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ot-led lights blink

cg285

Stainless
Joined
Jan 31, 2007
Location
sumterville, fl
i have made in america outdoor post lights. 120v with photocell. they work fine with a chinese incandescent bulb but they only last about a month. put in leds which work fine except they blink during the day when the photocell is off. google has not been much help so far. i have to believe it is conflicting magic between the led and the photocell. anyone had this issue?
 
I think I replaced the failed photocell in my post lamp maybe 20-25 years ago. Long time ago, I switched from incandescent to cfl bulbs and had no problem other than the bulbs failing at different periods of service, from weeks to years. Then, maybe five years ago, I saw a sale on those newfangled led bulbs and read that they use less juice than cfl, but may not work with old photocells. So, I bought a new photocell and installed the led bulbs. They have been working fine for the five or whatever years, on the old photocell, and I still have that new photocell sitting someplace.

Larry
 
If the lamp is Made in America the best thing to do is contact the manufacturer. They probably have seen something like this before.

My guess? There is some kind of pulsed output from the lamp circuitry that an incandescent won't show because it requires more current to operate and is slower responding than an LED unit. Perhaps the LED bulb you have is not suited for this unit. Is the bulb rated for use with lamp dimmers? Those that are have more robust input circuitry and better resistance to electrical glitches. Some cheap LED bulbs give trouble with anything except a mechanical switch.

Saying the bulbs "blink" is a pretty vague description to provide help with.
 
instead of blink then i will say they come on (individually per lamp)for half a nano second then go off for a full nano second, repeat. they do not interfere with the cells (on the bottom of the lamp)

they are home depot bug compatible chinese made leds bulbs. didn't see anything on the blister pack about photocell. couldn't find any made in usa bulbs. everything is new (3 days ago)
 
Sounds like what happens with an illuminated switch or a dimmer switch on low. Kind of a strobe effect. I have moved some around as some handle the dimmer switch while others do not.
Bill D
 
If the photocell switch was designed to operate a normal incandescent lamp it may have a snubber network across the relay contacts (not much inductance in a lamp but they can have high inrush currents so manufacturers often add a snubber ) . The snubber usually has a small capacitor in series with a resistor. The cap will allow a tiny current through , not enough to cause a problem with a normal bulb , but the leakage​ can slowly​ charge the LED driver's input capacitor until the power supply fires , causing the LED to flash (some types just glow slightly jn the dark).


Bill
 
If the photocell switch was designed to operate a normal incandescent lamp it may have a snubber network across the relay contacts (not much inductance in a lamp but they can have high inrush currents so manufacturers often add a snubber ) . The snubber usually has a small capacitor in series with a resistor. The cap will allow a tiny current through , not enough to cause a problem with a normal bulb , but the leakage​ can slowly​ charge the LED driver's input capacitor until the power supply fires , causing the LED to flash (some types just glow slightly jn the dark).


Bill

that's what sounds like whats happening. now i need to figure out if there are different led bulbs (not much selection for yellow @ the depot) or find compatible cells. the bulbs do say do not use with a dimmer. no reply from the manufacturer
 
"Captain, these light are blinking out of sequence"

"Well, get them to blink in sequence!" :D
 
If the photocell switch was designed to operate a normal incandescent lamp it may have a snubber network across the relay contacts (not much inductance in a lamp but they can have high inrush currents so manufacturers often add a snubber ) . The snubber usually has a small capacitor in series with a resistor. The cap will allow a tiny current through , not enough to cause a problem with a normal bulb , but the leakage​ can slowly​ charge the LED driver's input capacitor until the power supply fires , causing the LED to flash (some types just glow slightly jn the dark).


Bill

Very likely this. LED's only require a small amount of voltage to kick on so a cap. bleeding 2.6 volts is enough to do it.
 
that's what sounds like whats happening. now i need to figure out if there are different led bulbs (not much selection for yellow @ the depot) or find compatible cells. the bulbs do say do not use with a dimmer. no reply from the manufacturer

i just snipped the snubber out of the pir, but you could try adding a bleed resistor across the led ( say 10kohms at 2watt).

Bill
 
I have a pole light with a digital timer switch on it. They also blink when switched off. I've always figured it was leakage across the switching device inside, probably a TRIAC. One standard lamp and it will stop doing this, but the cheap bulbs burn out quickly. The cheap LED have been in there probably 2 years now. I didn't care for the color of the light, and being as cheap as they are I thought outside might be a good place in case they caught fire.
 








 
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