diy water cooled cobs,first run ever.

[NastyN8t]

so I'm a newb with ambitious ideas . ......like all newbs.LOL

so I watched some of the DIY led guys throwing down with the white cobs and decided to try my hand at it .....most of my local comrade are disbelieving that a whit led can produce anything close to an hps without the red and blue leds emitting their particular wavelengths. I am determined to show them otherwise. So I built a balling on a budget set up using Chinese cobs and power supplies. I just got 250w running thru 4 100w Chinese cobs.powered by 2 125w printer power supplies. I have 6 more cobs and a 400w power supply on hand just haven't had time to assemble them yet......

 

[rob333]

so I'm a newb with ambitious ideas . ......like all newbs.LOL

so I watched some of the DIY led guys throwing down with the white cobs and decided to try my hand at it .....most of my local comrade are disbelieving that a whit led can produce anything close to an hps without the red and blue leds emitting their particular wavelengths. I am determined to show them otherwise. So I built a balling on a budget set up using Chinese cobs and power supplies. I just got 250w running thru 4 100w Chinese cobs.powered by 2 125w printer power supplies. I have 6 more cobs and a 400w power supply on hand just haven't had time to assemble them yet......

pics

 

[ttystikk]

Let's hear/see more about the water cooling bit, too. That sounds pretty sick if you can pull it off.

 

[NastyN8t]

so here's the plumbing rigged up to do a trial run. The bucket has a 630gph pump that is connected to the combo of pex and vinyl tubing.the block consist of a chunk of aluminum that I drilled a hole laterally thru directly under each 100w cob led. That flows under each cob and ends up back at the bucket after flowing thru a radiator with a fan on it .

 

[NastyN8t]

heres another

 

[ttystikk]

I like it, I like it!

 

[ttystikk]

Does it heat up the water when you run it? If so, how fast?

 

[NastyN8t]

it gets up around room temp + maybe 10-20 degrees Fahrenheit but idk how hot really.the room is maybe 6x8and 24/0 for10 days on, it stayed within5f of the temp outside. I plan on isolating the radiator in another room and using bigger fans with a bigger reservoir .

 

[ttystikk]

it gets up around room temp + maybe 10-20 degrees Fahrenheit but idk how hot really.the room is maybe 6x8and 24/0 for10 days on, it stayed within5f of the temp outside. I plan on isolating the radiator in another room and using bigger fans with a bigger reservoir .

Oh, I got me some ideas... did you just drill a hole in the aluminum block, or can you get a cooling coil for each COB?

 

[NastyN8t]

this is one cob when I was testing it on the printer power supply. Turns out that it was pushing 25w more than it was rated for. The cob started smoking LOL

 

[NastyN8t]

yeah just punched a hole under each cob.

I have a plan to cast an aluminum cooling block with a copper coil in the center of a parabolic reflectors

 

[DoctorDelta9]

Check out Craig's list. I found a 1/4 hp chiller for 150$. Once you get your cooling down. Maybe just run it through a chiller. Water+high voltage DC makes me nervous

 

[DoctorDelta9]

View attachment 3416357
so here's the plumbing rigged up to do a trial run. The bucket has a 630gph pump that is connected to the combo of pex and vinyl tubing.the block consist of a chunk of aluminum that I drilled a hole laterally thru directly under each 100w cob led. That flows under each cob and ends up back at the bucket after flowing thru a radiator with a fan on it .

Still trying to wrap my mind around this setup. A more lowpro approach might be to run the elbows from hole to hole (almost like and electrical setup in series) if you can find an efficient way to cool all that water (chiller) or maybe a small car radiator. I can see this being a good design. How did you drill those huge holes in the alum block??

 

[NastyN8t]

there is a radiator right above the bucket with a fan on it.....well actually its a heater core out of a car and a small PC server fan ....i thought of running the black elbows in series' but I didn't want one side of the block warmer or cooler than the other so I split the flow up equally. The block has 8 holes for 8 cobs but I was being rushed by my nagging woman and I fucked up on it...i used a craftsman 19.2v drill and some drill bits.

I used pieces of copper wire and laced the cobs to the aluminum block. I didn't have any time to drill and tap the bolt pattern from the cob into the aluminum. I could set it all up in a drill press and machinists vice to do it alot cleaner next time.

I've already got designs to uses 3" aluminum square tube thats about 4ft long with a cap and elbow plumbed on either side .I'll put 400-600w worth of cobs on it and run 2 or 3 of them on 9 plants.

I've got a bushy lil "big Sur "? Lady kinda scrogged out that I vegged under 100w t5 for like a month and a cheese clone. I've had them under the 250w water monster for about 2weeks. 1 week 24/0 1week12/12.

 

[NastyN8t]

the other night i threw a couple ice packs for a cooler in the bucket and it dropped the temps nicely.....when i start pushing alot more power ill use a large coller and fill it w ice packs. Should cool the room and lights untill the temperatures balance out. .......either way this set up is pretty cheap and could be replicated w basic hand tools and a drill.

 

[NastyN8t]

here's the original mock up . I decided that they need better spacing so I just hooked up 4 of them. 3 3000k and 1 6000k

 

[ttystikk]

This is the shit for cooling lots of hot COBs in a small space. How cold do they need to be to run efficiently? Would they run better at 55-60f than 85-120f? I know performance degrades as heat increases but I've never seen a graph.

 

[NastyN8t]

I was told 77f or 25c is the optimal range for cobs. I haven't measured the heat coming off of it but running 24/0 for ten days with the room 75-80f it was slightly warm to touch the block but definitely not hot. The radiator was blowing directly on the bucket reservoir too. The most expensive part of the plumbing was the fittings ranging from$.50-1.00 a pop. I did find some 3/8npt to 1/2 inch pex elbows for around $.50 that will eliminate the vinyl tubes at the block and be all pex except the flex lines from the pump. I'm thinking the next one should have some coiled garden hose instead that spiders out of a central manifold to each water block

 

[DoctorDelta9]

This is the shit for cooling lots of hot COBs in a small space. How cold do they need to be to run efficiently? Would they run better at 55-60f than 85-120f? I know performance degrades as heat increases but I've never seen a graph.

The efficiency decreases above 25C. Hence less lumens or PAR. @SupraSPL has done extensive research and his graphs are available under this fourm

 

[SupraSPL]

Yep, there are two considerations when it comes to LED junction temp,
-temp droop (immediate decrease in efficiency as temp rises)
-lumen depreciation (permanent decrease of efficiency over time)

White/blue LEDs are resistant to temp droop so you can run them hot (Tj 85C)with no major output loss. However, since efficiency has risen so high and cost has dropped, it is not hard to keep the COBs running cool (Tj 50C or less).

Vero29 temp droop based on case temp