Learn me metal halide lights

I just picked up a 400 watt low bay metal halide light off of craigslist from a guy who should be on this forum if he isn't already (the man had a huge garage and 4 mg's for berks sake). I needed it because it turns out my new place has inadequate lighting and all of my house plants are dying, so I'm hoping this will help, but it got me thinking about garage lighting. My garage is dark, it's kinda bigger for a 1 car, an it has a fairly tall ceiling.

How many 400 watt lights would comfortably light the place? 2?

How many for extremely bright?

Do these things trip breakers if wired on the same circuit? I did the math and 2 wouldn't draw too many amps I think, but I'm not an electrical engineer, and my garage currently only has 3 compact florescent lights and a door opener, nothing else.

Any downsides compared with t5 florescent set ups?

Just curious because the price was good and he has a lot more. Also 175 watt ones, but I like the 400s because moar power.

It'll depend on the reflector and whether or not it has a lens.

How many on a circuit will depend on the circuit. If a typical 15A circuit on 110V house current, two would be OK, three would be pushing it. Three would be at the limit on a 115V, 15A breaker. The ballasts on older HID fixtures isn't very efficient so the actual input wattage can be 10% (or more) higher than the bulb rating. When doing circuit designs, I usually use 460W when calculating the loads with lights like these.

Downsides:

First, even a low-bay 400W fixture needs to be pretty high by residential garage standards. 14' minimum. Too low and you can get severe hot-spots and harsh cut-offs (again, depends on the reflector/lens, if any). For comparison, hi-bay 400W fixtures are often mounted at 30' in warehouses.

Second, the ballasts tend to be noisy (buzz).

Third, metal halides don't do hot-restarts well, e.g. you think you're done for the night, shut the lights off, forget something, turn the lights back on - it can be ten minutes before the bulbs will put out substantial light. For this reason, when I'm designing HID layouts in warehouses, every 4th or 5th fixture has a device called a "quartz-restrike bulb" which is a add-on device which puts out a minimal amount of light until the MH's get back up to operating condition.

I know when we switched our plant over from metal halide and sodium lights to modern flourescents the electric bill went down over $800 a month. Granted this was a 50,000sq/ft plant that ran 24/7 but it was a huge savings to go with different lighting.

Also the halide lights prematurely aged everything. Anything that wasn't UV protected became yellowed and brittle within a month of constant exposure. Even a sheet of A4 paper would look 50 years old after a few weeks.

I was involved in the selloff of the old fixtures and every person who responded to the CL ad was a long haired male in their early 20's who grew "vegetables" hydroponically. Must have dealt with 40 of these stoner kids. They all sounded just like Spiccoli from Fast times.

Um. Yeah. House plants. Riiiiight.

Metal halides are also subject to, as my EE professor put it, "spontaneous dynamic end-of-life". I'd go with a bunch of cheap 48" 2-lamp or 3-lamp T5s if I were you.

Yeah most plants that have switched away from these can't but give them away for scrap. If they run any substantial hours, the modern T5's will pay for themselves in lower electric consumption, and put more light in more places where you want it.

I've been involved in 3 facility retrofits that did away with metal halides and went to T5's. Also, metal halides will reduce light output substantially over their lifetime.

For a rarely used shop I guess the metal halides work if the slow strike/start isn't an issue, but otherwise the HO T5 setups are going to give you better lighting and big energy savings over time.

http://www.hoveyelectric.com/hovey-electric-power-blog/bid/55851/Energy-Efficient-Lighting-400-Watt-Metal-Halide-vs-T-5-High-Bay

Count us in as going from metal halide to fluorescent in our shop. Huge difference in electricity bills and we can't give the damn things away now. Plus the slow start time of the metal halides - even from cold - was a pain in the butt.

Check the price on a single replacement metal halide bulb. We have a few left here that I just bought replacement bulbs for.....to the tune of $112 for EACH BULB!

I'll stick with fluorescents.

True... the last HID warehouse I did was only because the client had a zillion of them already and up-front purchase cost was an issue. Everything we've done from scratch or renovations over the past 5+ years has been hi-bay T5.

For awhile, the HID manufacturers were pushing 'smart ballasts' that will dim the bulbs down to around 10% and activated by occupancy sensors (since most of the time, warehouse aisles are unoccupied). That way they get around the restrike problem while getting some decent energy savings.

When I first started working in this industry with supermarkets, HID fixtures were common, but now hi-bay fluorscents are the norm.

Btw, another thing that just occured to me - a 400W M-H ballast running on 110-120V is pretty rare. The more I think about it, if you're paying anything for these fixtures, you're paying too much.

I just upgraded the lighting in my garage with a combo of LED and T8s.

It appears the biggest mistake I made though, was not checking what the rebates were through my local electric utility and the requirements for meeting them.

If I'd researched this first, and followed directions, I might have been rebated as much as $200!

Thanks for the speedy replies!

Yeah this one is running 120v. The ballast has wiring marked for 110, 220, and something else (cant read, numbers smeared off).

Check the price on a single replacement metal halide bulb. We have a few left here that I just bought replacement bulbs for.....to the tune of $112 for EACH BULB!

I just checked amazon, they're $10-20 now, $25-35 at my home depot. $112 a bulb is crazy, I only paid $35 for this whole thing.

Um. Yeah. House plants. Riiiiight.

Ok, you caught me. They aren't really house plants, they are bamboo. Not lucky bamboo, actual bamboo, most species of which make notoriously difficult houseplants.

Random fact, I am a male in my mid 20's with long hair. When I picked up the light, the guy actually said "yeah, most guys your age are growing something" and literally made a mix of these faces: , further reason I suspect he's already a member here. I should email him and make sure he knows about this place...

Another random fact- I don't do any drugs. Not even alcohol. well, except caffeine. I do TONS of caffeine, though last night I may have had too much. I know, there is no such thing, but I had my usual 4-6 post lunch mt. dews, then went to child birth class with my wife where they served free coffee, among other things. Since half the people there are pregnant, they avoid the coffee, and the other half probably avoid it because it's 6pm and they wanted to sleep that night. The coffee was insanely strong (literally tasted like espresso), which I immediately noticed after the first half of the large cup. 20 minutes and 3 cups later (we sat next to the coffee table, obviously) i started vibrating slightly, which is normal. Then, the room started vibrating in my mind, which was probably a mix of caffeine and the disturbing images of the tools used, like forceps or their vacuum suction cup thingy . So I finished off the class with another cup of coffee and went home. I didn't exactly feel 'well'.

Back on topic, this light is buzzing pretty good, too, but I have hearing problems so that isn't really an issue.

What I'm getting from you guys is that I should just stick with the 1 metal halide light I have, and put something else (T5's or LED's) in my garage. Cool, I think I'll do that. I might still hang this one in my garage in the summer.

A guy I know uses a 400w metal halide to start seeds for his unusually gigantic back yard garden. He gets the plants used to this light at a very close distance, and when he moves them to his garden, the direct sunlight doesn't bother them at all. he had some kind of vines that grew freaking 30 feet in one summer with HUGE fruit hanging off. I don't know how much was starting with a large light in the winter, and how much was his insane gardening skills, but I wanted one of these things since then.

Rufledt wrote: Thanks for the speedy replies! Yeah this one is running 120v. The ballast has wiring marked for 110, 220, and something else (cant read, numbers smeared off).

Probably 277V, which is commonly how these fixtures are wired in commercial applications (when you look at lights in a supermarket, they are usually connected to a 277V source).

ok a few more questions.

Did anyone spending a large amount of time under this light have funny feeling eyes? I read these can put off UV rays, but I don't know if it's the light messing with my eyes, all of the lack of sleep I've had the last few weeks, or what. It might also be that I almost never actually get much light exposure and my eyes have adapted to CFL's and cave like darkness only. Who knows. I'm usually in the room with the light, but it is behind me, 15' away, and oriented such that if I look straight at it, I can't actually see the bulb, just the side of the reflector. I've also started wearing sunglasses when inspecting the plants for stress.

On that note I'm surprised, most of these plants (except maybe 2?) are shade loving forms of bamboo, and they aren't showing stress at all. No growth either, but it has only been a couple days and bamboo is weird in the way it grows.

This bulb also looks a bit burned on the inside, is it advisable to replace it at this point? I saw home depot carries an identical looking bulb rated at 39,000 lumens (3k more than this one) for $30, probably half of that on amazon. I don't know how old this bulb is, but it does work.

I experienced how poor this thing is as hot restarting. Good thing I don't need rapid on. It sat humming for like 4 minutes before humming slightly louder and finally starting to light up.

When i looked up the spectrum it showed more blue than red light, which I read is better for vegetative growth, not flowering. That's fine because Bamboo rarely flowers (it's often fatal), but I'm struggling to find too many sources about growing with these lights that don't link me to some kind of pot growers forum. I suppose if anyone has motivation for maximum growth it's pot growers, but since i don't use a proxy and I'd rather not have my house raided by the police, i'm avoiding those sites.

I have not read all the responses, But I can tell you that all of our MH lights on campus(my job) have severe yellowing issues, Also hot restart is a problem until they cool off. I would slap some 4 light t5's or t8's in there. you can fit more T5's on a single ballast for the sake of simplicity and cost. I'm on the fence on LED's right now.

I saw some bright LED spot lights designed for landscaping (lighting up trees and such) on amazon for pretty cheap, I think $45 or so for a 50 watt light at something like 8,000 lumens. That's not a bad deal, especially considering how little power they use, no warm up period, long life, etc...

I wonder about using that kind of thing for garage lighting, if they are designed with a wide enough beam, plenty of light, get a few of them for more spread out light. I may use this MH light in the garage anyway during the summer since it has a fairly high ceiling for a 1 car (there's no attic above it, just the underside of the roof) and my plants will be moved to the back yard.

Yeah I tried a hot restart when I moved the light once, it took 5 minutes before it started producing the light it would've the second I threw the switch when it was cold, and THEN took 5 more minutes to put out lots of light. I did notice one of my plants already starting to put of a lot more growth, not bad for a week, but it might just be bamboo's way of growing. They usually store energy, and then when growing season begins (started by lots of light) they explode. Some of them shoot at near visible rates, like many inches per day. Kinda crazy.

I did end up perusing some of the 'maryjane' type websites and noticed they use a mini grow room (small closet sized box with reflective material inside) and I think I can make a grassroots one out of cardboard and tin foil. Maybe I'll make an indoor gardening build thread out of it. We did get more vegetable seeds than we can fit in the sunny part of our yard, maybe this MH light will become a permanent grow light! I wonder if I could grow lettuce and peppers entirely indoors...