My custom 1K battery powered LED

Norman99

Norman99

Well-known member
Finally finished and tested my DIY battery operated ( V mount 14.4V DC ) led project.
Just need a few opinions of it for possible improvement (s).
here are the specs:

Measures 12 X 6 X 3 inches
Weighs in without battery at 4.8 lbs
Power draw at full brightness is 72 watts
Passive thermal design ( no fan )
120 watt/hour battery lasts 90 minutes
Leds are the latest binned 5200K with well over 100 lumens per watt at rated full brightness
TIR optics as pictured are 12 degree spot ( interchangeable for 24, 35, 40 degrees )
Dimming is non PWM for flicker free non banding type.
4 pin XLR input for DC or AC operation
Input DC voltage range from 12 to 24 volts
Diffusion panel fits into grooved front slot in front of polycarbonate protector
21,000 lux @ 3m ( 12 deg, optics)
Weather sealed with high temp silicone gasketing
Mil spec potentiometers, teflon wiring throughout.

IMG_4749.JPGIMG_4750.JPGIMG_4752.JPG
 
Output is exactly 21,000 lux at 10 feet away. Measured with incident light meter.
The beam is narrow but can be easily diffused using an umbrella or a diffusion screen/panel
The leds aren't even running at their full potential of 10W each but throttled down to 60% to enable passive heat management. With a fan next to the battery plate, I can run them at full pop to 30,000 lux but losing efficiency and not worth the extra luxes gained. 6 W per led seems to be the sweet spot for fanless operation. I plan on doing a twin led per optic design pretty soon using 12 optics with 2 leds per optic for a 3200K-4000K-5200K selector, along with a remote phosphor design in the near future.
 
I see it for remote locations where a generator is not practical and where complete silence is needed. A Makrolon Lumen XT diffusion panel will be tried on it as to allow a superwide beam spread of 80 degrees ( losing around 2.5 stops in the process ). I will post resultant lux readings as soon as I get a hold of it. I will try to get a night shot of a house located 100 feet away and see what happens later on this week. I will take a picture noting aperture,asa and shutterspeed with my Canon 5D.
 
If a 1K means 1000 watt filament tungsten which is around 18,000 lumens, then my measurement of a spot area projection at 10 feet @ 12 degree beam is according to my measurements, using a Gossen MultiPro Lux meter ( incident ), would be brighter by 15% more than a 1K. That also depends what you mean by a full spot. A 1K fresnel at full spot of 10 degrees or less would be brighter. Comparing the same spot degree of a fresnel vs my led, I would say they would appear equal brightness to the eye but actual photometric measurements would dictate a difference so slight that would be in the 1/8 stop range. I don't have a 1K fresnel to do any comparison testing but I am basing that 1K luminosity at 18K lumens as the total radiated light. Lumens and LUX are different beasts, and require a different mode of measurements, but when actual incident measurements are taken either on a LUX or EV scale at the SAME distance and at the SAME beam angle, then we can have a true reference of brightness.
 
You left out the most important part: what model LED are they? is there a green cast that needs correcting? does it produce the rated kelvin? and does it have a high CRI? i did a DIY 100w spot which i never finished tinkering with, and when i was shopping for that chip, the options in the 100lumens/watt had poorish CRI. but then again that's for 100w chips, never looked at the 6w variants.

where in NY are you? i'm up in astoria, and my living room is in shooting studio mode for some client stuff this week and the next. and i have various other lights including 1k 8" fresnels to compare with.
 
The leds are Cree XM-L2 variety and NOT the earlier XM-L's. The ones I use are hand picked from the same bin and are measured to be 5150K. Color meters are useless in led color determination . The 100 watt led you used is most likely in the 60 ish lumens per watt variety WHEN DRIVEN AT 100 watts. The XM-L2's are OVER 100 lumens per watt at the full rated 10 watts. CRI figures are really meaningless when it comes to actual eye perception and can be misleading. I have tried 90 CRI leds compared to the same color temperature ones of 80 CRI and did not notice any visual color difference. There is NO green cast in these. This is a DIY project and I am keeping the driver circuitry confidential as it is a specially designed unit of 92% efficiency when input is 12-15 VDC. These leds are not 6w variants, they are 10 watt emitters of the Lighting Class variety. I reduce the amperage and wattage to 6W as to enable passive cooling. A single 100 watt led is a great idea for fresnel use and single shadow, but when they come in the 100 lumen/watt variety then I will consider them.
 
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