Unread 05-20-2010, 10:53 AM
blasterman blasterman is offline
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Join Date: Jul 2008
Posts: 993
Default Re: Review: Satistronics 20watt blue LED
I did run into some issues with the big Satistronics, but they were more interesting than anything else.
First, the color isn't as deep as their 3watt LEDs. Satistronics 3W LEDs are nearly identical to royal blue Crees, but about 25% less bright. I thought the 20watt versions would be the same color, but they aren't. They are between RB and standard blue Crees, which is very Cyan. While not a show stopper, about 90% of us prefer royal blue for reefing.
Another issue is the 20watt version when fired up to full power are rather dangerous to use. First, they are a terror on your eyes and worse than 400watt reef metal halide. Next, they'll ignite any object placed within a few inches and will burn through plastic in a matter of seconds. Since I like to use acrylic covers over my tanks this created a problem. Setting a fire with a LED like a laser is actually kind of fun at first, but then there's the issue of trying to epoxy optics over an emitter that does this. The epoxy soon melts.
So, the 20watts are sitting in a box waiting for another project. In the mean time I contacted Satistronics, and they said they'd look at making a 440nm blue in 10-20watts, which should solve the problem. Color will be awesome for reefing and green-houses, and at 10watt it will eliminate the need for 3watt RB Crees.
As for power supplies, I use both LED current regulated and fixed voltage. In most cases I don't need current regulated and fixed voltage supplies are typically cheaper, but a tad less efficient.
For instance, I have a box full of 18.5 volt 6.5amp laptop bricks. I run 5 white or blue LEDS in series, and this delivers 3.7 (3watts) to each. No need for resistors. I just keep throwing a series of 5 to get my light value. Real easy.
A fixed voltage Mean Well typically has a voltage adjustment range, and this is certainly more flexible than a laptop brick because you can tweak the voltage to match what you want to do. Also, Mean Wells are cheaper and better made than laptop bricks. However, I've got that case of laptop bricks so I might as well use them. Plus, laptop bricks are sealed and won't die if a splatter of salt gets in them.
Oh yeah, one piece of advice for reef lighting. If you want better color, don't use cool-whites. Use neutral-whites instead at about a 2:1 ratio of RB/neutral-white. I've been following the crowd on cool-whites and not getting good color in my tanks, and on a hunch switched to neutrals. I got much better color, with more purple/pink/orange. If you don't believe me, just try two RBs with a neutral in between them and hold it over a part of your tank. The color improvement over cool-whites is impressive.
