Microfire HID vs. CREE XR-E

[myk]

myk: but did you take into account the focal length of the optic? That can add a lot of length to the setup..

the focal length of the optic is 13mm- which is from part way through the dome of the lense to the light source - and according to the specs the back focal length (from the bottom of the lense to the led) is 6.9 mm - which is actually much less than the 27.24mm height of the mcr27L

so i'm not sure how that would work exactly =) but it wouldn't be adding more than the inch bulge out the front of the head

 

[McGizmo]

For a down and dirty comparison, below is a beam shot of an Aleph 3 (luxIII of unknown bin) with a beam shot of a XR-E driven behind a 1" half ball (acrylic) lens that is not placed in sharp focus but adjusted for max lux reading (4600).

The "lens" is the bottom image and you can see there is spill by virtue of light bouncing off the Al housing behind the lens and out. This set up is certainly inefficient in terms of getting out all of the light but for a small OD head, the lux is respectable.

 

[slarty bartfast]

Looking on ebay, it seems a 47mm lens has a focal length of 50mm, which is quite far away. A 30mm one is only like 15mm focal length, which would be much easier to work with in a torch, but the beam would not be as tight... hmmmm

I was thinking about that as well and wanted to play around with the 30mm one on an XR-E and the 47mm one on a 20W edipower star.

 

[NewBie]

Here is another comparision of an aspherical lens vs. the HD45.

I defocused the lens to provide a lit up area. Sorry about the missing bite in the beamshot, thats my finger, I'm trying to take photos, hold the lens in alignment and also hold the LED. I defocused one way, and then the other way:

An outdoor shot of the CREE and throw possibilites, lighting up a beige house:

 

[nutz_about_lights]

Holy cow.... That's 245m! And the spot is still visible.... :goodjob:

 

[zelda]

I made also good experience with lens:

http://candlepowerforums.com/vb/showthread.php?t=90547

(The Lux III i used was an SX0H .) The color throuh a lens change to sligtly warmer. The angle beam is less then I wrote, it goes down to ~1-2°.

You can just find this type of lens in old Diaprojectors.

Zelda

 

[vic303]

Just wow! Hey Newbie can you post a pic of the CREE light itself? My DH has been asking how physically large the light is, that is putting out such and awesome beam!

 

[Archangel]

(grin) I like the stop sign. Except for the color, you'd think it was one of those small street lamps.

 

[srvctec]

(grin) I like the stop sign. Except for the color, you'd think it was one of those small street lamps.

At first, I thought the stop sign reflecting back was the actual spot on the house!! Glad you mentioned it. It's still a really impressive beam shot for that distance for an LED.

WOW. Just WOW!!

 

[Toons]

:thumbsup: NewBie!
You da' man!!! :bow:

Must go take cold shower now.
Thanks.... I think
Toons

 

[NewBie]

At first, I thought the stop sign reflecting back was the actual spot on the house!! Glad you mentioned it. It's still a really impressive beam shot for that distance for an LED.

WOW. Just WOW!!

Yeah, that beige house isn't very reflective, unfortunately. I wonder if they'd consider letting me paint a target on the side of their house at the very least...

 

[CM]

Since you asked, I figured I should go do it.

I had a tough time holding battery, lens, and camera all in proper alignment, so pardon the poor pictures. The portable power source I had on hand only delivered 700mA. I tried to optimize the focus on the Microfire also.

Distance is about 80 ft.

I just had to bump this picture again. Unbelievable!

 

[AndyTiedye]

So WHY am I hauling that big, heavy HID lighting system around on my ultra-light
carbon fiber bicycle again?

 

[NewBie]

So WHY am I hauling that big, heavy HID lighting system around on my ultra-light carbon fiber bicycle again?

Muscle building exercise.

 

[Luna]

So WHY am I hauling that big, heavy HID lighting system around on my ultra-light
carbon fiber bicycle again?

I'm guessing because you really want to see the road. Notice the lack of spill.

You can simulate the same result by putting a magnifying glass about a foot in front of a light and see what is happening.

 

[Archangel]

What he said. A reflector versus a huge optic is hardly a fair test for throw.

 

[NewBie]

Actually, the Microfire reflector is much larger than the aspherical lens.


I found an old spectral graph of the Microfire HID Warrior light:

 

[Justintoxicated]

Jar,
So in your opinion is the new Cree nearly as efficient or more efficient than a HID in terms of output?

 

[NewBie]

Once you include ballast losses, even the Philips Luxeons beat the lower wattage HIDs for efficiency.

So, obviously yes.

But you don't have the spot intensity of HID yet, if you just want throw only.

We still need to hold the LED's 80lm/W, and crank up the power further, or raise the efficiency more, which folks already have in the works, quite a number of ways to do this already.

If you don't need a pencil beam that throws for miles, then these LEDs will easily exceed the lower wattage HID. The bulb itself is roughly 45-50lm/W, and their ballasts are 70% efficient.
http://www.lamptech.co.uk/Spec Sheets/WelchAllyn MR11 10W.htm
http://www.walamp.com/lpd/files/datasheets/ISL305B2.pdf

Once you drop in the ballast efficiency, you are looking at 31.5 - 35lm/W.
Run it for 350 hours, and kiss another 15% goodbye, and you are left holding 26.7 - 28.9 lm/W


Jump up to the 21W unit, and you get 68 lm/W for the bulb. Subtract the 75% efficient ballast(25% losses), and you are left with 51 lm/W. In just 20 hours or so you loose 12%, and that leaves you with 44.88 lm/W.
http://www.walamp.com/lpd/files/datasheets/ISL290b.PDF
http://www.walamp.com/lpd/files/datasheets/LSL013e.PDF

Once you start moving up to 35, 50, things look better, and above 100W you start finding really efficient ballasts.

Every light source has it's advantages and disadvantages.

As far as whether the CREE is more efficient, it depends on exactly what you are comparing it to.

 

[AilSnail]

the welch 10w hid has a really nice color imo. nice to see the spectral graph newbie.