What to use to COOL down the Luxeon 3W

Hi there

I`m making myself a 3x Luxeon 3w bike light
I was inspired by another thread where a dude did make a very nice light to have on the bike\helmet!

But I soldered my 3 Luxeon LED and fire them up with a 11.1volt LiPo battery!
The light is perfect
But the HEAT from the 3 LED is "damn" HOT !!

I think a heat-sink is in place..
But do I need a big one, small one, no one ?


Thanx for help..
I can try to take some photos of the setup when I know how to set them up!



Filip
Norway

Computer CPU heatsinks are a good source of cheap heatsinks.
When you are cycling you will have a good cooling breeze to help it cool down.

If it is a bike mount rather than a headlight mount then if you can get a metal clamp to the frame then the whole bike becomes a heatsink.

Nick

OK

Thanx for the help...

I got another question ....

I run 3x 3W luxeon LED in serial with a 11.6 volt 1800mAh LiPoly battery !
Do I need any drivers to each LED (the light now is PERFECT)

And another question, how much current is this 3x LED take ?
I started to wonder becouse of the heat they produce...

If the 3 LED take to much power from the LiPoly, the battery will explode !!
And I really dont want that to happend

Any other in here got experience using LiPoly battery to run Luxeon ??


Cheers

What vF bin do you got on the luxeons?

What current is going trough them, can you measure?

Propably the current is a bit high with a 11.6v battery.

hmm..
I only know that this is a "regular" 3Watt Luxeon .. LXHL-LW3C
And they was supposed to have 3.7volt ? that give me 11.1 volt when 3 is in serial..

And I think the Lipoly is 11.6volt So that is perfect ?
My only worry is about the Amp that this led take, will they be to much for a LiPoly battery.......


(I did buy this led`s from elfa.se )

liteglow said:

I got another question ....

I run 3x 3W luxeon LED in serial with a 11.6 volt 1800mAh LiPoly battery !
Do I need any drivers to each LED (the light now is PERFECT)

And another question, how much current is this 3x LED take ?
I started to wonder becouse of the heat they produce...

If the 3 LED take to much power from the LiPoly, the battery will explode !!
And I really dont want that to happend

Any other in here got experience using LiPoly battery to run Luxeon ??
Cheers

Click to expand...

In series, the LEDs take the same current as one LED and the voltage of the 3 LEDs is summed (depending on bin about 3.75v ea) the 3 x Lux IIIs should draw 1A. and about 11.25V. An 11.6v LiPoly battery will be over 13v when fully charged so you are overdriving your LEDs with a fresh battery charge. Hopefully, you are using a LiPoly w/protection circuitry... dangerous otherwise.

I would use a single constant current driver such as an nFlex, bFlex, or a 3021 (or 3023) buckpuck to drive all three LEDs. You are probably overdriving the LEDs significantly by connecting them directly to the battery (thus the excess heat)... although they will get hot normally without proper thermal management. Without some form of current regulation you risk damaging the LEDs (premature loss of brightness).

I have a similar setup that I use a 4A, 14.8v Li-Ion battery with. See the TriLuxIII in my signature below.