Need directions

BeachBoy

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Jul 13, 2009
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I am trying to build a small (around 1" diameter) light running off a car power system. I'd like to be able to mount ~8 of these together, running from the same power supply.

My goal is to get over 900 lumens (ideally over 1000) from each light and be able to control the beam (using something similar to this?? http://ledsupply.com/opk2.php) I can put a large heatsink in the back, and they would be mounted in the front so get a ton of fresh air when the car is moving.. but they could spend some time on when the vehicle is stopped hence the need for a good heatsink.

I have read here that I need constant current because the car system is "dirty". Can someone point me where I can get a constant current regulator? I know the puckbuck but it's 1A and if I run 8 I guess I can connect them in a way that I could use a bigger power supply and connect them to send 1A or whatever to each one.

Now, what type of LED can I drive to get the most light out? Because I'm not running off a flashlight battery it can take a lot of power if needed.

sorry for these beginner's questions. I tried to find a beginner's FAQ and could not find it.

Thanks!
 

lolzertank

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You can put the LEDs in series and only use one buckpuck per 2-3 LEDs. If you only need 1000 lumens, 5 or 6 high bin Cree XR-Es (Q4, Q5, R2) at 1A is enough. Of course, you could use 9 to 10 at 350ma to decrease the amount of heat.
 

BeachBoy

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I only want 1000 from each light, then multiply this by 8 or so (in multiple clusters if needed).

---

I've done quite a lot of reading today, here's where I am now. I'm still confused in some of the technical stuff (especially Vf)

maybe use 4x MC-E driven with one hipFlex @ 2800mA with ludil optics (not sure which yet).

Few questions:

1- Is there something similar to the MC-E but more lumens? I like the fact that there are tons of Optics available for the MC-E

2- My car power supply is fluctuating, so the hipflex can only give out "Vin-0.5V". That means that on full power (14.4V let's say), the hipflex could deliver around 14v out. How do I calculate the voltage needed for the 3 or 4 LEDs? And on startup, when the voltage drops, would that break the hipflex/LEDs or they would just be dimmer while the car cranks (the hipflex would send 11.5volts or so for a few seconds)

3- Could I drive the MC-E at 933mA per die (using 3 MC-E instead of 4 with the hipflex)?

Thanks for your help and soon the basics questions will be out of the way ;)
 

lolzertank

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Dec 29, 2008
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I only want 1000 from each light, then multiply this by 8 or so (in multiple clusters if needed).

---

I've done quite a lot of reading today, here's where I am now. I'm still confused in some of the technical stuff (especially Vf)

maybe use 4x MC-E driven with one hipFlex @ 2800mA with ludil optics (not sure which yet).

Few questions:

1- Is there something similar to the MC-E but more lumens? I like the fact that there are tons of Optics available for the MC-E

2- My car power supply is fluctuating, so the hipflex can only give out "Vin-0.5V". That means that on full power (14.4V let's say), the hipflex could deliver around 14v out. How do I calculate the voltage needed for the 3 or 4 LEDs? And on startup, when the voltage drops, would that break the hipflex/LEDs or they would just be dimmer while the car cranks (the hipflex would send 11.5volts or so for a few seconds)

3- Could I drive the MC-E at 933mA per die (using 3 MC-E instead of 4 with the hipflex)?

Thanks for your help and soon the basics questions will be out of the way ;)

1- There's a few options, though none of them except for the P7 are very common. There's the SST-90, SST-50, Osram 6-die Ostar, SSC P7, Bridgelux, and maybe some other things.

2- To calculate voltage of series strings, multiply the vf of the LEDs by the number of LEDs in the string. I'm not sure what will happen on startup. Some buck converters will just let it dim, while others will self destruct. IIRC, buckpucks tend to self destruct. Don't know about the hipflex.

3- With very good heatsinking, sure. It's over spec but as long as you keep temperatures in control you should be fine.
 
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