diy multichip led lights

[Floyd R Turbo]

Yeah I guess I keep thinking analog dimming and don't know why...

[nige]

Someone on our local site posted this



I have to imagine that there is some truth to this. cooling a 100W LED chip would be a difficult task I would think. I would think that the need for dimming would be crucial to take care of the coral bleaching aspect. So I wonder how you would go about dimming large LED like this, would there be any different considerations being that it is a multi-chip LED? Meaning, since you have more than one chip on the board, if you simply supply less current would you get less output, in the same fashion as if you had an equivalent string of 3W chips?

I have been running these about 3 months now and so far so good I did have a problem with the centre led heating but I just fitted 2 extra fans either side of the heat sink to help disperse the heat I put this down to the components restricting the air flow now they run cool 45deg c so just warm to the touch but not excessive there are oil cooled heat sink available that aren't that expensive and the orphek lights don't even use fans or liquid just a big heat sink.but will add if a fan stops they will burn out in a short time as they heat up really quick.

[nige]

as for bleaching the only thing I had a problem with was green buttons but I just raised the lights higher up and they coloured up again but I will keep you all updated on the progress of this lighting and if I run into problems I will let you all know but so far they have been a great success

[kerry]

It is a very impressive light for sure!!!

[joelespinoza]

I have to imagine that there is some truth to this. Cooling a 100W LED chip would be a difficult task I would think.

No more difficult then cooling high end CPUs and GPUs. Worst case scenario is watercooling, and lets face it, we do aquariums, a bit of plumbing and a few pumps are nothing new. Somewhere on the reefcentral multichip LED forum post I outlined a watercooling build you could do that made use of small aluminum civc radiator off ebay and individual water blocks. It would be HUGE overkill for most tanks, but if you had a very large tank it could be useful. Especially since you can remote mount water cooling radiators, so you could toss it in the basement, or even outside, which could be a HUGE energy saver on very large builds.

1 hp = 746 watts

Now I realize there are efficency percentaqges, windspeed, radiant heat etc, that I am not even going to try to worry about. However I have personally seen 400hp+ honda civics running on the stock radiator, the one linked below is an upgraded model:

Aluminum "racing" radiator $57.20: http://www.ebay.com/itm/Dual-Core-Ho...478c3e&vxp=mtr

7" 12v fan $22: http://www.ebay.com/itm/SLIM-7-PULL-...5e3f65&vxp=mtr

Now would I trust this to dissipate 373,000 watts of LED power (500 hp x 746 = watts), like I would in a racing civic? Ehhh probably not quite. But I think you get the point.

Meaning, since you have more than one chip on the board, if you simply supply less current would you get less output, in the same fashion as if you had an equivalent string of 3W chips?

As was mentioned, there are better ways of making dimming controllers, but you can certainly underdrive them that way. In fact it was pointed out in the reefcentral forum on this same topic that some of these "100" watt chips are actually ~100 2-3 watt emitters. So it is possible to juice them up to 250 watts as long as you take care of cooling.

Here is the RC thread on this, it has been going quite a while with tons of pics wtc: http://www.reefcentral.com/forums/sh....php?t=2128756

[srusso]

SatisLED.com sells dimmable 50w and 100w drivers...

[Floyd R Turbo]

Are they PWM dimmable, or just by an external potentiometer? ac-rc on ebay has those also. I'm heavy into the RC thread on this right now LOL

[srusso]

external potentiometer....

[Floyd R Turbo]

I just found out some good info from TheFishMan65 on RC. He's the one that makes a CAT4101 board that can drive up to 160W of LEDs, 8 strings of 6 3W chips each on a single driver, with PWM dimming, each string can be 25V total drop and 1000mA current. But you can tie 2 strings together and get a 2000mA string. So now I can take one 160W+ driver and one of his boards, and run 2 20W chips in series on a double-leg, and run 8 20W chips off one driver, and have them under full PWM dimming control.

So now that I know that, I've got to figure up which option is better, from all angles. Got the go-ahead from one of my customers to price out a few options, so I'm going to figure up that one, then a 3W array, and possibly one option with the 100W chips but I don't think that will go too far, who knows.

Right now I'm thinking of doing a 16 chip array, and I would have 8 legs of PWM dimming. Awesomeness factor 9.7.