slow LED build

A

aregias

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i've managed to source nichia LED COBs, NSCWJ216A, pretty cheap, 13$ each from a high CRI bin. Will they work well for lighting with dslrs?

Thinking of driving them at 36V 1.5A, finding it hard to get a decent heatsink.
I've calculated at 3.5 sq inch of heat transfer area per watt of LED, so for 200W, 700 sq. inches of fin surface area. actively cooled by a silent, slow fan.

Usually the heatsinks i have seen appear extruded, would i have to get extruded heatsinks or would i be able to manage with a 6mm copper baseplate and 2mm thick aluminum fins soldered to it?

This is going to take months. There will be many, many designs and redesigns, hopefully.





Adding a Cooler Master MegaFlow 200mm, heatsink will have to be square for now, but 100 cfm so maybe reduce the surface area of heat sink.


Resources:
Heat sink design, not too complicated https://www.aavid.com/sites/default/files/technical/papers/how-to-select-heatsink.pdf
 
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Can't you salvage some extruded CPU heatsinks from a junk computer shop?
If not, I'm sure that your copper idea would work great. I should think that the only reason copper isn't generally preferred over aluminum would be cost (and weight). It's a better heat conductor, right?

This sounds like a great project. Good luck!
 
From what i've read, though copper absorbs and transmits heat very quickly, it radiates out heat much slower than aluminum.Another idea i had was using a copper cylinder, make long slits into it and have thin aluminum fins. contained in a metal tube with an axial fan, too expensive to custom machine.
 
would they be powerful enough for 50W-70W LEDs?
the ambient temperature out here averages around 35C-40C.

Buying 10-15 LEDs. will try to make them modular if possible.

this is the only time i regret quitting engineering college.

The NSCWJ216A is rated for 70W max i think, would using a 50W driver just power it at a lower level or burn the driver?
AC-DC driver, not going for dimming, going to use scrims like HMIs, would that be effective?
 
How many LEDs would i need in an array to lose the multiple shadow effect? like the Hilio? 3x3 array
or just diffuse the LED emitters
 
Thanks guys, that makes a lot of sense.
Time to read up on more electronics.

The led is powered at 1A and 36V, if i'm driving it off a 12V battery all i need is a 12v to 36V dc-dc converter right?
and if i had to make it constant current, all i would have to do is use the appropriate resistors in the circuit.
do i need to look for any particular ratings for the battery?


150W DC-DC Boost Converter 10-32V to 12-35V 6A Step-Up Adjustable Power Supply is what i'm looking to buy.
And the battery is 12v 7AH would need a little extra power for the cooling fan.
 
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I design and build my own led lights for broadcast applications using mainly Cree leds. Be careful on the driver though, as some use the low frequency PWM for dimming and at certain camera framerates ( shutter speeds) may cause horizontal banding issues on the image which is impossible to fix in post editing. I build my own proprietary drivers from scratch that are rated to output 100 watts ( 36 v @ 3 amps) and take input DC voltages from 9 to 30 volts ( 6A max input @ 20 VDC). They are mainly being fed by Anton Bauer 14.4 broadcast bricks. I usually mix 2 color temperature types as I can control the color temperature from 2700K to 6500K just by mixing the dim levels of each set. As far as shadows are concerned, I use a flat diffuser that also widens up the beam and reduces glare, made by Bayer Makrolon Lumen XT in the LC-3 type.
I recently made a 1K equivalent unit ( 15,000 lumens) which measures 6 X 6 X 3 inches weighing less than 3 lbs. using only 9 Cree MT-G2's in the neutral 4000K bin. The key to this was an ultra silent Papst fan along with a custom driver that allows 0-100% dimming without banding issues. You can also check out fans by Noctua, but Papst is the king of silence. Ledil makes quality reflectors for large die leds.
 
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