How many amps should luxeon 3 watter pull?

elfen1

Newly Enlightened
Joined
Mar 8, 2005
Messages
96
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

Flashaholic
Joined
Feb 29, 2004
Messages
7,197
Location
decamped
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

Flashlight Enthusiast
Joined
Jul 22, 2003
Messages
3,635
Location
Louisiana
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

Flashaholic
Joined
Feb 29, 2004
Messages
7,197
Location
decamped
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

Newly Enlightened
Joined
Mar 8, 2005
Messages
96
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

Flashlight Enthusiast
Joined
Apr 18, 2002
Messages
2,639
Location
Boise, ID
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.
 

elfen1

Newly Enlightened
Joined
Mar 8, 2005
Messages
96
So one on the battery with tailcap off and the second where???
 

evan9162

Flashlight Enthusiast
Joined
Apr 18, 2002
Messages
2,639
Location
Boise, ID
Wherever the tailcap contacts the body - so basically, complete the circuit the way that the tailcap did.
 

Darell

Flashaholic
Joined
Nov 14, 2001
Messages
18,644
Location
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

Flashaholic
Joined
Jun 23, 2003
Messages
6,425
Location
central time
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

Newly Enlightened
Joined
Mar 8, 2005
Messages
96
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

Flashaholic
Joined
Feb 29, 2004
Messages
7,197
Location
decamped
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.
 
Top