How many amps should luxeon 3 watter pull?

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elfen1

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I have a drop in replacement bulb thats pulling 4.6 amps and measures 3.5 Volts on 3 D NiMh 9000Mah batteries? Its the replacement from qualityitemsonline.com. Whats the max a luxeon 3 watter can take? And any more info would be great!!!
 

idleprocess

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That depends on the heatsinking.

Under nominal conditions, Lumileds rates the Luxeon III at a maximum of 1000mA (1 amp). If you can keep the die cool enough, you can push more current through the emitter, but at the price of lower efficiency and more heat.

I hear that the gold bond wires inside the package are prone to failure when more than 3A flow through them.
 

Chop

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I'd have to take a guess and say that it's pulling way too much current. Direct driving an L Vf Lux III on 3D cells will only get you just over an amp, IIRC. Maybe it was 1.2A.
 

idleprocess

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Also - 4.6A x 3.5V == 16.1W. That's too much power for the LuxIII package even with an infinite heatsink.

The LuxIII emitter package has a resistance of 13 C/W ... 16.1W x 13 C/W == 209.3 C ... too warm for the die to be happy for long.
 

elfen1

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I was measuring it wrong I tested it the right way and got .5 amps using 10amp max on my multimeter and it showed 144 on the max current function of 400Ma. I put one probe on the positive lead to the LED and the other on the battery. So any suggestions which function is correct?
 

evan9162

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Use the 10A scale, and don't measure at the LED. Take off the tailcap of your light, and complete the circuit with the leads of your DMM.
 

evan9162

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Wherever the tailcap contacts the body - so basically, complete the circuit the way that the tailcap did.
 

Darell

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LOCO is more like it.
Something is wrong here, I'm guessing. At over 4A, that emitter wouldn't still be releasing photons! I've destroyed emitters with MUCH less current than that!
 

turbodog

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After you have measured amps, put the tail back on. Then set it for voltage and measure it at each side of the led.

Then get back to us.
 

elfen1

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OK I have it all figured out now sorry bout all the mix up I was shorting it and getting 4 amps it's really 620Ma at 3.36V and 80C is the temp after like 15mins. Now that thats all figured out what is a good max temp for a 3 watter and max amp draw for my upcoming project I want to use 4 3watters on a custom sink I have. So what is the best star for this since I've heard about different BIN's producing different forward voltage . I'm looking to use LXHL-LW3C is there abetter white 3 watter?
 

idleprocess

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LXHL-LW3C is the part number.

The bin - which specifies flux, tint, and forward voltage - would be expressed as SX1K or TWOH or somesuch.

Take a look at the "Luxeon binning" link in my signature for info on Luxeon bins and how to decode them.
 
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