12000 lump lamp???

[jawnn]

I realy don't know where to put this question, so here it is::naughty:


I want to replace an ac 75-watt quartz halogen spot bulb that claims 11000 lumens…is there a reflector that will produce a one-foot wide beam at two-foot distance? And what kind of led to put inside??

Or is there an existing bulb that will do the job??? Maybe I'm just too far ahead of the tech???

 

[R33E8]

Heh.. 1100 or 11000?? if it's 11000 you might want to keep it because it would be hard to find an LED that efficient (147lm/w) to be that bright..

For 1100 lm you could probably used 2 or 3 Cree MC-E's or P7's.. I have no idea what to do about the reflector part...

 

[StarHalo]

I see an array of 40-50 single-die power LEDs, each with its own optic (see also: Data Bank 70), all set into an Archimedes-type reflector with moving/tilting surfaces around the outside so you can adjust the concavity/beam focus distance. Good luck with that

 

[lolzertank]

Wha? 1100, 11000 or 12000? Anyways, let's first figure out the beam angle. 1 foot spot at 2 feet = 1/2 radians = ~30 degrees.

1100: 2 Cree MC-E/SSC P7 and 2x Ledil Boom medium reflector.

11000/12000: ~100 underdriven Cree XP-G (to keep it within 75 watts) behind the same number of Carclo frosted narrow 10mm optics. This won't be cheap.

 

[blasterman]

We can assume he's referring to a 75 Watt Halogen Par30/38 flood. These are about 1000 lumens.

Not that familiar with MC-Es, but inexpensive Acrylic / Carlco optics should be no problem.

How do you guys conclude he needs 2 rather than 3 MC-Es?

He'll also need to resolve heatsink issues and get a pretty heft driver.

 

[znomit]

How do you guys conclude he needs 2 rather than 3 MC-Es?

550lm is probably a reasonable out the front value for a high bin MC-E at full noise. 20% optics losses from 700 led lumens.

 

[bshanahan14rulz]

I've seen a GU10 bulb at walmart, has a single acriche... not gonna be no 1200 lumens though...

 

[blasterman]

550lm is probably a reasonable out the front value for a high bin MC-E at full noise

Does Cree have documentation showing this?

Can you get this out-put at neutral white? If he's switching from Halogen (no idea what he's doing yet) he might not care for cool-white.

 

[lolzertank]

Cree has documentation showing the effects of temperature on output. The efficiency of the optics are in the optic's datasheet since the optics aren't designed by Cree.

 

[blasterman]

Cree has documentation showing the effects of temperature on output.

True...but their standard specs give lumen values quite a bit below what a few of you have stated.

Generally when I look at LED specs for projects I assume typical heatsinking and standard bin LED that's readily obtainable.

This considered, can I assume 550 lumens from a neutral-white MC-E on a standard heatsink driven at factory spec current?

 

[znomit]

True...but their standard specs give lumen values quite a bit below what a few of you have stated.

How do you figure?

Neutral is a bit down on cool but getting awfully close to 550.

Neutral white K bin is 370lm @ 350mA.
700mA is a tad over 1.7x that output.
15% optics losses.

Drop a bit for heat, add a bit for not being at the bottom of the bin.

http://www.cree.com/products/pdf/XLampMC-E.pdf