What kind of dimmer can be used for LED lights?

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ResiMan

ResiMan

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I have installed some LED cabinet lighting for a customer who now wants to dim them. He installed a regular dimmer switch, which is not working. Any suggestions?

p.s. The cabinet lights are a Generally used Electric brand. ;)
 
I seem to remember if it is dimable then a standard dimmer works, but I would check with the manufacturer rather than trust my brain. It appears dimming LED is not a good idea and will shorten lamp life.
 
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I don't know all the details, but just yesterday I was talking to a sales guy about this. He was saying that there is a special low VA dimmer module needed that can handle the low loads (down to 2-3 watts) that you run across with LED drivers. His comment was that you don't see them often because the price for a dimming module can run around $250-$300 and are special order items with a long lead time. IIRC they're made by Lutron.

Correction: I just found a Leviton "Lumiled" dimmer for about $75 plus a dimming module for about $56 from one source. I don't know that they work with all types of LEDs though.

Scroll down to the product list:

http://www.intl-lighttech.com/products/light-source/led-modules/undercabinetlighting
 
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LEDs need to be dimmed with a PWM dimmer, so the answer to the question is "A dimmer designed specificallyto dim LEDs".

This dimmer is a DC animal, so the puck lights need to be wired up for DC, generally in series chains.

I dont know of any commercially available cheap LED dimmers; only several hundred bucks type stuff. Not really intended for installation in a home on a wall plate with a knob on the front, more architectual installations with eye-watering fitup costs. Thats not to say someone doesn't make a reasonably priced dimmer, just I've not seen one.
 
I have successfully used the Lutron Skylark SELV model (electronic low voltage) on a Cree LED install and a Renaissance lighting LED install. Both manufacturers recommended the same model number. They are about $55 - $70 each.
 
Lutron makes dimmers that are compatible with certain mfgs.

For those of you who don't know what PWM is: it is just short for Pulse Width Modulation. Behind the fancy name is a digitally encoded light output control. It regulates the cyclical peaks and lows of power - called duty cycle - released to your LEDs via a special program often hard-coded in a device called controller.
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Lutron states that you have to match the manufacturer with the dimmer. Basically if the manufacturer is not on their list they do not guarantee their product to work.

LED Rope lighting may work well with standard dimmers but it's better to know the mfg. and match the dimmer to the product. This is all from Lutron Tech Support.
 
Not sure about the bulbs they are pushing right now as an incandescent replacement but low voltage led systems can typically be installed with a dimmer driver in the mix. Those drivers will typically require a 0-10V dc dimmer.
I know Jesco sells you the nova T dimmer with their stuff, but they will also admit that a 0-10V dimmer made by watt-stopper will work as well and it's less expensive. But when you add the dimmer driver and the dimmer to the mix your still looking at 150-200 bucks...
 
I had one set of LED lights that had 3 volt regulator chips powering the leds, guess what, trying to dim them didn't work, because the regulators would just readjust the voltage to 3 volts, so there are some that are not made to dim.
 
I have LED lights in my office on a basic Leviton dimmer. Works pretty well, but not perfect. The LED manufacturer has a list of approved dimmers but they are all pretty expensive so I went with a basic unit. The only complaint I have with it that the lights are off and I want them dim I need to crank them up to get them on and then back down. Not a big deal once you get used to it.

Proper LED dimmers are available in constant voltage (PWM) and constant current reduction types. Best check with the LED vendor for their list of approved products.
I am regularly specifying internal LED lighting with (approved) dimmers with good results.
 
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ResiMan said:
I have installed some LED cabinet lighting for a customer who now wants to dim them. He installed a regular dimmer switch, which is not working. Any suggestions?

p.s. The cabinet lights are a Generally used Electric brand. ;)
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Find out if the LED driver is rated for dimming, if it is not and you dim it anyway it may or may not function properly, and you will shorten the life of the driver assembly. In any case you will have better success with a dimmer rated for electronic low voltage loads.

I just completed a landscape lighting project with two different LED fixture types, one type for path lighting and the other for up lighting. Manufacturer was KIM.

The path light LED drivers were not rated for dimming, the up lights were.

We used a Lutron Maestro dimmer for the up lights, worked like a champ.

One problem you will run into is meeting the minimum load requirements on an ELV dimmer. LED fixtures are usually 5 to 10 watts, the minimum load requirement for reliable operation of an ELV dimmer is about 20 watts. You may have to use a dummy load (sold by Lutron) to make it work, but that defeats most of the reasons for using a LED in the first place.
 
Well we agree on the dc power source led s run on dc so you would need like the above a dc pwm power source .

A led can dim by freq change and pwm meaning the wave can be a square wave and you adjust the pulses you can do this but it must be dc output .

Pulses can be spaced out or the modulation of pulses can be adjusted time varying .

If all the leds are in series a ac dimmer will work because they are diodes but to design it you would have to run separate strings because the current would be lost in one large series string and they would be very dim thats why it doesnt work .

Small strings in series but you better know the total current that will flow thur the smaller strings or you can blow them all out in one second used a resistor with strings .

You can buy a pwm dc motor controller at any electronics web site and you can install it in a switch box just like a dimmer.
 
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