1400 Lumens at 1.4A?

[NewStuff]

I am looking at making my own stupidly powerful headlamp for use in Slate Mines (A very dense and dark material that just soaks up light). In my search for suitable emitters and drivers, I stumbled across this.

http://cgi.ebay.co.uk/20W-White-Squ...al_Components_Supplies_ET&hash=item3cb0990893

What, am I missing. It seems like a lot of light for the money.

Is is sane to think I can run one of these in a headlamp, partnered with an MC-E or similar (The silly bright one for Throw, the MC-E for spill to aid walking around in the pitch black)? Is it going to be very difficult to drive it (Short of PIC Programming, I can source components and build it)? It does strike me as rather inefficient, but I won't have too much space to play around with by the time I am done with heatsinking etc.

If I am wrong, or missing something, please, educate me.

All responses appreciated,

NewStuff

 

[jasonck08]

I don't think I'd recommend that LED. I'd stick to something from SSC, Cree or Luminus.

The specs are a little sketchy 1000-1500 lumens? Really there is that much variance?

So according to the specs, worst case scenario you'd have an LED that uses 25W's (18v x 1.4) and puts out 1000 lumens.

If you want something bright and efficient I'd say go with the SST-50 or 90.

Not sure how practical mounting one of these on a headlamp is going to be given the amount of heat they put out....

 

[spencer]

Expanding on the last post...

Worst case scenario 40lm/watt
Best case scenario (highly unlikely) 70lm/watt

XP-G is over 100lm/watt so I would stay away from this one.

 

[blasterman]

It's a common SEMI based array you see advertised on Chinese sites. You can get big power densities with them, but they aren't very efficient. 70lumen per watt tops. These chinese whites just aren't worth the trouble because if you want big power densities at low cost Bridgelux is both more efficient, cheaper, and has a more professional distribution network (in N America). The SEMI based arrays are really only worth the trouble if you need colors.

 

[AnAppleSnail]

About $30 US. The glowy part is 1cm across. You won't get throw like that, except for an aspheric head with a giant lens. That toss out a lot of your hard-won lumens. A reflector or optic would have to be HUGE to throw.

Go for a Triple or Quad XP-G and optic for throw, with something MCE-based snuggled nearby for flood. If battery voltage stays between 12.8v and 13.6v you can direct-drive the MC-E effectively (wired 4s), or you could give it its own driver. Note: If you try to use one driver for both, you'll need to disconnect it from its power supply BEFORE you wire it to the LED. You can control that with one double pole double throw switch. If you go with a microcontroller then you have things handled on your own.

How are you getting heat out of the heatsink? I've wanted to see helmet lights with aluminum bands around the hat for a while now.

 

[NewStuff]

I love this forum. Tose were exactly the kind of answer's I was hoping for. Educate me you have.

I don't think XP-G's will have quite the throw I am after though. If you are familiar with the Lupine Betty MTB light, then that is the kind of throw I need. Some of the caverns can be 200x500ft, and anything up to 300ft high, all made of a very dense, light absorbing material.

I would like efficiency, but the SST-50 seems very appealing. Looking around, I can get a WJ bin, which is touted as 500-600 Lumens at 1.75A, which seems reasonable to me indeed. Add to that the ability to drive up to 5A for Throw.

If I decided to use the SST-50, could someone recommend a suitable driver which can drive 5A max?

Again, If I have misunderstood something, please feel free to correct me. I am here to learn.

Thanks again,

NewStuff.

 

[tolkaze]

Bright is okay, but the problem with slate mines, coal mines, any dark hard rock style mine is that yes... they do soak up all the light. That is, until you run across some reflective tape, or a white sign, or another person underground who only has the standard gear... relfected light will hurt if its that bright

 

[NewStuff]

relfected light will hurt if its that bright

Very true. In my case however, it is fairly unlikely. These are abandoned mines I visit, there will be mabye 6 people, behind the camera. Full drive would only be used for short periods, 30 seconds at a time for photography purposes. I would be partnering it with a Q5 at 350mA or so for walking around.

 

[purduephotog]

http://www.candlepowerforums.com/vb/showthread.php?t=280671

I'd recommend something like this for what you want.

If you're lighting for a camera- do you mean still or video? If still, bring a strobe and /paint your exposures (with a tripod). You can't beat a multi-pop strobe for illumination.