Potential CREE host questions

[FlashCrazy]

I have a couple of lights with stars in them and would like to transplant Cree stars into them. One of them (has a Luxeon III) currently draws about 1100 mA from the battery, the other is 2 mode...high draws about 1900 mA (on a K2) from the battery, low draws somewhere around 800 mA. My question is, will a Cree draw a different current than I'm seeing now, or is the current just determined by the driver circuit? For example...the first light I mentioned draws about 1100 mA from the battery with a Lux III...if all I did was swap a Cree into it, would it still draw 1100 mA from the batt? Would the Cree see the same amperage as the Lux III does now?
How about the second light, drawing 1900 mA from the battery...I'd say about 1400-1500 mA is getting to the K2, correct? Would 1500 mA fry a Cree? I know Cree says they're good for 1A continuous. I know, lots of quesitons...but thanks for any input!

 

[wakibaki]

Chances are that the current is limited by a driver, but without more details it's not possiblle to be absolutely sure.

The Cree has 8ºc/watt thermal resistance, the K2 9º and the III twice that. (If I've read this wrong I'm sure someone will correct me).

An optimist might look at it like this: - they're all rated 3W and the Cree has the lowest thermal resistance and puts out more energy in light (less heat) than the others, so it should handle anything a III or K2 can.

$7.25, if it blows up you can put the old LED back, it's a star so no soldering the LED itself. If the LED goes the driver will probably survive. Probably...

Let us know.

w

 

[FlashCrazy]

$7.25, if it blows up you can put the old LED back, it's a star so no soldering the LED itself. If the LED goes the driver will probably survive. Probably...

Let us know.

w

Sometimes you just have to step back and look at the big picture. You're absolutely right! It's only $7.25....what am I worried about?! :laughing: I'll order some and try it out.

 

[Lighthouse one]

I did some bare battery testing..just playing around with a Lux lll and a cree P4 I just got....just the battery, and my meter on amps....3.7 volt nicad
the Lux lll drew 850 ma. the Cree P4 drew 510 ma. just one simple test..don't know if that proves anything or not?

 

[FlashCrazy]

Thanks Lighthouse! That's very good info.:goodjob:

 

[LED_Thrift]

I did some bare battery testing..just playing around with a Lux lll and a cree P4 I just got....just the battery, and my meter on amps....3.7 volt nicad
the Lux lll drew 850 ma. the Cree P4 drew 510 ma. just one simple test..don't know if that proves anything or not?

Which of these two LEDs looked brighter at these drive levels?