131,410 lux! (OddOne's BL-3000-fun thread)

131,410 lux! (OddOne\'s BL-3000-fun thread)

A little update to my earlier saga regarding a new LED acquisition...

The LED, in case anyone missed it - the BL-3000 from Lamina Ceramics...


Still, a super-LED needs a driver of some sort to make the most of whatever you're using as a power source, so I did some designing and SPICE-modelling of a switching power supply. A little work in ExpressPCB's board designer and $59 later, these arrived...



Oooh, my precioussssssss....


The parts to populate the boards had already arrived - it's designed to push 2.5 AMPS into the LED for as long as a 12-volt battery can deliver enough power, so all the parts are rather high-current. Basically your garden-variety boost regulator rigged to run as constant-current instead of constant-voltage.



That giant coil is a 60uH 16A choke, and it weighs about two pounds by itself. Hey, if you're gonna build something to drive high current into what electrically looks like a near-short, you use the big parts.

That plus I can't see for crap anyway, so trying to do it in surface-mount parts is an exercise in "I'll just buy one of George's BL-3000 driver boards when he starts selling 'em."


Testing time...



Driver plus BL-3000 on a piece of half-inch-thick aluminum plate, powered by a Power One SPL250-1012 monster PSU. Used to use another of the Power Ones to run a TEC in my computer's cooling system - they're about as tough as you're going to find (and expensive as hell - $380 each new!)


Apply power and step back...



MY EYES!!!!!!!!!!!!!!!!!!!!!!!!!!11111oneoneoneeleventygazilliontotheinfinitepower

Yep, it works. /ubbthreads/images/graemlins/grin.gif


Sneak peek of the next step...

Here's the reflector the LED is going into:



I know folks here have been trying desperately to figure out how to collimate the light out of an LED that size, so here's the answer:

Reflector out of an Altman stage/theatrical light, muahahahahaha...


I have a light meter coming in tomorrow's UPS (hopefully), so I'll be able to get hard numbers on the LED running at its ideal power level.

oO

Re: More fun with a BL-3000 LED...

Cool!

Larry

Re: More fun with a BL-3000 LED...

UPDATE!

Got a light meter, and took some readings. Assuming a feed of 2.5A into the BL-3000, I got ~320 lux at one meter from the LED, and ~3,500 lux at one foot. That's with NO focusing of any sort, the LED simply radiating openly into space. I'm now thinking that 10,000 lux (at 1 meter) is not at all unrealistic when I get the LED mounted within the reflector...

/ubbthreads/images/graemlins/faint.gif

oO

Re: More fun with a BL-3000 LED...

Okay... I set the reflector over the LED to catch SOME of its light, and got a reading of ~11,600 lux at one foot. And that was not even remotely close to properly focused. Hell, that was with the LED outside the reflector, shining into it through its bulb hole.

Suddenly I'm wondering if 20,000 lux at 1m is realistic!

/ubbthreads/images/graemlins/wow.gif

oO

Re: More fun with a BL-3000 LED...

Approaching hot wire territory. /ubbthreads/images/graemlins/smile.gif

Re: More fun with a BL-3000 LED...

Would a Thor reflector be just as good? What wattage is this agian?

Re: More fun with a BL-3000 LED...

Probably not, and input power measured at about 28W.

oO

Re: More fun with a BL-3000 LED...

An update!

Got the first part of the heatsink...



Yep, it's a solid copper bar. Not copper plated or anything. Weighs about four pounds.

My plan is to thread it, get a large chunk of aluminum bar, cut fins into it, and bore a hole into it that will also be threaded to match. Then, I'll coat the threads very lightly with Artic Silver and screw the copper bar into the aluminum to complete the heatsink assembly.

It should be able to shunt over 20,000 BTUs of heat away from the LED, so I'm not expecting thermal issues from the end result. /ubbthreads/images/graemlins/grin.gif

oO, firm believer in the philosophy of "go big or go home"...

Re: More fun with a BL-3000 LED...

Sweet!

Jeff

Re: More fun with a BL-3000 LED...

WOW.. gunning for the brightest LED light title

Re: More fun with a BL-3000 LED...

Well, someone has to say it...

/ubbthreads/images/graemlins/popcorn.gif /ubbthreads/images/graemlins/popcorn.gif /ubbthreads/images/graemlins/popcorn.gif

Definitely gonna need sunglasses when this is done...

Re: More fun with a BL-3000 LED...

will it be available on Ebay?

Re: More fun with a BL-3000 LED...

eBay? Who knows. /ubbthreads/images/graemlins/grin.gif

Anyway, I took that copper chunk and cleaned up its ends. (It was cut from a larger rod with a bandsaw, and not at all cleanly, so I had to square up the ends and smooth out the cut marks a little.)

Then, I lapped it. For those not familiar with it, lapping a heatsink is essentially the process of flattening and smoothing the mating surfaces so as to minimize surface imperfections (milling or extrusion marks, etc.) and maximize contact. This in turn creates a smoother thermal interface, needs less thermally-conductive heatsink compound, and makes for a lower thermal resistance from heatsource to heatsink. In processors you can easily pick up 3-5 degrees C by lapping the heatsink.

I started with 600 grit sandpaper, moved to 1500 grit, and finished up with some Brasso, and the end result isn't too bad for totally done by hand:


A close-up for detail:

Yep, that's the reflection from the copper rod end.

It's very close to optically flat except at the edges (you always have a slight meniscus effect when hand-lapping), and is flat enough that when I place the BL-3000 flush against it and lift up suddenly I can feel the faint vacuum formed from the closeness of the fit. Should make for a VERY good thermal junction. /ubbthreads/images/graemlins/grin.gif

I might lap the BL-3000 just a smidge too. /ubbthreads/images/graemlins/wink.gif

oO

Re: More fun with a BL-3000 LED...

I see said the blind man

Re: More fun with a BL-3000 LED...

Okay, not even taking into account how excellent a thermal contact that is going to create, that sure is a beautiful finish.

What's the back of the LED module like? It going to need any similar treatment?

Can't wait to see this thing running at full power with the reflector in place!

Re: More fun with a BL-3000 LED...

Dang I almost thought I was back at [H] for a while /ubbthreads/images/graemlins/wink.gif

Now get to work and put that thing in its home so we can get some beamshots already! /ubbthreads/images/graemlins/grin.gif

Re: More fun with a BL-3000 LED...

Dontcha mean [M], Rob? I'm just about the king of spam-free threads over there any more, hehehe... /ubbthreads/images/graemlins/grin.gif


My next trick will be to acquire a lathe to turn the threads into the copper and shape the aluminum I'll get shortly into the other half of the heatsink. Then, I'll lightly coat the copper threads with Artic Silver, spin it into the aluminum, and lock it in place with a setscrew to complete the heatsink unit. I'll also fab up some clips out of music wire to attach the LED to the copper, and then it'll be time to make the head enclosure and find a suitably large Pyrex window for a bezel. (Edmund Scientific carries several suitable candidates.)

And, the back of the BL is very smooth, but could stand a very light dressing.

oO

Re: More fun with a BL-3000 LED...

very nice !

I have been thinking of gettting one of these led arrays myself.
I have always wanted to make an electric version of a colman lantern /ubbthreads/images/graemlins/grin.gif

The copper rod shoudl work great, nice job in the polishing job, thats always hell by hand.

So, did I read correctly that you plan to thread the copper rod, and thread the finned AL sink, and screw them together?
I may be wrong, but I think press fitting the teo together would make a much much better thermal path.
Even good threading has gaps, and you dont want thermal grease/expoxy doing all the work for you.
I would think about press fitting them, with alittle thermal compound also.
freeze the copper, and heat the AL sink, works wonders.

Cant wait to see more on this project !!!!

~John

Re: More fun with a BL-3000 LED...

I'm posting pics because if not for pics I'd not believe this...

Set up a test with the BL-3000 on the copper rod inside the reflector:


Applied power:


(Yes, this is WITH camera flash.)

Set my Extech 402010 lux meter to 10x (0.1mv = 10 lux), plugged it into my Fluke 89-IV DMM, held the sensor at 1' from the LED, and took this reading:


Since it's set to 0.1mv = 10 lux and the DMM direct-reads down to 0.1mv drop the decimal point and add a zero for the reading.

Yep, that means...

You guessed it...

131,410 lux.

/ubbthreads/images/graemlins/faint.gif

The LED is NOT positioned in the reflector's focal point, either - I need to fab up the mounts and widen the reflector's bulb hole to make that happen. Once it does I should remain pretty close to that reading at 1 meter.

oO

Re: More fun with a BL-3000 LED...

/ubbthreads/images/graemlins/eek.gif