HID LED retrofit options

NickVon

Well-Known Member
Investigating options for HID > LED replacements bypassing ballasts (Direct wire)

We have 12 Metal Halide lights in our auditorium theater space. about 40' that cover the audience seating.
They are primary use as "work lights" or general lights when a show or event is not happening. Things like Faculty meetings, show/event load ins, rehearsals, me generally being the space and futzing around. They are the daily use lighting for the room. House lights are controlled by our LX console and not wired into any sort of unison system, and generally aren't bright enough to facilitate much more then pretty warm light for pre/post show.

The (12) 400w Metal Halide fixtures. that each have (2) 50lb Ballasts that are all in varying states of fine to failure, are just becoming to much to maintain. The building is currently closed for some historical roof repair and myself and physical plant decided now is a good time to think about relatively easy alternatives.

Obviously LED was the initially investigation choice. We purchased and tested one GE 150w 20,0000lm
and the initial results where great, but completely unusable. It was noticeably loud. I guess I didn't think they these sort of units would have fans in then, I was foolishly thinking sold heat-sinks, as a fan would seem to be a component that could fail long before the LED's rated life of 20k hours.

Most inventory I've seen don't specify if any of these retrofits are Fanless Heatsink or have a operational decible rating.

With just the one installed it was a noticeable somewhat high pitch fan whine from 40 ft away. I can't imagine hat 12 of them installed would produce. Unscientifically on my SPLnFFT iphone app it raised the room 5db from 38db to 43db, with just the one.

I spoke to someone at 1000bulbs.com and they suggested a fixture replacement to this https://www.1000bulbs.com/product/201300/PLT-10941.html It seems to have all the guts above the ceiling would I think would certainly make for less noise.

Any other options or thoughts out there. We don't need a direct 400w 20,000 lumen replacement as if we get them all the LED it'll be the first time they all work together anyways. But we definitely need something in that world of output for the distance and coverage.
 
Two types of high power LED fixtures: Those that use a fan, and those that use the whole fixture back as a giant heat-sink. Needless to say, the second type do not make a fan noise. Although the march towards LED is strong, there are some problems showing up. Even though most have a 50,000 hour life, many suffer an earlier failure in one of two areas- The first is fixtures that use long-chains of series elements. Any element failure will take out the whole chain and reduce the fixture output. The second is failures in the electronics. The emitters may be rated at 20 years, but the electronics often die first. Beware the super cheap options as you get what you pay for.
Of course there is always the low-tech option of just replacing the Metal Halide fixtures with new ones. Less efficient, but tried and true.
 
Are these recessed (in the ceiling) or pendant or surface mounted fixtures? And do they have to remain the same?

Most of the LED high bay I use are 2' x 4' or 2' x 2' square and are amazing in their quality of light, and all silent.

In short, you'll be better off replacing fixtures if possible as the new fixture will inevitably be more efficient than the old fixture with retrofit lamp.

One of the neat things of LED house lights is that it make it easy to have a single system that does both performing arts house level and higher classroom level lighting in one system rather than two. Just suggesting you look and see if replacing one system if it wouldn't be the time to replace both with one, especially if your house lights are not already LED.
 
Are these recessed (in the ceiling) or pendant or surface mounted fixtures? And do they have to remain the same?

Most of the LED high bay I use are 2' x 4' or 2' x 2' square and are amazing in their quality of light, and all silent.

In short, you'll be better off replacing fixtures if possible as the new fixture will inevitably be more efficient than the old fixture with retrofit lamp.

One of the neat things of LED house lights is that it make it easy to have a single system that does both performing arts house level and higher classroom level lighting in one system rather than two. Just suggesting you look and see if replacing one system if it wouldn't be the time to replace both with one, especially if your house lights are not already LED.

our Current HID fixtures are recessed in the ceiling. And I frequently refer to them as "the Uglies" or Work Lights.

The theatrical "environmental/audience" houselights are 4 historical hanging chandelier like fixtures with 7 150w Hologen lamps in them. They are bright enough for audience light during events that require "mood." I've not made the switch LED because with out adding theatrical house light fixtures, the historical fixtures will not be removed. (they're pretty enough but have very thick yellow. glass and wrought iron framing.) They are a little bit of a pain to swap lamps out of but with my little custom audience platform and a 12 ft ladder it's something that I can do in a day with a student helper every 2 years (where i replace all of them at once.)

I need run over to the theater to clear some space anyways maybe i'll take a few photos :).
 
You have a no-easy-answer design challenge. I don't know if there are retrofit lamps that are both bright enough and quiet enough. Could be - takes research. After that do you want to replace fixtures; should they be recessed, surface, or pendant; and how do you deal with existing? I think there could be some 2' x 2' recessed LED lights - would look like a troffer but hopefully no worse than existing - which might take a similar physical space.

If this were my project I'd get as much info about existing and go to a lighting rep to help find a physical match to minimize replacement cost - cutting and patching of ceiling.

You probably would get some dimming for no cost, fwiw.
 
We are going to investigate with our physical plant deparmen, the Pendant Hanging style as noted in my first post hung from the ceiling joists in the attic over the existing openings for the recessed lighting. I'll keep you updated when we settle on or find the perfect solution.
 
We are going to investigate with our physical plant deparmen, the Pendant Hanging style as noted in my first post hung from the ceiling joists in the attic over the existing openings for the recessed lighting. I'll keep you updated when we settle on or find the perfect solution.
Good plan. That was one of the other details which crossed my mind - was there any need for the recessed fixture to be sealed - like is the attic a plenum space or is the ceiling the thermal barrier for the room.
 
With LEDs, it's worth noting that the ones with fans will probably last longer. The passive ones might have enough bulk and surface area for the LED chip itself, but aren't getting any airflow to the electronics. Capacitors are likely the most vulnerable component other than the LED COB.

A capacitor good for 65000 hours at 35°C can become 2000 hours at 85°C.
 

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