ingress Sealing system Water ingress prevention

Environmental Exposure

Rain, dust, UV, heat, humidity, salt, wind, jet blast, wildlife and insects — selected equipment should be suitable for the environmental conditions of the installation.

Corrosion & Water Ingress

Corrosion can affect mounting hardware, battery terminals, connectors, PV structures, housing and fasteners. Water ingress points include compartments, cable glands, connectors, housing joints, switches, antennas and PV connections — often causing intermittent or delayed failure.

Mechanical Protection & Anchorage

Consider impact, wind, jet blast, ground movement, vibration, maintenance activity and vehicle exposure. After strong wind or jet-blast exposure, inspect for movement, tilt, foundation movement, bracket damage and cable displacement.

Safety

Electrical protection, battery protection, mechanical stability, aircraft clearance, personnel safety, fire considerations, cable safety and maintenance access — battery technologies with specific thermal or chemical hazards need additional protection.

Aircraft Clearance

Solar panels can be physically larger than conventional fixtures — check against runway/taxiway strip, obstacle-free areas, clearance surfaces, wingtip clearance, propeller clearance and jet blast exposure.

Frangibility

Where frangibility is required, the complete assembly — light, solar panel, support and foundation — must be evaluated. A compliant lamp attached to an unsuitable support does not automatically make the complete installation compliant.

Deployment Type

Portable vs Fixed Solar AGL

Portable PAPI units on temporary legs, fed by a battery or solar power box.

PORTABLE PAPI A PORTABLE SET, SEEN FROM ABOVE ONE UNIT, SEEN FROM THE SIDE RUNWAY THRESHOLD POWER BOX battery · solar · AC BEAMS FACE THE APPROACH FOUR UNITS · EQUAL SPACING · SAME ANGLE WHITE · ABOVE RED · BELOW LEGS ADJUST ANGLE AND LEVEL SOLAR KIT BATTERY or generator · AC PORTABLE PAPI AT A GLANCE Unitsfour (PAPI) · two (APAPI) Mountingtemporary legs Powerbattery, solar, generator or AC SCHEMATIC · SPACING, ANGLES AND DISTANCES COME FROM THE STANDARD AND THE MANUFACTURER · NOT TO SCALE
Figure 6. Portable PAPI: four units beside a runway on temporary legs, powered by a battery or solar power box.
AGL Visual Encyclopedia: Portable PAPI Temporary runway lighting for works

Portable Solar AGL

Designed primarily for rapid deployment, temporary use, emergency response and construction. See our Portable Airfield Ground Lighting (PAGL) guide for the complete portable-lighting engineering picture.

Fixed Solar AGL

Designed for longer-term deployment, remote infrastructure, dedicated airfield applications and permanent or semi-permanent installations. Applicable design and certification requirements can differ between portable and fixed solar equipment.

Testing

Solar AGL Testing

Electrical

Battery, charging, current, voltage.

Optical

Intensity, colour, beam distribution.

Solar

Charging performance and energy production.

Mechanical

Stability and anchoring.

Control & Communication

Local and remote commands; range and reliability where applicable.

Operational

Correct visual pattern and configuration.

Solar Charging Test
Starting Battery State
Solar Input
Charging Current
Battery Voltage
Charge Duration
Final State

Night-Endurance Test

Assesses initial battery state, lighting intensity, operating duration, battery voltage, low-voltage protection, automatic dimming and shutdown behaviour — performed under controlled conditions and interpreted against the design requirement.

Photometric Test During Battery Discharge

Particularly valuable — a solar light may start the night with adequate intensity but perform differently after extended discharge. Evaluate both the beginning and end of the required operating period; performance must be maintained throughout.

Maintenance

Solar AGL Maintenance Checklist

Click any item to mark it complete.

PV & Panel

PV panel inspected
Panel cleanliness checked
Panel damage checked
Alignment verified
0 / 4 complete

Battery & Electrical

Battery checked
Battery terminals checked
Charge controller checked
Connector inspected
0 / 4 complete

Optical & Housing

LED operation checked
Lens checked
Housing checked
Photometric condition checked
0 / 4 complete

Control & Structural

Anchoring checked
Radio / control checked
Structural condition checked
0 / 3 complete
Troubleshooting

Troubleshooting Solar AGL

Light OFF
Check Battery
Check Controller
Check LED Driver
Check LED
Check Command
Check Communication
Check Wiring / Connectors

Then ask: why did the battery become discharged? This second question is essential.

Suppose the light is OFF and battery voltage is low. Replacing the battery may restore the light — but the real cause could be a damaged PV panel, a failed charge controller, a heavily soiled panel, or incorrect charging configuration. A replacement without root-cause analysis only resets the failure.
Fault Classification
Energy — PV / battery / charging Electrical — driver / wiring / protection Optical — intensity / colour / beam Mechanical — housing / support / anchoring Geometric — position / azimuth / elevation Communication — radio / receiver / network Environmental — dust / water / temperature / wind Operational — incorrect configuration / procedure
Diagnostics

Common Solar AGL Failures

Tap a symptom to see possible causes.

Battery does not charge

Possible Cause

  • PV panel damaged or disconnected
  • Charge controller failure
  • Heavily soiled panel
  • Incorrect charging configuration

Battery charges but light output is low

Possible Cause

  • LED driver fault
  • Battery degradation
  • Optical contamination
  • Wrong operating mode

Light works only for a few hours

Possible Cause

  • Battery aged / reduced capacity
  • Undersized PV for the load
  • Excessive duty cycle
  • Poor charging during the day

Solar panel is shaded

Possible Cause

  • New obstruction (building, vegetation, vehicle)
  • Seasonal sun-angle change
  • Adjacent structure or aircraft

Light has moved from surveyed position

Possible Cause

  • Wind or jet-blast displacement
  • Loose anchoring
  • Ground movement
  • Vehicle/maintenance contact

Wireless control does not work

Possible Cause

  • Communication loss / interference
  • Receiver or antenna failure
  • Software fault
  • Network configuration error

LED healthy but beam misaligned

Possible Cause

  • Housing rotated or tilted
  • Incorrect mounting angle
  • Bracket movement

Connector moisture ingress

Possible Cause

  • Damaged seal
  • Loose connector
  • Cable gland failure
  • Housing joint failure
Common Mistakes

Solar AGL Common Mistakes

Sizing the panel from LED wattage alone Using average annual sunlight without checking critical periods Ignoring battery aging Ignoring temperature Treating a visible light as a photometrically compliant light Ignoring panel shading Ignoring dust Ignoring physical movement Assuming wireless control is always reliable Calling a solar product "ICAO/FAA compliant" without checking the exact applicable requirement
Standards

Standards & Regulatory References

FAA

AC 150/5345-50B (portable runway/taxiway lights and REIL for temporary use) and AC 150/5345-46F (Specification for Runway, Taxiway, Heliport, and Vertiport Light Fixtures) are both currently listed as active. The FAA has also published research material on solar-powered lighting and airport solar technology, with its current airport-technology program evaluating decentralized solar lighting to inform future guidance.

FAA Solar Research

Current research evaluates reliability, safety, photometric compliance, design compliance, solar suitability and siting requirements — across multiple visual-aid types, showing solar AGL is being assessed as an integrated airport infrastructure concept, not only a runway-edge product.

ICAO

Solar technology does not replace the applicable aerodrome visual-aid requirements. The actual applicable ICAO, national and airport-specific requirements must be established for the particular project.

National

DGCA / State aviation authority requirements, approved airport drawings and specifications, and airport operational procedures and approvals as applicable.

There is an important distinction between solar technology requirements and aviation visual-aid requirements. The solar system provides the energy; the airfield visual-aid requirements determine what the resulting aviation lighting system must achieve. The designer should identify the applicable visual-aid specification, photometric requirement, equipment specification, aerodrome design requirements, national aviation authority requirements and airport-specific requirements.

Design Workflow

Solar AGL Design Workflow

Site

Assess solar resource

Operation

Define hours & modes

Load

Calculate demand

Storage

Size battery & autonomy

Generation

Size PV for worst case

Electronics

Select controller & driver

Optics

Verify photometry

Geometry

Verify location & alignment

Mechanical

Anchoring & resistance

Control

Local/remote operation

Monitoring

Fault & status

Testing

Electrical/solar/optical/mechanical

Documentation

Record installation

Quick Reference

Solar AGL Quick Reference & Four Key Questions

PV Generation Battery Storage LED Aviation Lighting Control Communication Correct Geometry Photometric Performance Environmental Protection Operational Verification

Four questions every Solar AGL engineer should ask:

  1. Is there enough solar energy?
  2. Is there enough stored energy?
  3. Is the light producing the required optical performance?
  4. Is the complete installation correctly positioned and operationally suitable?
Engineering Model

The Final Solar AGL Engineering Principle

Solar AGL is not "AGL without cables." It is a different system architecture with a different set of engineering challenges. The engineer must simultaneously manage solar energy, battery storage, LED electronics, optics, geometry, control, communication, environmental conditions, mechanical stability and operational requirements.

The most important design question is not "How many watts is the solar panel?" It is: "Can this complete system reliably deliver the required aviation visual guidance throughout the intended operating conditions?"

Precision AGL Academy takeaway: the sun provides the energy, the battery provides continuity, the electronics control the light, and photometry proves what the pilot actually receives.

Test Yourself

Quick Knowledge Check

Q1. Why is rated PV panel wattage alone not sufficient for system sizing?

A. Because wattage ratings are always inaccurate
B. Because actual energy available varies with irradiance, orientation, temperature, shading, dust, cloud cover and season
C. Because panels never reach rated output
D. Because wattage only matters for battery sizing

Q2. A standalone solar lighting unit commonly uses which architecture, instead of a CCR / 6.6 A series circuit?

A. Isolation transformer → series circuit
B. Grid → CCR → LED
C. PV → battery → LED driver
D. Generator → transformer → LED

Q3. A light is OFF and the battery voltage is low. What should the engineer do first?

A. Investigate why the battery discharged before simply replacing it
B. Replace the battery immediately and close the ticket
C. Assume the LED has failed
D. Disconnect the unit permanently

Q4. Battery autonomy should be determined from:

A. A generic figure used for every airport
B. The LED manufacturer's default setting
C. Average annual sunlight only
D. The operational requirement, site climate, lighting duty cycle and applicable design criteria

Q5. Why can a solar light be electrically and optically healthy but still fail the photometric check?

A. Solar lights cannot fail photometric checks
B. Because it may be incorrectly aimed, positioned or configured — a perfectly charged battery cannot correct an incorrectly aimed light
C. Because photometric checks only apply to conventional AGL
D. Because LEDs are always photometrically compliant
Explore More

Explore More AGL Engineering

FOUNDATION

AGL Fundamentals

Build your understanding of the complete Airfield Ground Lighting system.

Open AGL Fundamentals →
ENGINEERING

AGL Design & Electrical Engineering

Layout, series circuits, CCR sizing, transformers, cable design and control.

Open AGL Design →
PERFORMANCE

AGL Photometry

Verify the optical performance of the installed system.

Open AGL Photometry →
TEMPORARY

Portable Airfield Ground Lighting

Temporary, emergency and rapid-deployment airfield lighting.

Open Portable AGL →
SYSTEMS

Runway Lighting Systems

Edge, threshold, end and centreline lighting in the permanent system.

Open Runway Lighting →
SYSTEMS

Taxiway Lighting Systems

Edge, centreline, lead-on/lead-off and stop-bar guidance.

Open Taxiway Lighting →
SOURCE

LED Airfield Ground Lighting

The LED engineering that pairs with PV-battery architecture in solar AGL.

Open LED AGL →
PROTECTION

Surge Protection & Lightning Mitigation

Protecting exposed PV-battery installations from transients.

Open Surge Protection →
VERIFICATION

AGL Testing & Inspection

Verifying off-grid systems before operational use.

Open Testing & Inspection →
SAFETY

Obstruction Lighting & Marking

A common application for standalone solar-powered lighting.

Open Obstruction Lighting →

Independent Power. Uncompromised Performance.

From PV sizing to battery autonomy, from anchoring to photometric verification — explore the complete AGL knowledge base for solar, portable and permanent lighting engineering.

AGL Engineering Hub

Explore the AGL Engineering Knowledge Hub

Fundamentals

Standards & Compliance

Runway, Taxiway & Approach Lighting

Surface Movement & Safety

PAPI

Electrical Engineering & Power

Photometry & Testing

Maintenance, Inspection & Safety

Resources, Documentation & Careers

FAQ

Frequently Asked Questions

Q1What is solar airfield ground lighting (SAGL)?

SAGL is an airfield-lighting system powered partly or entirely by photovoltaic energy, converted to electrical energy, stored in batteries where required and used to operate aviation lighting equipment. A typical unit integrates a solar panel, charge controller, rechargeable battery, LED driver, aviation light source and optical system.

Q2How does solar AGL differ from conventional AGL?

Conventional AGL uses utility or generator power, centralized backup, series-circuit distribution, CCRs, isolation transformers and extensive underground cabling with centralized control. Solar AGL uses solar energy with local batteries, decentralized units, minimal or local wiring and local, wireless or hybrid control. CCRs and isolation transformers are usually not required for standalone units.

Q3Is a solar runway light the same as a solar AGL system?

No. A solar light is an equipment item, while a solar AGL system is an integrated aviation visual-aid system. The engineering question is whether the complete system can reliably provide the required visual guidance for the intended operation.

Q4Why is solar AGL important?

It can reduce the need for extensive electrical infrastructure where grid-connected AGL would be difficult or expensive, and FAA airport technology research identifies solar as an alternative for small, remote and off-grid airports. Benefits include reduced cabling and trenching, easier deployment in remote locations, independent unit operation and local energy storage.

Q5Where can solar AGL be used?

Applications include runway and taxiway edge lighting, threshold and runway end lighting, REIL, obstruction lighting, runway guard lighting, airfield guidance signs, windsock lighting, and temporary and remote lighting. Suitability depends on the exact operational requirement and applicable standards.

Q6Where does solar AGL fit best?

Remote airfields where grid power is unavailable or cable installation is difficult, and small general aviation airports. The site should still undergo proper engineering evaluation before deployment.

Q7What is the FAA researching in solar airfield lighting?

The page says the FAA is evaluating decentralized solar lighting at General Aviation airports, including runway and taxiway edge lights, obstruction lights, runway guard lights, windsocks and guidance signs. The research evaluates reliability, safety, photometric and design compliance, solar suitability and siting requirements.

Q8Does decentralized solar AGL mean uncontrolled?

No. Solar AGL can remove much of the conventional centralized distribution architecture, but decentralized does not mean the system can go unmonitored or unverified.

Q9What is the difference between temporary and permanent solar AGL?

Temporary solar AGL is used for construction, emergency restoration, temporary runway configurations, remote works, temporary taxi routes and short-duration operations, and must consider both the solar energy system and the approved temporary layout. Permanent decentralized solar AGL typically combines an individual light with integrated PV, battery, local control and wireless communication.

Q10Do the advantages of solar remove the need for aviation-grade design?

No. These advantages do not eliminate the need for aviation-grade design and verification. Energy, storage, electronics, optics, geometry, control and environment must all work together.

Field Insight

Engineering & Expert Notes

Size for the Worst Season, Not the Average
Energy

Use conservative solar data and allow for dust, shading and ageing.

Battery Health Decides Autonomy
Batteries

Temperature and cycling reduce capacity. Monitor and plan replacement.

Check the Duty Cycle Assumptions
Sizing

Verify the operating hours and intensity assumed in the energy budget.

Test Control and Wireless Links
Control

Verify range and fallback behaviour in real conditions.

Keep Panels and Optics Clean
Maintenance

Dirt reduces both charging and light output.

Record Performance Over Time
Records

Trend battery and output data to spot degradation.

Precision AGL Academy

Understand SAGL. Build Your Engineering Skills.

You now understand how Solar Airfield Ground Lighting converts photovoltaic energy into reliable aviation visual guidance — from PV and battery sizing to control, photometry, environmental protection and troubleshooting.

Take the next step with Precision AGL Academy.

Learn AGL Step by Step

Build your knowledge through structured technical learning covering:

AGL Fundamentals Components Electrical Systems Design Photometry Testing Troubleshooting Maintenance

Move from understanding how AGL works to developing the practical knowledge needed to analyse, operate and maintain complete AGL systems — grid-powered, portable and solar alike.

Harvest the sun. Store the energy. Control the light. Verify the photometry.