Group Buy: 220W Multichip LED Cooler

[007Bond]

Thanks Ron, That is the input I was looking for, I plan to experiment some. I was also planning on a thermocouple to cut power to the chip if heat should reach unsafe running conditions. On the AC-RC site, looks like they had the chip at 6+ amps on their cooler, but I don't know for how long of a duration they ran it. Like I posted I'll watch for the par tests from AC-RC you asked them to do. I hope they show different currents at different depths. 120cm in my case.---Rick

[tentacles]

Well guys I had a chance to test the 60w multichip with the heat spreader, and it actually did help temps. A lot- full load with fan on full, before was ~67-69C, and now it's more like 46C. I used a 1/4" plate of copper (C110 alloy, pure electrical copper) and it ended up more like 6mm after machining. I suspect that you could use bar stock as it comes from somewhere like onlinemetals, maybe with a light sanding to take off any burs. I used arctic silver (silver) epoxy to glue the heatplate to the heatsink and then arctic silver alumina paste between the emitter and the copper plate. I didn't pay enough attention while gluing the spreader on, though, and it ended up off center! @%$#%(!!!

Rick, I am going to use thermal switches to protect my lights. They're like $1 each on ebay and can handle 5A. It's basically a preset thermostat, so when the temperature exceeds 70C, they switch off until it cools down 20-30C according to the listing. I plan to put one on each channel directly at the emitter. Another option may be to use 3 @ 70C and 1 @65C, so maybe a white channel pops off and stays off if it gets too hot, then the whole fixture will cool down somewhat but likely not enough for the 65C channel to kick back on. You'd notice your tank bein too blue, I think. http://www.ebay.com/itm/160863183164...84.m1423.l2649

edit: One more thing we all need to keep in mind is some headroom - if your cooling solution at it's best can only just keep it under the limit, how much dust will it take to cook your chip?

[007Bond]

Well guys I had a chance to test the 60w multichip with the heat spreader, and it actually did help temps. A lot- full load with fan on full, before was ~67-69C, and now it's more like 46C. I used a 1/4" plate of copper (C110 alloy, pure electrical copper) and it ended up more like 6mm after machining. I suspect that you could use bar stock as it comes from somewhere like onlinemetals, maybe with a light sanding to take off any burs. I used arctic silver (silver) epoxy to glue the heatplate to the heatsink and then arctic silver alumina paste between the emitter and the copper plate. I didn't pay enough attention while gluing the spreader on, though, and it ended up off center! @%$#%(!!!

Rick, I am going to use thermal switches to protect my lights. They're like $1 each on ebay and can handle 5A. It's basically a preset thermostat, so when the temperature exceeds 70C, they switch off until it cools down 20-30C according to the listing. I plan to put one on each channel directly at the emitter. Another option may be to use 3 @ 70C and 1 @65C, so maybe a white channel pops off and stays off if it gets too hot, then the whole fixture will cool down somewhat but likely not enough for the 65C channel to kick back on. You'd notice your tank bein too blue, I think. http://www.ebay.com/itm/160863183164...84.m1423.l2649

edit: One more thing we all need to keep in mind is some headroom - if your cooling solution at it's best can only just keep it under the limit, how much dust will it take to cook your chip?

Tentacles,
What is the max wattage you can push your 60w chip? 20 degree drop is big! This is the first I have heard of plates attached to cooler plates. I wonder why all cooler makers don't supply plates with their coolers? Why did you glue instead of bolting the plate to your cooler? I see how with cooler plates in most cases can not be drilled, sure would be nice if manufactures would provide holes for attachments if wanted.

Your thermal protection is what I was planning. I was thinking of using 1 that would cut power to all drivers, thus complete shutdown. May be two is series.(redundancy). I was wondering about the thermal temp. spread between shutdown and restart, I was afraid it would start cycling. My fear is fan failure. I think your headroom statement is important in all the parts of your build. Thanks for the input, seems like every time I think I have things figured out, I read the next post... and its back to the drawing board.---Rick

[gtfcniles]

No need to have one of them on your fan circuit only on led circuit

[007Bond]

Maybe I did not explain correctly. The thermalcouple will be at the coolers plate of attachment of the chip. If heat goes above 70c I plan to shut my drivers off temporary.---Rick

[tentacles]

Rick, I can push the full 150w to the 60w multichip. (HLG150-36B)

All the plate does is spread the heat out a bit better, I am honestly surprised it did anything at all, and in fact it could be that the silicone thermal glue I got from ac-rc is really just that much worse than the arctic silver products.. I didn't want to be popping glue joints off a bunch so I didn't try, don't want to risk bending/damaging the multichip. I will probably pop the heat spreader off and reposition it, though.
(t
Instead of a thermocouple I am going to be using a reef angel compatible temperature sensor in my builds. It's a DS18B20 temperature sensor, I got some for $2 each on ebay.

[007Bond]

T, Thanks for the input.---Rick

[acabgd]

I'm pretty limited in what coolers I might get locally here. Could you please advise if one of these might be sufficient?

http://www.gigatronshop.com/kuleri/c...-13fk-r1-15181
http://www.gigatronshop.com/kuleri/c...-13fk-r1-14821

Thanks,
Alex

[tentacles]

The second one, hyper 612 is definitely enough equipment for the job.. the first one likely is, but I'd have to see benchmarks to be sure.

[Lasse]

Rick, I can push the full 150w to the 60w multichip. (HLG150-36B)

All the plate does is spread the heat out a bit better, I am honestly surprised it did anything at all, and in fact it could be that the silicone thermal glue I got from ac-rc is really just that much worse than the arctic silver products.. I didn't want to be popping glue joints off a bunch so I didn't try, don't want to risk bending/damaging the multichip. I will probably pop the heat spreader off and reposition it, though.

I also because I did not think that it should work that way when you use heatpipes and get a rather huge temperature different between the cooler base and the backplate of the chip. Could it be the differences between the thermal compounds? However - probably I´m going to use a plate but in order to bult the plate to the cooler and bult the chip to the plate. I have 1 pcs of 100 watts chip that had been glued to a coolerplate but after a short period of overheating (no dammage to the chip) it just get lose.

Another question I´ll try to post some pictures here but I can´t find a way to attach any files at this board. anyone knows how to do?

Sincerely Lasse

[Lasse]

@ Tentacles. I´m testing a 50 watts 45 mil multichip just now with Zalman VF900-CU. Chip clued to the coolerplate with artic silver glue. At 3A - 35,3 - 105 W - temp at the backplate - 42 degree C. Fan high; 2.5 A - 33,9 V - 85 W ->temp 39 C, fan high. Fan low -> 48 C; At 1.7 A - 32 V - 55 W Fan high -> 32 C; fan low -> 37 C

Sincerely Lasse

Some pictures












It was tentacle or tomservo who give me the idea - I do not remeber who - but - thank you

[tentacles]

Same person! No problem, I was hoping it would be useful for someone else as well. I was working on the 60w one today, I popped off the heatplate to move it, was able to neatly scrape the Arctic silver epoxy with the use of a heat gun (300C setting) and a razor. I glued it back on and then made little covers for the finless spaces as a lot of air was being wasted there. Also sanded the outside of the PVC fitting and painted it with gloss black fusion paint. I'd take some new heat readings but as I don't want to mess up the paint job (still too soft to handle) the readings with the heatsink outside of the casing wouldn't be comparable to inside.

Those are some nice numbers Lasse, it's probably the heatpipes, they really make a huge difference in a heatsink's capability. The dream chip versions I will be making will use the CNPS8900 Extreme heatsink that has 2 dual-ended heatpipes. It's a bit too big to fit in my 4" coupler so I will machine them a bit to make it fit.

[007Bond]

Same person! No problem, I was hoping it would be useful for someone else as well. I was working on the 60w one today, I popped off the heatplate to move it, was able to neatly scrape the Arctic silver epoxy with the use of a heat gun (300C setting) and a razor. I glued it back on and then made little covers for the finless spaces as a lot of air was being wasted there. Also sanded the outside of the PVC fitting and painted it with gloss black fusion paint. I'd take some new heat readings but as I don't want to mess up the paint job (still too soft to handle) the readings with the heatsink outside of the casing wouldn't be comparable to inside.

Those are some nice numbers Lasse, it's probably the heatpipes, they really make a huge difference in a heatsink's capability. The dream chip versions I will be making will use the CNPS8900 Extreme heatsink that has 2 dual-ended heatpipes. It's a bit too big to fit in my 4" coupler so I will machine them a bit to make it fit.

Tom, I just looked at FrostyTech report on the CNPS8900 Extreme. Their test was at 125w = 17.2c, dose that mean you would double the number to 250w would equal 34.4+-c in temp. for the Dream Chip?---Rick

[tentacles]

It's hard to say, Rick, I suspect with heat pipes the numbers won't be linear.. I'll plot it up real quick in Excel and see what is what.. Well it's definitely not increasing linearly, but with only 3 data points it's hard to say. My thinking has been that the normal way to use a dream chip is not at 100% on all channels..

Looking at my chart I'd say temp of +40C over ambient is likely at a full 250w, which in many cases would keep it under 70C but it's unlikely to be driven so hard over most tanks.

[007Bond]

Thanks Tom, That looks like a good cooler, and high marks from Frosty Tech. 40C at full bore is still a long ways from the 70c danger mark. My tank is aprox. 42" deep, so I'll most likely will be pushing a little harder than most. I'll need to factor in if I can use optics or not, but I don't have mush room between the water and the top of my hood, so I'm not sure yet.---Rick