Why are my some of my LED lights flickering?

Question

Something is causing some of my LED lights to flicker in three locations. Here are two examples:

1. https://www.youtube.com/watch?v=4J-g2z_YtYM
2. https://www.youtube.com/watch?v=KlbPdvkZ-BU

There are a few peculiar aspects.

1. The lights flicker sometimes and not at other times. Each time the flicker period is prolonged. I would say the lights flicker about 30-40% of the time.

2. The lights flicker at different "flicker frequencies" as you can see in the videos. The flicker frequency also varies from time to time.

3. There are three different rooms/circuits where the LED lights flicker. (They don't flicker in other rooms/circuits.) In each of the rooms, the light bulbs are of a different brand. There are 4 brands in total: Torchstar, Feit Electric, Hyperikon, Philips.

4. Each of the three rooms uses a different kind of switch: Lutron dimmer (DV-600P), Lutron dimmer (DVW-600PH), and a dumb switch.

5. The flicker sometimes stops if I replace one of the lights on the switch with an incandescent bulb.

6. In one of the rooms, I have two sets of lights on two different switches, on a single circuit. Occasionally one set flickers more than the other.

A bad connection anywhere along the path is out of the question.

Any insight would be greatly appreciated!

Answer 1

Simply put, you have the wrong type of switch for the bulbs you have installed. Most (not in every scenerio) LED bulbs require you to install an ELV type dimmer. What you have installed is a standard incandescent dimmer.

There are three main types of dimming switches. Incandescent, CFL (for incandescents, fluorescents, and SOME LED bulbs), and ELV (for most popular LED bulbs).

If you look on the box that the bulb came in, somewhere in small print it should tell you that A) It's dimmable and B) what type dimming switch it requires.

I could go into detail on exactly why sometimes they flicker and other times they don't but I don't think you'd be that interested in learning the engineering aspects of these switches.

Other causes of flickering:

1) mixed bulb types (ie. incandescent and LED on the same switch)

2) mixed bulb vendors

3) non-dimmable LED bulbs

4) defective LED driver

5) defective dimming switch

Answer 2

I had a flickering problem with under cabinet LEDs. (6411 replacements) But, if I put one or two of the old incandescent bulbs in the circuit, the flickering stopped.

Answer 3

Leds are generally not dimmable, especially the mains ones (110 or 220V). Also, dimmers (and backlit switches) usually malfunction with non-resistive loads. That's why putting in an incandescent bulb sometimes restores more correct operation.

If those are mains leds, try them in a desktop lamp.

If those are 12V leds, you might need to replace the transformer. If you have an "electronic transformer", it has not only maximum rating, but a minimum one as well. In that case replacing 50W bulbs with 2W leds can lead to the power supply being severely underloaded which causes problems. Even if it's an old fashioned toroidal transformer, having too big transformer just wastes energy.

Installations more complicated than a fixture + dumbswitch and running on mains voltage cannot just accept leds in place of incandescent bulbs. You need to have such installation redesigned (and it won't accept regular bulbs then).

Answer 4

I recently had a problem with many LED bulbs on the same circuit causing flickering and bulbs going out. This issue may be due to the power factor of the bulbs. The more bulbs on the circuit, the worse the total power factor. The poor power factor many affect the bulbs themselves.