Retrofitting Metal Halide Works/Ghostlights with LED

StradivariusBone

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Our stage has 8 400w Metal Halide lamps that are used as ghost lights. A bit overkill to say the least. They are noisy and they don't function well as work lights because of that.

I was looking into retrofitting LED's into the fixtures themselves, but haven't found much info. Some sellers online seem to have kits that supply a ~120w LED fixture with an in-line ballast that I'm assuming bypasses the ballast inside the existing fixture. I'm not sure how these work without voiding the UL listing of the fixture. These are shoebox shaped enclosures BTW.

The other option would be to replace the fixtures with new LED enclosures. I'd like to find some with a lower color temp since the 4000k HID lamps don't help us when we're trying to match colors on stage.

Anyone been down this path before?
 
Why not just remove the old fixtures and put in some Osram LED work lights? I haven't used any but there is another thread floating around and people seem pretty happy with them.

If you modify your existing lights you'll loose your UL listing. If there is a mishap, insurance will not like that.

-Aaron
 
Why not just remove the old fixtures and put in some Osram LED work lights? I haven't used any but there is another thread floating around and people seem pretty happy with them.

If you modify your existing lights you'll loose your UL listing. If there is a mishap, insurance will not like that.

-Aaron

I was watching that thread too, did the 90w version come out yet?
 
I would hold off for awhile. Lower wattage LED lamps plummeted in price, but the high power floods are just starting to drop. I suspect a year from now you would be kicking yourself over what was paid for them! I converted the facility I am at to all LED lighting indoors (offices, etc) but we also have about 20 MH and HSP high power fixtures outside that I am holding off on. Prices were about $600 each two years ago, now they have more than halved and appear to still be headed down.
 
There have been service bulletins on retrofitting high-output mogul based CFL's in to high bay metal halides, but it was all provided by Maxlite (the lamp manufacturer), so I doubt it's a compliant change from a fixture standpoint.

It is an easy mod though, as long as you have a 120v supply to the MH's. I think they even make 277v lamps but again, these are CFL's, not LEDs. I think they also make the huge COB LEDs but I never really looked in to it much.

I used their 150w CFLs in their own fixtures (basically an MH reflector without ballast) and they were bright, but also ran about 4000k in color temp similar to MH.


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I just used LED troffers - similar to high bay flouresvents - and really nice. Look at Lithonia I-Beam but there are others with a range of color temps. Very good to at least to 30 or 35 seat. I think in the $300 range. Just replace - you'll do much better in long term.
 
Big Ass Fans just came out with an LED high bay as well.


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The biggest thing I was wondering is if there is such a thing as a drop-in replacement. I know some LED tube light retros are capable of this, but that's a lot lower wattage ballast. I've seen a few mogul LED lamps that claim to have this functionality, but I'm skeptical. I'm thinking it would still be necessary to bypass the ballast.

If we swap the actual fixture it could become a litany of paperwork as some building projects like this have to go through a special process that seems to be designed to take 15 years to do anything. On a separate issue- I was trying to find out if we could core some rat holes through our proscenium wall and yeah, it's a ridiculous amount of paperwork plus an engineering and architectural study which would cost 4-5 times as much as it would to do the actual work. This is next to 2 smaller holes that were drilled without permission (not by me). Note- I'm not knocking the need to do studies for certain projects. If I were coring a new door or hanging truss I'd be all for it, but this process applies to the smallest projects on up to building new structures.

However I have found that they are open to swapping lighting to LED especially when in our situation it might save as much as $1200 annually on electricity costs alone.

Here's an example of what I was looking at. Granted, any company that has "Green" in their name automatically turns on my BS-detector. This video seems to provide more info, albeit on a different product-

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In our situation, it would be far easier to keep the existing housing and just swap the guts out. I would still have to get our electrician team to do the work, but I think they'd buy in quicker since it's essentially the same process as swapping out a bad ballast which they do on a regular basis.
 
The biggest thing I was wondering is if there is such a thing as a drop-in replacement. I know some LED tube light retros are capable of this, but that's a lot lower wattage ballast. I've seen a few mogul LED lamps that claim to have this functionality, but I'm skeptical. I'm thinking it would still be necessary to bypass the ballast.
First, figure out if the lamps / ballasts are pulse start or probe start. 400 watt lamps are usually probe start, but you want to make sure they are not pulse start, which incorporated a high-voltage starter system that might pop the circuit in a "direct swap" LED replacement. Second, most probe-start ballasts are auto-transformer type, and output a voltage much higher than the line voltage. No matter what, the ballast itself is going to eat up wattage. I don't think there are many ways to do a direct swap without disconnecting the current ballast. New stuff comes on the market almost every day, so who knows!
 
Why not just remove the old fixtures and put in some Osram LED work lights?

You don't even have to buy Osram ones.

I bought some generic 80W chinese made ones from a big chinese importer here, they cost literally about $30 a piece and they are bright as you like. 2 years down the line not had a single one go wrong, and we are plagued with dust, rust, and high ambient temperature issues like most of the shore-side venues here. Cooling is heat sink and they are completely sealed units.

If you can pick some up in a hardware store or on eBay I would recommend it, not putting Osram down at all but LED chips in China now are fine really... I support buying proper brands for theatrical LED fixtures much more because of things like flicker free operation and colour matching, but for work lights these things are not so much of an issue really and if one unit slightly differs to the next in appearance, parts or colour temp then so what.

In any case I agree with you... in the shop I bought these, the complete unit was only maybe $10 more than the chip alone and comes complete with the body and all the wiring... definitely just buy it as a oner. They're also about a quarter of the physical size and weight of the old MH ones.
 
You don't even have to buy Osram ones.

I bought some generic 80W chinese made ones from a big chinese importer here, they cost literally about $30 a piece and they are bright as you like. 2 years down the line not had a single one go wrong, and we are plagued with dust, rust, and high ambient temperature issues like most of the shore-side venues here. Cooling is heat sink and they are completely sealed units.

If you can pick some up in a hardware store or on eBay I would recommend it, not putting Osram down at all but LED chips in China now are fine really... I support buying proper brands for theatrical LED fixtures much more because of things like flicker free operation and colour matching, but for work lights these things are not so much of an issue really and if one unit slightly differs to the next in appearance, parts or colour temp then so what.

In any case I agree with you... in the shop I bought these, the complete unit was only maybe $10 more than the chip alone and comes complete with the body and all the wiring... definitely just buy it as a oner. They're also about a quarter of the physical size and weight of the old MH ones.

Well,
If OP is concerned about voiding the UL listing on their current fixtures, I am sure they are not going to be interested in purchasing non-listed fixtures.
ESPECIALLY as ghost lights. The last thing I would want is an unlisted fixture being used for hours on end in an unattended venue.

Also, Color temperature and CRI are incredibly important for work lights, if you do any painting at all in the venue.
 
Big Ass Fans just came out with an LED high bay as well.

The commercial they have for those is awesome, with a Ford F150 driving on top of them, guys jumping on them, etc. Only downside is the color temp is only shown for 4k and 5k...
 
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You don't even have to buy Osram ones.

*Gasp* I have to FULLY disagree with this statement. Just my two cents being added in... ;-)
 
Well,
If OP is concerned about voiding the UL listing on their current fixtures, I am sure they are not going to be interested in purchasing non-listed fixtures.
ESPECIALLY as ghost lights. The last thing I would want is an unlisted fixture being used for hours on end in an unattended venue.
As a general rule, I'm opposed to the building burning to the ground in the middle of the night.

*Gasp* I have to FULLY disagree with this statement. Just my two cents being added in... ;-)
I like the worklights you all are offering, but does OSRAM have any models of these drop in replacements? I think we're leaning towards those (in the long run, as @JD suggested) as it will be probably be less paperwork than replacing the whole box. You all already get my business on tungsten anyways so no lost love! I've not had happy experiences with Ushio's.

First, figure out if the lamps / ballasts are pulse start or probe start.
They are probe start, just a big ol' transformer sitting in the box.
 
I absolutely challenge the spec. given on this product. http://www.gogreenledinternational.com/200w-high-power-led-side-light-with-external-ul-power.html
I don't know of any drop in LED retrofits that can deliver the output and performance of the lamp it is replacing currently, beyond 100-150W, which is why so few are being made. Especially without a fan. The fact that they list the product as being 200W of LEDs and reaching 50,000 hours with an ambient temperature range of -34°F to +131°F (50,000 hrs. at 131F? *LAUGH* Riiiiiiight. Do they also offer a bridge in Brooklin at no addtional cost?) Please note that ONLY the LED driver has a UL rating, not the LED engine portion or the entire system....
 
Come to think of it, ballasts in troffers are already being bypassed with the advent of LED tubes. I think many of them have the option to not be bypassed but a lot of people probably do, especially as the old ballasts die off (since fully replacing every troffer in an office building is a huge, expensive undertaking). I haven't heard any outcry from that, and what you're wanting to do isn't much different. Maybe you should contact a company that specializes in field retrofits and get their opinion. Usually it's the re-lamp companies that handle retail stores, parking lots, and industrial facilities (Staybright Electric is one such company).

I think the biggest hurdle would be finding a suitable replacement that will give you the lumens and color temp you expect with the lifespan needed to make financial sense. There are many products that claim to work but I have yet to see any in the wild. I remember seeing some round tubular fluorescent lamps in the high bay fixtures at a Northern Tool, but I don't think it was a retrofit (I believe they refer to them as "induction" fixtures). They did look just like MH.
 
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Riiiiiiight. Do they also offer a bridge in Brooklin at no addtional cost?)
Like I said, if there's the word "green" in your company name, it probably stands for grass-fed beef byproduct.
 

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