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Greetings everyone.

I have an issue that I can't seem to find an explanation for anywhere. I've looked all over the net, and all over this forum and can't locate a similar concern. Here it is:

I have a 2 socket motion detector outdoor fixture on my garage, works great but the bulbs burned out. Bought 9 watt led bulbs, and I went about a year with perfect operation, and then one started flickering. Replaced it, and a month later, the other started flickering. bought 12W led outdoor flood bulbs to replace both, and no light. No flicker, no hum.. No attempt at illumination.

They won't come on if LED bulbs are in both sockets of the fixture.. However, if I swap one of the bulbs for an incandescent or a CFL, they will both come on when the sensor is triggered. Two CFL's will work perfectly, two incandescent's will work perfectly, but not 2 LED's. Perplexing...

all of the bulbs (LED, CFL, INC) will work in other fixtures in the house, but if I pair 2 led's in the motion sensor, I get nothing except the red LED on the sensor indicating that the sensor is detecting. It's very strange. I've kicked the breaker off for 10 minutes and tried again, - nothing. (all done at night when the photocell was working its magic.)

For now, I have 1 LED in the high traffic direction, and a bright CFL in the direction of the path less traveled, and it works fine. I would just like to know if anyone has had a similar issue, or if anyone can explain this phenomenon. I am slowly working towards all LED's in my home, and would like to understand the science behind why this combination does not work.

Any help from the experts and the experienced would be greatly appreciated.
-and it is nice to meet you all!
 

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Put halogen or CFL in it. You probably won't notice the difference in your utility bill. Or buy a new integrated LED fixture replacement. I don't trust LED drop ins and can't wait for the next generation of incandescent.
 

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I have a similar issue, although...


In one outside fixture with a motion sensor, both bulbs light up as they should.

But, in a second fixture, one bulb is very dim and one is bright.



LED bulbs are really a different breed. Some will work just fine, some will not. Some will work with most dimmers, and some will not. It's all caused by the electronics that are in the bulb, and some aren't made quite as well.

Bottom line? It's a crap shoot.


Solution? Use one LED and one standard bulb in the existing fixture, or purchase a new LED fixture.
 

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Some of those fixtures run a trickle current through the lamps to operate the sensor. That would explain your flickering LED. Could also explain the non function if the lamp doesn't pass enough current.
 

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I have a 2 socket motion detector outdoor fixture on my garage, works great but the bulbs burned out. Bought 9 watt led bulbs, and I went about a year with perfect operation, and then one started flickering. Replaced it, and a month later, the other started flickering. bought 12W led outdoor flood bulbs to replace both, and no light. No flicker, no hum.. No attempt at illumination.
Some of those fixtures run a trickle current through the lamps to operate the sensor. That would explain your flickering LED. Could also explain the non function if the lamp doesn't pass enough current.
I surmise that your PIR Sensor switches its "load" using a Triac.
The triac needs to "see" a small voltage at the start of each half cycle for it to start conducting. With a resistive load, such as an incandescent lamp, this voltage is available.

However, LEDs and CFLs (usually) do not operate directly on the 120 V AC supply. They usually incorporate a "Switch Mode" power supply, the first stage of which is a "Bridge" rectifier charging a capacitor. The triac in the PIR Sensor does not "see" sufficient voltage through this "load" to start conducting.
While the initial 9 W LEDs "worked", this may have been due to the fact that the power supply in these was not a "straight" Switch-Mode supply but incorporated some form of resistive "shunt" (?) As you have since found, other (most) LEDs do not work with this PIR sensor.

However, not all PIR Sensors use a triac directly to "switch" the "load".
Some incorporate a relay and this will (of course) switch LEDs and CFLs.

Since your PIR sensor is a two socket device, it may be that it is rated only to drive 2 150 W incandescent "parafloods" (300 W total). PIR sensors not attached to lights are often rated to higher wattages and it is likely that these would incorporate a relay.

It seems that PIR sensor manufactures do not advise if a relay is incorporated in their products. However, they should state if their product will operate LEDs (since these are now becoming available) and, particularly, they should state if they will NOT.
 

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Frodo makes great synopsis of LEDS. On the consumer level it's simple, don't trust drop in LED'S to perform as you expect unless the switch controlling them is binary. This is why I suggest getting a new fixture or put in bulbs that are known to work.
 

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It seems that PIR sensor manufactures do not advise if a relay is incorporated in their products. However, they should state if their product will operate LEDs (since these are now becoming available) and, particularly, they should state if they will NOT.
After writing the above I checked some of these items at my local DIY store.

One manufacturer stated that the PIR sensor would control up to 1000 W of Incandescent lamps or 450 W of LEDs/CFLs.
Another manufacturer had two identical looking models (with only one digit different in the "Model Number".) However, one of these was $4 dearer and was marked "Suitable for LEDs and CFLs".
 
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