LED House Lights "Flick on"

[Andy Haefner]

Hello, my school recently got a major upgrade and part of that was a transition to LED. Our incandescent house lights were replaced with dimmable LED fixtures. We are faced with a problem however, it seems every time we bring them up at the end of an event (after they have been off for awhile) they have a horrible "flick on" which we can't seem to alleviate, even with an altered dimming curve and a programmed, slow fade up. Does anybody have any tips or strategy's I could try to alleviate this?

 

[Amiers]

Ghost load.
.

 

[derekleffew]

Don't take them all the way to zero.

Do they emit visible light at 1%?

 

[BillConnerFASTC]

Im not sure if you have mains dimming lamps or an actual LED fixture with driver which gets constant power and data. If the former, ghost load is best bet as noted above. If the latter, when a manufacture claims its LED is dimmable, it doesn't mean it dims suitably for performing arts. I test each type before approving, and won't consider if the spec doesn't say dimmable to 0.1% . 1% is not acceptable.

Short of replacing the drivers, not a simple task at all, I know no solutions.

 

[Jay Ashworth]

"Yep, they do that."

This is one of the biggest frustrations I see on here lately; sorry no one told you before you got bit.

Which way you go depends on the answers to the questions asked above...

 

[Andy Haefner]

@derekleffew today I tested them out at low percentages and it seems that they no longer emit visibly at around 4% (still have yet to test that percentage in a true blackout) but I think that method might work for keeping the LEDs powered slightly...

 

[cbrandt]

We've run into this all over the board when trying to help clients with LED transitions. In the architectural/electrical specifier world, 10-100% dimming is the norm, and they have a very hard time understanding why anyone would want something different. It is generally also the lowest cost solution that includes dimming. I can't tell you how many meetings I've been in just to discuss what the word dimming actually means in an entertainment space. As @BillConnerFASTC stated, even a 1-100% dimming has a dramatic and noticeable pop on from zero.

I'm glad to hear you got some good results with bringing them to near zero. I've had to break the news of "it just isn't possible with your system" too many times when I come in after installation is finished.

 

[RickR]

I've also used a staggered start system with non/poor-dimming.

Turn on the smallest most hidden group of lights first. Once they are at 25-50% bring up other groups in sequence. Working from back of house to the stage if no other conditions rule. Much easier with a programmable console

 

[robmerow]

Sorry to hear that... as others have said this is becoming an increasingly common problem for performance venues and movie theaters.

A ghetto solution I've done before is to turn them on to full, and gauge how much less light than that you could live with. If it's 50%, then cover all the houselights with 50% Neutral Density gel. That way the "flick on" is only half as bright.

I've done this in an auditorium with dimmable fluorescent linear houselights. Perfect? Not by any means.