Overdriving the SST-50, how much is too much?

Codiak

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Dec 7, 2009
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Techjunkie has shown the SST-90 can draw more current than the 9A it's rated for and keep coming back for more, > 12A in the video.

I'm wonder if 5.6A safe for the SST-50?
How about 6A?
 

PMM

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Feb 17, 2009
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That is not a question that can be easily answered due to many aspects that need to be observed.

1) Heat - Is your enemy don't sink the LED well enough it matters not what you push through.

2) Capability of the wire's feeding the LED within the LED chip package itself.

So essentially design / construction has a large influence on what could be achived.
 

J_C

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Oct 14, 2007
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I don't have an answer but I have a question. How steep a lifespan decrease curve do you consider still "safe"? Even after your answer I still have no answer.:whistle:
 

Codiak

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50%

Twice as bright half the life is reasonable.... (not expecting increased lumens)
 

Techjunkie

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"Safe" is a relative term :devil:

As long as you can heatsink the emitter well, the SST-50 should be able to handle 6A. I'm running one at 5A here and as the emitter "burns in", and Vf drops, I expect the parallel drivers to push it closer to 6A.

I'll say this though - I left this torch on with the bezel/lens/reflector removed to burn-in the emitter and stress test the drivers and after ~10 minutes, I touch-tested it and the head and neck were to hot to be able to hold more than a few seconds bare-handed. In practical use, where my hand is constantly cooling the torch and the torch isn't stationary, I wouldn't expect it to get quite that hot. (After a while, I might be running a fever though.:p)

I have most of the parts gathered to build an SST-50 running at 5.4A, using dual 8xAMC7135 regulators and a 4.8v 4s2p 8AA Duraloop pack. I just need to find a heatsink slug like Elektrolumens used to make that fits snugly into the neck of a Mag D and can be recessed, like the brass pill fit into the neck of the Mag C after I honed the neck. Thermal management should be a bit better there in the D than in the C.

As for life, I don't think you'll get the 50/50 trade off. Running a high power white LED at max current will surely reduce it's life span (or service time to reduced lumen maintenance) much, much faster than running it at lower current where less heat is generated. I look at it this way, I'll want a brighter torch with next gen LED long before I've killed my current one by running it at max current.
 
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