New kitchen has Electronic Low Voltage lighting. Can I use my Zwave Dimmers?

[lazarustx]

We are almost done with the kitchen remodel. Yay on that. The General Contractor is annoyed with my "smart switches" since he thinks they are cause of problems with the LED cabinet lighting. Turns out they ordered a non dimmable kits so the new dimmable kits are installed and working.

The new dining room light and pendent lighting need to be ordered. These are on my dime.
The specs on all the items we are looking at show that they are ELV and having dimming capabilities but in multiple cases I've seen reference to a separate $$ dimmer.

Does anyone have experience with using their Zwave dimmers to handle these new LED lights that are labeled as ELV's?

Maybe I don't have all the terms down correctly. So ask away.
Regards,
Rodney

[TC1]

ELVs are a problem in modern smart lighting.

When I had to remodel my kitchen, I made sure to purchase a true magnetic low-voltage (MLV) system. This consisted of a lighting rail system for the light fixtures and a magnetic 120-to-12VAC transformer that gets hidden in an upper cabinet. This pretty much ensures that dimming will be smooth no matter what the light load looks like (incandescent, halogen, LED) and what the dimmer is controlling the input to the transformer.

In my office, I'm limited for space so I went with a lighting rail system that had an electronic low-voltage "transformer" built into the center of the fixture that mounts to the junction box in the ceiling. These are not true transformers, but really electronic step-down circuits from 120VAC that comes from your light switch to 12VAC for the bulbs. With the original incandescent bulbs that came with the kit everything dims fine, even with a smart dimmer in the wall. But as soon as you try to use a MR16 LED bulb... all hell breaks loose.

Ther problem is this:
1. Your electronic smart dimmer has to chop the AC waveform in order to reduce power going to the load. It does it so quickly that your eye doesn't notice it.
2. The ELV circuit in the fixture is chopping up the waveform again in order to reduce the normal 120VAC down to 12VAC that a normal bulb would expect. (A true magnetic transformer simply reduces the waveform proportionally and doesn't chop it).
3. The circuit inside a LED bulb then has to convert AC coming into it to DC to power the LEDs in the bulb.

So in the end, three different points in your circuit have mangled the voltage powering the light. And because there's two different ways to chop the waveform (leading edge vs trailing edge) in the dimmer, ELV transformer, and finally the LED bulbs, there is no guarantee all these components will work well together. Also, many ELV transformers need a minimum load to operate properly, so when switching to LEDS from halogen, there's an issue.

That being said... if the ELV fixture you buy is specially designed for LED bulbs, then there's a good chance everything will work ok. My problem is that I went from halogen to LEDs later on.

It also depends on the dimmer you use, some use trailing edge dimming and some use leading edge dimming. You need to find out what your lighting prefers, and then see if your dimmer supports it.

Sorry to be long winded, but I've researched this issue extensively... much to my dismay, lol.