I started a thread a little while ago about calculating junction temperatures for an array of LEDs, and I thought that I'd post up the nearly completed project that spawned the question:
The project started while I was at work wiring a new house one day (I'm an Electrician). The house didn't have an electrical service to it yet, so the site was being run off of a generator. At this time of year it stays dark late into the morning, and gets dark again early in the evening. The added load of floodlights to the usual drills and saws and whatnot was taxing the generator, tripping the breakers often. I decided to turn my $5.00 500W floodlight into a very expensive but much more efficient light. (Going from 5A to 0.5A on the 120V side)
This is the result:
I used 30 Luxeon Rebels pre mounted to 10mm square boards, 5650k running 135lm each @ 350mA for a total of 4050lm. I used a Philips Xitanium 40W 1750mA driver to power them. They are all mounted to a 13cm x 7cm 1.4ºC/W heatsink. The center LEDs have a 50º optic attached to them. I had optics for all of the boards, however there was not enough flood with them all attached. I've also got a 105ºC thermal switch wired in series with the LEDs and attached to the heatsink as a safety, as this was a wee bit expensive.
All I've got left to do is figure out a clean way to seal off the face of the heatsink from the bowl of the light, because I don't want moisture and dust coating the LEDs from the ventilation holes I had to drill into it.
I'll post comparison pictures against another 500W flood I have once it gets dark tonight.
Sorry the pictures are sideways, I'm having trouble getting them to stay rotated.
The project started while I was at work wiring a new house one day (I'm an Electrician). The house didn't have an electrical service to it yet, so the site was being run off of a generator. At this time of year it stays dark late into the morning, and gets dark again early in the evening. The added load of floodlights to the usual drills and saws and whatnot was taxing the generator, tripping the breakers often. I decided to turn my $5.00 500W floodlight into a very expensive but much more efficient light. (Going from 5A to 0.5A on the 120V side)
This is the result:
I used 30 Luxeon Rebels pre mounted to 10mm square boards, 5650k running 135lm each @ 350mA for a total of 4050lm. I used a Philips Xitanium 40W 1750mA driver to power them. They are all mounted to a 13cm x 7cm 1.4ºC/W heatsink. The center LEDs have a 50º optic attached to them. I had optics for all of the boards, however there was not enough flood with them all attached. I've also got a 105ºC thermal switch wired in series with the LEDs and attached to the heatsink as a safety, as this was a wee bit expensive.
All I've got left to do is figure out a clean way to seal off the face of the heatsink from the bowl of the light, because I don't want moisture and dust coating the LEDs from the ventilation holes I had to drill into it.
I'll post comparison pictures against another 500W flood I have once it gets dark tonight.
Sorry the pictures are sideways, I'm having trouble getting them to stay rotated.