Can the LS stand the heat?

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milkyspit

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If memory serves, the stock Arc-LS drives the emitter around 333mA. I know lots of modders around here have boosted the current flow, but when I finally saw the inside of an LS it seemed to be just a circuit board without much heatsinking. Am I missing something? How does the light get the heat from emitter to housing?

Second part of the question, for all you modders: what's the hardest the LS can be driven without potential for heat damage becoming a real issue?

--Scott
 

BentHeadTX

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Scott,
I have been driving an R2H LS at 3.7 volts and 900mA with no problems. The star is thermal epoxied to an aluminum heat sink that is epoxied to a 2D Mag. It runs 12F (8C) above ambient temps so the heat is leaving very well.
Mr. Bulk runs up to 1.5 amps through his direct driven LS lights so things look pretty good.
I don't have much interest in Luxeons once they go past 800mA, they don't put out much more light considering the increased power. 700mA seems to be the sweet spot.
 

Rothrandir

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the ls's are small, but they can take the heat.

333 is a pretty conservative drive level.
even with more current the arc should be able to take it.

obviously it wasn't designed for serious overdrive.
it was designed to drive it soft, and it does so very well.
 

milkyspit

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BentHeadTX, I'm a bit confused. You're talking about the "Luxeon Star" (LS) itself, right? I was referring to the Arc-LS when I said "LS". DOH! My bad! /ubbthreads/images/graemlins/icon15.gif

What I wondered was how much current the Arc-LS can pump through the emitter without getting overheated and damaging something. I think Rothrandir is answering along those lines.

That said, I still found your post informative! /ubbthreads/images/graemlins/thumbsup.gif
 

Dan C

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I've got a three Arc heads that I'm running at 667mA. Two LS2 style and an older LS1. While they will get hot, it's not excessive as long as you hang onto them. It's viable I think, but I don't think I'd go any higher. I think the old Arc head is better at soaking up the heat as it's got more mass and more contact area with the converter board.

I wonder exactly what components would fail due to excessive heat? I've never had one 'shutdown' yet.......

Dan C
 

nexro

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I think the newer Arc LS have a thermal protection circuit to shut down the LS if it gets too hot. So, I think it is quite safe there.
So far, I haven't had any heat problems with my LSHF.
 

Floating Spots

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Actually, I think its the 123 cell that puts out most of the heat.
I have a mildly overdriven Arc LSH at a little over 400 ma.
It gets quite warm on long runs.
However, if I use other battery options, it doesn't get nearly as hot.
Actually, it only gets luke warm...
 

Rothrandir

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more likely is that the additional mass and surface area of the 2aa pack offers additional heatsinking...
 

BentHeadTX

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Milky,
/ubbthreads/images/graemlins/ohgeez.gif /ubbthreads/images/graemlins/banghead.gif Ooops, I guess I was a bit tired and assumed too much! I like Roth's idea, the 2aa pack offering more heatsinking. LS4 boosted running a 2aa pack sounds like the light for me /ubbthreads/images/graemlins/thumbsup.gif
 

hby

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No problems as long as you use with stock current.

I put LuxIII on Rev2.1 board with 0.075 ohm(about 750mA).
Thermal shutdown worked very well in 15 sec.
I may need some thermal resisting material between curcuit board and heatsink.
 

Red_Dot

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Dan C
interested in your mod of boosting the current to 667mA. If it's not too much trouble, can you send me a pm as to how this can be done ? I have a very white beam LSH which I think is a shame if it's left in its current state when it can do better. Thanks
 
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