A lot of lights use photocell technology to operate.
A photocell sensor is a device that uses the ambient light level to control the circuit. Simply – it turns lights on when the sun goes down.
You might have a photocell sensor at home already. Street lamps use them too. But do you need a special photocell for LED lights, now that those light bulbs are becoming much more popular?
LED lights do need special photocell sensors that are compatible with LED light fixtures. Older photocells reduce the current in a way that’s incompatible with LED lights, causing them to dim, flicker, and burn out much faster than they should.
In this guide, I’m going to take you through:
- The difference between LED photocells and regular photocells
- Troubleshooting when your LED light flickers on a photocell circuit
- How to choose a compatible LED photocell sensor
LED Photocell vs Regular Photocell: What’s The Difference?
The difference between LED photocells and standard photocells is how the current is managed. LED-compatible photocells direct the current away from your outdoor light fixtures, so that the bulbs won’t flicker and burn out.
Photocell for LED Lights
A photocell for LED lights works differently to other types of photocell sensor because it doesn’t allow the low current to flow to the fixture. When the resistance changes, it completely diverts the current, so LED lighting doesn’t switch on.
LED lighting is different from older lights, in that it is designed to work on a lower voltage. So, when used with a non-compatible photocell, the current provided even when it’s daylight is still sufficient to light up the bulb.
And yet, because it’s inconsistent, the bulb will also struggle to work properly too. LED lights work very unusually on an incompatible photocell sensor and may flicker, or work but very dimly even at night.
They’ll also suffer dramatically from a lower lifespan – the bulbs will burn out because they’re being damaged.
None of this is a concern with a photocell sensor for LED lights. Your LEDs will work properly and last as long as they would on a regular circuit.
It’s also worth noting that a photocell sensor compatible with LED lights will work with all other light types too. They aren’t explicitly designed for LEDs only.
Regular Photocell
Regular photocells were designed to be used with a traditional light source such as an incandescent or halogen bulb, or a light with a ballast.
The ambient light causes a change in the resistor, which then impacts the current. As the ambient light increases, a lower current is sent to your outdoor fixtures, and that level of power isn’t enough to make the bulbs turn on.
Then as it gets dark, the resistance changes again, the higher current is sent through the circuit, and the light fixtures are fully powered.
My Photocell LED Light Flickers: Troubleshooting
LED light fixtures flickering on a photocell circuit could be caused by:
- An incompatible photocell
- A photocell that is too sensitive to minor light changes
- Loose wiring
- Overloaded circuits
If you’re not using an LED-compatible sensor then it will likely cause flickering in your lights.
It could also be that your photocell is just too sensitive, and is adjusting to changes in the ambient lighting. This will tend to cause flickering at dusk or dawn more. But try changing the calibration of the sensor, as that may work.
Otherwise, it could be a problem unrelated to the way the photocell works. It could be loose wiring somewhere on the circuit, causing an inconsistent connection.
Or you might’ve overloaded the circuit with too many bulbs, meaning there’s not enough power to get them to work properly.
Check for loose wiring first, but if you can’t find any problems and you know the sensor you’ve chosen is working correctly, try removing some bulbs to see if that fixes it.
If it does, you’ll need to rewire the circuit to provide more power. Alternatively, you may need a second photocell to control some of the lights on the new separate circuit.
Selecting An LED Compatible Photocell
Choosing a LED rated photocell is relatively simple – you just need to check the packaging or the online description to make sure it mentions LED lighting.
There’ll usually be a section titled “Rated For” although it might just explicitly state a list of compatible lighting types.
Despite LED lights working on a lower voltage, you typically don’t need to worry about the voltage of the photocell sensor – the LED light will have a driver stepping the voltage down at the light fixture.
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The only difference would be when you’re installing garden lights that need a transformer. These step the voltage down much earlier in the circuit.
For these, it’s easiest to just buy a transformer with a photocell built in.
Final Words
And there you have it – everything you need to know about how LED lights work with a photocell sensor, and how to make sure your outdoor fixtures are behaving as they should be when you want them to switch on and off at dusk and dawn.
If you have an existing photocell sensor installed in your home, and you’re not sure whether it’s suitable for LEDs, just check the sensor for a model code, and look it up online. You should be able to find the information quite easily.
If not, it’s probably a really old sensor and for the sake of a few bucks, it might be worth replacing it with one you know is compatible with LEDs.
And if you have problems with your other landscape lights flickering outside your home, check my guide on how to resolve those issues too.
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