Flickering LED lights

[Dave Cav]

Our new house is 100% LED. Most of the room lights are can light "conversion" where they installed 6" can lights with an intregrated LED trim ring. They are 75w equivalent CE units from HD. At full brightness they work fine. However, when dimmed down I get a tiny but noticeable amount of flicker. It's almost invisible, but in a smaller room like the office, it's very annoying. I'm actually thinking of replacing some or all of the LEDs in the office with regular incandescent reflector floods or find a much lower output LED.

The light fixtures are dimmer rated and recommend Lutron dimmers which I'm using. The dimming function works fine; they dim from about 20% to full brilliance, but the low level flicker is a real problem. Any ideas or suggestions?

[Ken Fitzgerald]

I'd reach out to the customer service department of the LEDs for suggestions.

[Jim Koepke]

My experience with dimmers is likely out of date. My first experience was with one my father installed in the 1960s. It was a Hi-Lo switch in our restroom. It flickered since it was a diode in series with the lamp on the Low setting. This cut off half the wave of the AC current.

More modern dimmers work with a SCR or Triac. These tend to turn on the device at a controlled point along the sine wave and then off at zero crossing. My understanding is some people can detect this and some can not. These types of dimmers do not vary the voltage, they vary the amount of the sine wave. It is similar to Pulse Width Modulation used in DC circuits for the same effect. If you have a variable output LED flashlight, set it on low while out in the rain and you may see the drops of rain making dashes in front of the flashlight. You may also be able to just swing the flashlight in hand and notice the dashes of light as it passes at the edge of your vision.

Another problem is LEDs do not always draw enough current to keep the switch's electronics on, causing a misfire which is seen as flicker.

Google > why led flickers on dimmer < to find a lot of various takes on the problem.

jtk

[Kev Williams]

Just from personal experience, I'm finding these claims of 10 years to 45 years of LED service life to be complete BS. I haven't bought a lot of LED lights but at this point I'm glad, because I've scrapped several of them- a magnifying glass fixture, 2 of 12 GU10's in some track lighting, and about 4 out of 10 LED 'standard' bulbs. Most started doing the 'flicker' thing; In my case they start flickering for a bit before coming on, then the "a bit" becomes several seconds, then minutes, then infinity. The GU10's just stopped working at about 18 months old. The magnifying glass lights lasted about 3 years, the bulbs are around 1 year old. I was getting more life than that out CFL bulbs.

I have no problem changing out bulbs, unless they cost 9x as much as the ones I replaced...

[John K Jordan]

This was discussed recently, maybe in another forum, can't remember. The LED emitters themselves can certainly last a long time (unless overheated). However the complex electronic circuitry needed to drive the LED emitters from 120v power is what fails. The flickering then death is a typical experience.

After a few bad experiences I've quit buying fixtures with integral LED emitters. I do buy LED bulbs with the electronics built into the base so when they die I can replace the bulb.

JKJ


Just from personal experience, I'm finding these claims of 10 years to 45 years of LED service life to be complete BS. I haven't bought a lot of LED lights but at this point I'm glad, because I've scrapped several of them- a magnifying glass fixture, 2 of 12 GU10's in some track lighting, and about 4 out of 10 LED 'standard' bulbs. Most started doing the 'flicker' thing; In my case they start flickering for a bit before coming on, then the "a bit" becomes several seconds, then minutes, then infinity. The GU10's just stopped working at about 18 months old. The magnifying glass lights lasted about 3 years, the bulbs are around 1 year old. I was getting more life than that out CFL bulbs.

I have no problem changing out bulbs, unless they cost 9x as much as the ones I replaced...

[Wade Lippman]

Can't answer your question, but have one....
I have seen the trim rings for sale; but why buy those rather than using LED bulbs in your existing fixtures?

[Matt Marsh]

Certain models of LED dimmers have an adjustable bottom threshold, where you adjust the light level to a point just above where they flicker, then set that as the bottom dimmer setting.

[Matt Marsh]

This is an example of one that has the adjustment.

[Jim Koepke]

With Matt's post it may be the suggestion to use a Lutron dimmer might actually mean to use a specific Lutron dimmer. Lutron is surely making more than one model of dimmer.

jtk

[Jim Koepke]

So far we have had 4 LED lamps fail. 3 died and one started to flicker. They were replaced at no cost to us by the maker. We only needed the code from the packaging, which we had saved just in case. Most of the others have done well and we switched to LEDs about 8 years ago. Other than a string of outdoor lights only a few lamps are still incandescent or CFL. My shop has some T-5 fluorescent, but they will be replaced with LED fixtures over time.

jtk

[Matt Marsh]

With Matt's post it may be the suggestion to use a Lutron dimmer might actually mean to use a specific Lutron dimmer. Lutron is surely making more than one model of dimmer.

jtk

Yes, Lutron makes several LED compatible dimmer models. Only a few have the adjustable threshold. Another thing to add, is that if your LEDs are flickering, it will drastically decrease their lifespan.

[Matt Marsh]

So far we have had 4 LED lamps fail. 3 died and one started to flicker. They were replaced at no cost to us by the maker. We only needed the code from the packaging, which we had saved just in case. Most of the others have done well and we switched to LEDs about 8 years ago. Other than a string of outdoor lights only a few lamps are still incandescent or CFL. My shop has some T-5 fluorescent, but they will be replaced with LED fixtures over time.

jtk

For the past 10 years or so, retrofitting old technology lighting with LED, has made up the largest part of my job here at the University where I work. We now literally have thousands of LED lights here on campus, ranging from type A tubes, flat panels, and just screw-in lamps. We have had many many failures, but it is not near the rate that we had with ballasts and bulbs of other types. Out of all of the failures, only one was a catastrophic one, were the bulb literally blew apart from its base.
It also destroyed the dimmer, and the socket.

[Steve Peterson]

It may or may not help the OP, but I had a flicker problem with 4 LED bulbs on a particular dimmer. 3 bulbs were perfectly fine, but adding a 4th bulb would cause them to flicker.

All of the zones had 4 lights, so I would either take out one bulb or replace one of the bulbs with incandescent.

Steve

[Dave Cav]

Can't answer your question, but have one....
I have seen the trim rings for sale; but why buy those rather than using LED bulbs in your existing fixtures?

I think that's what I'm going to end up doing in the office, so I can try various size bulbs with no dimmer to find out what works best in that situation.

[Dave Cav]

Yes, Lutron makes several LED compatible dimmer models. Only a few have the adjustable threshold. Another thing to add, is that if your LEDs are flickering, it will drastically decrease their lifespan.

Yes, my Lutron dimmers have the adjustable threshold and I have tinkered with it to no avail. The flickering is very subtle and is caused, I believe, by the way the dimmer switch cuts off the sine waveform of the voltage. I may try another style of Lutron dimmer to see if it makes any difference but I think I'll eventually retrofit the cans for screw in lamps and experiment with bulb size and lumen output to eliminate the dimmer in this location.

We have about 3 dozen of the Home Depot Commercial Electric 75w equivalent trim ring fixtures in the house and so far in about a month, two have failed so far. The failure mode is that they heat up and then begin strobing, then go out. Over all I'm pretty disappointed in the performance of these lights.

[Matt Marsh]

We have about 3 dozen of the Home Depot Commercial Electric 75w equivalent trim ring fixtures in the house and so far in about a month, two have failed so far. The failure mode is that they heat up and then begin strobing, then go out. Over all I'm pretty disappointed in the performance of these lights.

I'd be willing to bet that the drivers in these fixtures are the problem.

[Bob Grier]

Try doing what Steve P suggested - replace one bulb in the circuit with an incandescent bulb of equivalent lumens and color. That is what I did to curtail strobing in my 12 can light circuit in the kitchen. I tried adjusting the limit dimmer, moving the dimmer to a different location in the circuit (3-way), and even replacing the dimmer. Only thing that worked was installing an incandescent bulb in the circuit.

I have strip LEDs under the upper kitchen cabinets and they flicker sometimes at different dimmer settings or for no apparent reason. I can not so easily install an incandescent bulb in that circuit to stabilize the sensing. I suspect that the flicker is because of other circuits tied to the same breaker circuit but the flicker can usually be stopped by changing the amount of dimming.

[Chris Padilla]

Most of the control out there for LEDs to get dimming or fading (to start or stop) or flashing is via PWM--Pulse Width Modulation. You can Google and learn a little bit about it if you like.

[Jim Koepke]

replace one bulb in the circuit with an incandescent bulb of equivalent lumens and color.


Another problem is LEDs do not always draw enough current to keep the switch's electronics on, causing a misfire which is seen as flicker.


Out of all of the failures, only one was a catastrophic one, were the bulb literally blew apart from its base.

An incident of mine with a mis-wired capacitor blowing up in the very early hours still gives me cause to chuckle at times.

This makes me wonder if it could have been a capacitor that blew up in Matt's case. It may be the feedback from the capacitance of the LED lamps is tricking the switch's electronics into seeing no load for an instant or two, causing a failure to turn on, thus the flicker. The incandescent bulb provides a constant load thus no tricks to the switch's circuitry.

jtk

[Dave Cav]

I did try adding an incandescent bulb in the circuit earlier and it didn't make any difference, plus there's no mounting plate in the recessed cans to hang a PAR lamp from.

I have made progress. Home Depot had the 65 watt LED trims on clearance so I got two boxes of four and installed four in the office replacing the 75 watt (equivalent) trims. Little to no flickering now, so apparently the driver in the lower wattage lamps works better with the Lutron dimmer I have. I also got a Lutron Maestro dimmer which I'll try out tomorrow. The 65 watt trims are more appropriate for the smaller room and relatively low ceiling as well.