Minimalistic multichip DIY LED build

First of all your English is excellent! On top of that your step by step instructions are superb, I can wait to see your next video! Have you or have you heard of anyone supplementing the multi chips with single chips like Royal blue for accent lighting? I wonder if you can use multi chips to get a spot light effect like how many Japanese Reefers use PAR 38 lights. I really like the shadow effects you can get with PAR 38......

Thanks again for a first class DIY video!! -Mark
 
Thanks guys! :)

Yes you can definitely use lenses with a tight beam to get accent lighting. A reefer I know back in Sweden has created a tank with a single reef pillar with sps. The whole tank is dark except for the lighted pillar.

I have not seen ppl using single chips for accent though, but I have seen people using 10W RB's for that.
 
BTW, this is a close up of one of my multi chips, you can see how the individual LED's are connected in both parallell and series into something like a grid.

 
Question, the rule of thumb for 3w leds is L X W / +-16 to find the number of leds you will need. How do you figure the number of multi chip leds you will need on your tank?---Rick
 
Great video!! A few questions about your heatsinks and leds. First, I had been looking at these leds before and I never found out if they are rated at their actual wattage or equivalent wattage. For example, on ebay, the 100w chips have a forward voltage of 36vdc. Does this mean they are 100w equivalent? Also, where did you find those active heatsinks? Are they overkill? Thanks
 
Rick! I would say basically the same formula, just keep in mind that you have to figure out what wattage the individual LED's have and adjust the formula accordingly.

For example the 50W LED's are built by 50 x 1W LED's. The one's I'm calling "100W multichip" are built by a hundred LED's that can go from about 1W to 2,5W each.

So for example 24"x12"/16=18 18x3W=54W Okay, for this tank i would go with smaller multichips perhaps 8x10W or 4x20W and just dim them down a little.

Or for a 48"x22"/16=66 66x3W=198W So I would go for 4X50W mixed cool white/rb and probably 4x10 pure RB to use as dawn/twilight lights.
 
maglofster said:
Rick! I would say basically the same formula, just keep in mind that you have to figure out what wattage the individual LED's have and adjust the formula accordingly.

For example the 50W LED's are built by 50 x 1W LED's. The one's I'm calling "100W multichip" are built by a hundred LED's that can go from about 1W to 2,5W each.

So for example 24"x12"/16=18 18x3W=54W Okay, for this tank i would go with smaller multichips perhaps 8x10W or 4x20W and just dim them down a little.

Or for a 48"x22"/16=66 66x3W=198W So I would go for 4X50W mixed cool white/rb and probably 4x10 pure RB to use as dawn/twilight lights.
Click to expand...

I see, makes sense. Thanks
 
Phishguy said:
Great video!! A few questions about your heatsinks and leds. First, I had been looking at these leds before and I never found out if they are rated at their actual wattage or equivalent wattage. For example, on ebay, the 100w chips have a forward voltage of 36vdc. Does this mean they are 100w equivalent? Also, where did you find those active heatsinks? Are they overkill? Thanks
Click to expand...

Thanks!

Well about the rating of the LED's. It's a mess.. :) The ones they call 100W actually consist of 100 individual LED's that can be driven from 1W up to about 2,5W but they still call it 100W.

The multichip I'm using (the large 100W) have a Vf of about 36V and a maximum current of 7A. So to calculate wattage I use the formula P=U*I. P=36*7. P=252. So 252W and if you divide that with the number of LED's you get the individual LED wattage 252/100=2,52W.

Im going to drive mine at about 175W i think. That would give me a wattage of about 350W over my 40"x40" tank which is 24" high. During peak hours I will also add an extra 100W 10K white. It may be to high, but we'll see.
 
maglofster said:
Or for a 48"x22"/16=66 66x3W=198W So I would go for 4X50W mixed cool white/rb and probably 4x10 pure RB to use as dawn/twilight lights.
Click to expand...

For the 4x50w and 4x10w, its 240w total vs. 198w. Should you figure a higher total wattage on the multi-chip and then dim to your desired wattage?
How do you decide on the proper spacing/location of your chips? Thanks Again,---Rick
 
I was thinking of using the RB's (4x10) only during dusk/dawn to create a blue light only. Not during "daytime". Just control them with a timer.

For spacing, try to just calculate an even distance between the lights and put them in a row over the middle line of the tank. To cool the 10W lights you won't need VGA CPU coolers. Just use passive aluminium heatsinks. Maybe a thin long one that you easily can hang up over the tank.

About the total wattage being a bit higher, don't worry. The LED's have a bit lower efficiency than the Cree ones. Maybe use a formula like: L*W/14 which gives (48*22/13)*3=243. But this is not scientific at all. We dont have enough facts and knowledge of the multichips yet.

Over my Elos tank, 48" by 22" I use about 280W LED's right now.
 
Last edited:
I see, Thanks,
For lenses should I use the same as if I were using 3w leds? I was going to use 60 degree as the leds will be mounted in my hood, with a distance of 10" between the top of hood to top of water.
 
007Bond said:
I see, Thanks,
For lenses should I use the same as if I were using 3w leds? I was going to use 60 degree as the leds will be mounted in my hood, with a distance of 8" between the top of hood to top of water.
Click to expand...

Yes, I would say not any tighter beam than 60 degrees or you will get the ol' Disco effect.. :) And yeah, dont use lenses for the 10W's if you decide to use them, it will be nicer with a very diffuse blue light I think.

This will take care of the 50W cooling: http://www.arctic.ac/en/p/cooling/vga/425/accelero-l2-plus.html?c=2182
 
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