| 1 | LED and luminaire efficacy | Compare luminaire output in lumens with input power in watts. Do not treat LED-chip efficacy as the efficacy of the complete light fixture. | A 6,000-lumen luminaire drawing 40 W has a calculated luminaire efficacy of 150 lm/W (6,000 ÷ 40). | Request the test report and confirm that both the lumen output and power refer to the same complete luminaire and operating condition. Treat efficacy targets as screening criteria, not proof of lighting quality. |
| 2 | LM-80 lumen-maintenance evidence | Review LM-80 test data for the LED light source, including test duration, drive current, case temperature, and the tested source identification. | LM-80 reports measured lumen-maintenance data for solid-state light sources over the stated test period; 6,000 and 10,000 hours are examples of test durations, not product lifetime ratings. | Check that the tested source and operating conditions are relevant to the proposed luminaire. LM-80 data alone does not establish the lifetime of the complete street light. |
| 3 | TM-21 projections | When a lifetime projection is provided, check the TM-21 method, the underlying LM-80 data, and the reported projection limits. | TM-21 uses LM-80 data to project LED-source lumen maintenance; a projected value is not the same as a directly measured result or a warranty for the whole luminaire. | Ask for the supporting LM-80 report and clearly labeled projection. Do not compare projections as if they were measured hours of complete-fixture operation. |
| 4 | Illuminance and light distribution | Compare photometric files and a project-specific lighting calculation, not lumens alone. Road width, pole spacing, mounting height, and the required lighting class affect the result. | Two fixtures with the same lumen output can produce different roadway illuminance and uniformity because their optics distribute light differently. | Request an IES or equivalent photometric file and verify the design against the applicable road-lighting requirements for the project. |
| 5 | Daily energy budget | Calculate the light’s daily energy use from its actual power profile and operating hours, including any dimming schedule. | A 30 W load operating for 12 hours uses 360 Wh per night before accounting for controller and conversion losses (30 W × 12 h). | Compare energy demand with expected solar harvest and usable battery energy. Ask for the assumptions behind the stated autonomy. |
| 6 | Solar-panel sizing | Assess panel wattage against local peak-sun-hour data, seasonal conditions, shading, and system losses. | Illustrative estimate: a 100 W panel at 4 peak sun hours per day with an assumed 75% net system factor yields about 300 Wh/day (100 × 4 × 0.75). | Compare the estimate with the nightly energy budget. This example is not a site forecast; use local solar data and the project’s worst-season design conditions. |
| 7 | Battery capacity and autonomy | Compare nominal watt-hours, battery chemistry, allowable depth of discharge, temperature limits, and the energy reserved for cloudy periods. | A 12.8 V, 50 Ah battery has 640 Wh of nominal energy (12.8 × 50); usable energy is lower and depends on the battery and system design. | Request usable-capacity and autonomy calculations, including operating temperature and reserve assumptions. Do not equate nominal watt-hours with usable watt-hours. |
| 8 | Controls and dimming profile | Check whether the controller supports the required dusk-to-dawn operation, dimming schedule, low-voltage protection, and recovery after poor solar days. | A documented schedule that reduces output during lower-traffic hours can lower nightly energy demand, provided the required lighting levels are maintained. | Request the control settings and calculate energy use for the full programmed schedule, rather than assuming the fixture runs at one constant wattage. |
| 9 | Ingress protection and environment | Check the stated IP rating for the relevant enclosure and the product’s documented temperature, corrosion, wind, and installation limits. | IP ratings describe protection against access, solid objects, and water under defined test conditions; they do not by themselves establish resistance to corrosion or every outdoor hazard. | Confirm which components the rating covers and review test documentation. Match environmental requirements to the actual site conditions. |
| 10 | Warranty, replaceability, and service | Compare warranty coverage and exclusions for the luminaire, battery, panel, and controller, along with replacement-part availability. | Battery service life and warranty terms may differ from those for the LED light source or fixture; review each component separately. | Request written warranty terms, maintenance instructions, and a parts-replacement plan. Confirm who handles service and how failures are reported. |