low priced HPS ballasts

[barawn]

Hi all:

Someone posted on the DIYPJC site about a vendor on eBay who has a bunch of low priced magnetic 400W S51 HPS ballasts for sale for $28.99 plus shipping (should be ~$10-$12).

Good source for those who want to use the Ushio MH conversion light, I think.

[Guy Grotke]

I just ordered one of these from the eBay vendor. The cheapest price I found elsewhere was more than twice as much! They still have a bunch of these as of tonight.

Buyer beware, though: These are High Pressure Sodium ballast kits (including condensor, ignitor, and mounting hardware). They will only work with a retrofit MH lamp like a Ushio UHI-S400DD. (Which is a very nice lamp.) NOT with a normal or pulse start MH lamp. The other gotcha is the shipping cost. They weigh 16 pounds and ship from Fairview, TN. You can use the UPS shipping calculator to calculate your cost: $12.45 for me in California.

[gabel87]

This is awesome. Solves my $ problem. I ordered one of these and a ushio lamp. The lamp cost more than the ballast, lol. Thanks for the tip barawn

[qytum]

Thanks barawn, been looking for a cheap source.

Also thanks to Guy Grotke for your advice in my thread.

I take it you all are getting the bulb from the atlantalightbulbs.com site?

[Guy Grotke]

I order those from atlantalightbulbs.com: $38 US + shipping

They have a great price, and they ship fast with good packing.

You could check around locally to see if anybody nearby stocks them. I doubt they would be cheaper.

This combination has to be the cheapest 400 Watt MH light source now available, with a good color temperature (5200 K). Anything cheaper will be a lamp bigger than your head, and with a 4200 K or lower color temp.

[Miedosoracing]

I tried posting it here, but it was saying something like search forum something, so i gave up. Anyways, glad someone posted it. Thought it was an awesome deal, and let me tell you, shipping is fffaaassttt. I got it before the other stuff I ordered before it.

[dvb]

Can anyone commit on these fixtures?

http://www.prolighting.com/fixtures-...high-bays.html

400watts with a 17in reflector, ballast, and blub for for under $150

[Guy Grotke]

This is not a great deal for a DIY projector, it is all designed for big-box store or warehouse lighting.

1) They don't say anything about the lamp, so it is probably one of those $23 cheapies: Big as your head, 4200 degrees K or even lower color temp.

2) That reflector will not work in a projector.

You are much better off with the $38 Ushio retrofit lamp and the $29 ballast, both the topics of this thread. That's only $68 plus shipping. (Lamp sockets for the Ushio are available everywhere for about $8.) You get a fairly small lamp with excellant color temp. For a reflector, you can use a polished stainless steel mixing bowl. That'll add another $10.

[dvb]

Guy, You are correct, it would be bigger than my head. My though was that with a reflector that big, putting out almost parallel light you might not need a fresnell lens on that side. And you are right again about the color temp., it's listed as 4000k, 36000 lumins, and 20k hours life. (They did have free shipping.)
Oh well. I really appreciate the time you spend helping unknowlegable people like me. I know it's going to save me money and result in a better PJ.
Question. With a bowl, would you mount the lamp in front or you cut a hole and insert the bulb?

[Guy Grotke]

You could do without a condensor fresnel, if you had a parabolic reflector at least the size of your LCD. But the reflector in that fixture is probably not a parabola! If it was, and the lamp arc was placed at the focal point, then the light would leave the fixture in a tight beam to illuminate a very small circle on the floor. That is not what you want from a store fixture. You want the light to spread over a very large circle, so you don't need too many fixtures to light up your big box.

A mixing bowl reflector is just one example of a "found item" that may work as a spherical reflector. Other such items include very large soup ladles and quiche molds. (You can also pay for a real aluminized glass or dichroic spherical reflector from an optics supplier.) The key features for a useful found object are a highly polished stainless steel, aluminum, or silver surface (65%, 90%, & 95% reflectivity respectively), resistance to heat (ie. no plastic), and a perfect spherical section shape. it doesn't need to be an entire hemisphere. It just has to be a large enough section so that reflected rays light all the corners of your condensor fresnel.

You place the center of the lamp arc at the center of curvature (equidistant from all points on the sphere surface), so all reflections pass back through the arc. If you start with a full hemisphere, then you need to cut holes for the lamp to get to the center of curvature. If you have a smaller section, then cutting may not be necessary. Either way, you need a good stream of cool air around the lamp with a spherical reflector. Otherwise the lamp will get pretty hot since quite a bit of the reflected light gets absorbed in the lamp.