If lights in the parking lot of a commercial property are still bright during the day, you might have a lighting control problem. Needless daytime running can result in higher energy usage, reduced fixture life and higher electric bills.
In many instances, the LED fixture isn't the issue. This can be caused by the settings or installation of the photocell (dusk-to-dawn sensor) as well as the control configuration.
This troubleshooting guide covers how photocells work, why lights might remain on during daylight hours in a parking lot and how to ensure automatic dusk-to-dawn operation is enabled and/or checked.
How Does a Photocell Work on Parking Lot Lights?
A photocell (also known as a dusk-to-dawn sensor) is a device that automatically regulates outdoor lighting, depending on the level of ambient light.
As ambient light falls to a lower level than the photocell needs, at night, the fixture will turn on the lights. Upon the return of daylight, the sensor captures enough light, and turns the lights off.
Photocell operation is often added as an option to the modern commercial LED parking lot lighting system so it can be used in a variety of applications. Users can select manual operation, external controls or automatic dusk to dawn lighting.
Common Reasons Why Parking Lot Lights Stay On During the Day
If the parking lot lights don't turn off during the day, consider the following:
Cause 1: Photocell Function Is Not Activated
Several LED parking lot lights come with an optional photocell. If the photocell opening does not need the automatic dusk to dawn, the photocell opening can be left covered.
If the fixture has an optional photocell sensor:
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The black cap cover will prevent the photocell function from operating.
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The built-in dusk-to-dawn photocell sensor is activated when the black cap cover is removed.
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Once energised, the fixture will automatically adjust to surrounding light.
If the lights are working normally but won't turn off during the day, check to see if the photocell function has been enabled.
Cause 2: Photocell Sensor Is Blocked or Dirty
Photocells use ambient light to be detected. Dirt, dust, bird feces, leaves or other clogging material will diminish the amount of light reaching the sensor.
If the light is not getting enough light, the sensor might think it is nighttime and continue to power on the light.
Check the following:
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Use soft cloth to clean photocell lens.
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Remove any objects blocking direct exposure to daylight.
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Make sure other buildings or plants near the building are not casting too much shade.
Cause 3: Incorrect Installation Location or Orientation
Photocell sensors require proper exposure to ambient light in order to function properly.
Avoid installing fixtures where the photocell is:
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Surrounded by buildings.
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Strong lights from manmade sources.
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Planted in spots where there is shade 24/7.
If the sensor is not properly installed, it can sense the wrong amount of light and may cause the ON/OFF response to be delayed.
Cause 4: External Lighting Controls Override the Photocell
Commercial properties may utilize a number of lighting control techniques, such as:
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Timers
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Central lighting controllers
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Motion sensors
In the case of an external control system, it can take over the function of the photocell and maintain lights on at a preprogrammed time.
Review your control settings to see if there's another system controlling the fixture.
Step-by-Step Troubleshooting Guide
If replacement is going to be required, perform a few simple checks to determine the cause.
Step 1: Confirm Photocell Activation
Action:
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Always switch off electricity prior to inspection.
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Ensure black cap cover is in place over top of photocell opening.
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If automatic Dusk-to-Dawn operation is desired, remove the black night cap.
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Reconnect power and check the functioning of the fixture.
Result:
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If the light starts to react to light conditions, then the photocell was just switched off.
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If the light is still on, keep on trouble shooting.
Step 2: Clean and Inspect the Photocell Area
Action:
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Shut off electricity at the circuit breaker box.
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Check the sensor region for dust, dampness, cracks or damage.
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Thoroughly clean the surface of the photocell.
Result:
If the fixture turns off after cleaning, it may have been a problem with the fixture blocking the sensor's ability to detect daylight.
Step 3: Perform a Daylight Simulation Test
To test if the photocell is working:
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Find the photocell sensor.
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Completely cover the sensor (like at night).
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Take off the lid and set it in bright light.
A short response delay may be required when considering the fixture design to avoid switching unwanted lights due to temporary light changes.
How to Properly Use the Optional Dusk-to-Dawn Photocell Feature
For commercial LED parking lot lights, with an option for photovoltaic cells:
If automatic lighting control is required:
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Remove the black cap cover.
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Ensure that the photocell sensor can see light from the surrounding area.
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Let the sensor do the automatic control of ON/OFF switching.
In case of any other forms of control:
Keep the photocell sensor blocked, and go for other means of control like:
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Building automation systems (BAS)
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Timers
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Smart lighting controllers
Thus, a variety of choices for lighting control options is provided to the users.
Benefits of Using an Automatic Photocell on LED Parking Lot Lights
A correctly set-up dusk-to-dawn photocell offers the following benefits:
Energy Savings:
The light switch will only work at night, thus no energy will be consumed during the day.
Less Maintenance:
Since everything works automatically, the maintenance is minimized and the useful life of LED fixtures increases.
Convenience:
No manual operation is required. Lighting adjusts itself according to the natural daylight.
Versatile Installation Possibilities:
Thanks to the optional photocell function, people can set their own conditions for lighting control depending on commercial environment.
Conclusion
In case your parking lot lights stay on during the daytime, the problem may not be related to fixture failure. First of all, check if the optional photocell function is turned on, whether the sensing area is dirty, and whether there are some external influences on its operation.
Demilare LED parking lot lights include the option of dusk-to-dawn photocell function which makes it possible to turn on automatic control of lights in case you need it. All you have to do is to take off the black cover and the sensor is ready for use.
Check out the whole collection of commercial LED parking lot lights with optional dusk-to-dawn photocell function.![]()