Where to place HID Ballast?

[skizot722]

In reference to your reply to my post, and more specifically to my statement about not being a big difference between 4300 and 6000 in a halogen reflector housing:

I was speculating on that part. But where I was coming from, is that both 4300 and 6000 kelvin temps in a halogen reflector housing are both terrible RELATIVE to a projector HID. i was guessing that since the light is dispersed so quickly when used in a halogen reflector housing, that no matter what the temp, the output would be sh*tty. I based this only on speculation, whereas you know a hell of a lot more than me about it.

Does that make sense? Maybe I'm not wording it correctly.

Hey, pektel. I know what you're trying to say. I'll definitely agree that HID in halogen reflectors isn't the greatest compared to HID projectors. The thing to think about with halogen reflectors vs. HID projectors, is that the projectors are designed to focus the light so that it is 100% controlled, and almost all of the usable light can be projected below the cutoff line (the small percentage [~ 1-2%] of light that doesn't make it there is turned into heat as it hits the inside of the projector where it's not reflected). When you put HID burners into halogen reflectors, there's a certain amount of light that cannot be focused where it should be, so you end up with glare. And the simple definition of glare is "uncontrolled light".

So, to give a quick example, I'll use the lumen numbers from above - 5200 lm for 2 6000K burners and 6400 lm for 2 4300K burners. Now, say that the halogen reflector is able to focus 70% of the light when used with HID burners (the rest of it is uncontrolled light, which is what creates the glare). Because I don't know what the actual percentage is (and it absolutely depends on the design of the halogen reflector, which can vary, given the different halogen bulb types), the 70% is a hypothetical figure. So, the constant in the equation is the 70% of light focus, and the variable is the luminous flux of the burner (lm). With that, you'd have:

6000K light output: (5200 lm * 0.70) = 3640 lm
4300K light output: (6400 lm * 0.70) = 4480 lm

So, even though the projector (or actual HID reflector even) would do a lot better job, there would still be a difference in light output when using a 4300K vs. a 6000K bulb in a halogen reflector.

The one thing I will note from personal experience, is that it takes a little bit of adjustment when going to a projector setup. The reason for this is the dramatic contrast between the area above the cut-off line, and the area below it. It is purely dark above the cut-off line (aside from a little light that comes from the squirrel finder on some projectors), and totally lit below it. That's why it's hard to understand why some true HID fanatics are obsessed razor sharp cut-offs. I would think that with that sharp of a contrast line, it would be make it harder to adjust to the objects above it. But to each their own on that as well, I'm just glad the my projectors have a Fresnel lens. It gives a slightly blurrier cut-off, but that in return blends the light and the dark a tad bit better.

Sorry for the rant, I can get carried away sometimes.

 

[pektel]

no, it's all good info! I am not very well educated on the specifics, so my way of thinking sounds like it may be off.