Building a Cree Light for a 2x2 area. ( suggestions, thoughts, etc. )

Hi there,

I am in the middle of building a light for a 2x2 tent I plan on having and I already have the Idea and set up started. Basically I am using 4 3590 Cree's and will be mounting them to a 12' x 12" 1/4 thick piece of Aluminum Plate and using 4 heatsinks with fans connected to the other side. I know it's different than most I have seen.

Parts already bought.
$20 (1) Solid Aluminum Plate 12"x 12" 6061 type
$51.68 (1) 2700K BB Cree COB CXA 36v
$72.94 (1) 709-HLG240H-C1750A Meanwell 250 watts 1.7A Driver
$11.00 (4)Ideal Chip Lok 3590 Holder
$7.96 (4) Ideal Reflector Adapter for 3590
$13.00 (4) Ledil Angelina Reflector F13838 (Ideal System Version)
$34.95 (5) Cooler Master DP6-9EDSA-0L-GP CPU Air Cooler
$125.97 (3) Cree CXB 3590 3500K CD 36v
$12.00 (2) Ratchet Hanger Set

Total $351.50 & $32 Shipping = $383.50

It will run at these numbers @ 50C.

3x 3590 CXB CD w/ 1x 3590 CXA BB , 1.75 A (max)
249.2 Watts
36,346.4 Lumens
142.4 Volts
146.225 lm/W

Still waiting on some ship delay parts atm I bought the plate as something to play with basically while I wait.

Next I will look for a power supply for the fans.

Here is a look at the plate with the Led Holders and Driver on it to get an Idea of size.


I have already started using steel wool to run down the corners flat where the lights will be.

Here is the bottom of the heatsinks I will place on the other side of the aluminum plate right on top of the chips. They have 92 mm fans and are about 92mm or so in diameter and the cooling rating is 82w. My biggest question right now is how well will those heatsinks pull heat straight up through the plate. If each chip at is using 62 watts 40 or so of that will be heat watts? When I get this done later this month I am going to give this a shot at 1 amp or so and see how it works first before even thinking of jacking the amps all the way up.

Has anyone tried this yet?

specs: https://www.rosch-computer.de/datasheets/product/CPU%20L%FCfter/DP6-9EDSA-0L-GP.pdf

You are spreading the heat way out before it sees a heatsink, which only has a cooling area about the size of a cpu. If I had to guess I'd say it's a terrible idea. Like, super terrible.

Mount those cobs on the coolers, if they will fit. If not, buy different coolers.

JorgeGonzales said:

You are spreading the heat way out before it sees a heatsink, which only has a cooling area about the size of a cpu. If I had to guess I'd say it's a terrible idea. Like, super terrible.

Click to expand...

Don't worry I will turn this down real low and test long before I ever turn it up and see how it works with the plate.

I will get a heat laser to check things out.

Ok the fans came in and I just set them on the plate with the Driver for a look. Still have a couple weeks to go for the cobs...

You could calculate the resistance of the metal sheeting along with the mass of cpu coolers....then calculate against the resistance of the thermal interface material you will use...

I would say if mounting this way, make sure the bond is very good between cpu cooler and metal plate. It will act as a giant heatsink if it all transfers correctly.

Have you done any thermal modeling before? Kinda helps before you drop $4 bills on something you won't/ haven't even read up on.

Oh yeah, I have been reading for a couple weeks now in depth, I will be polishing the surfaces with ultra fine until I can get as close to mirror finishes as I can. I have already looked at the amount I need total and what each fan would have to cover and added up all the fins surface area they should be plenty enough to pull heat from the spot the chip is on. I figured everything from max power usage 250w 1750mA which I will probably not be using I figure I will be using 1-1.4A when all is said and done. I am ordering a thermal heat gun and will be testing at 50% ( .875 ) amps and slowly moving up in power while measuring to find the spot where 45C-50C will be the average temperature when everything is warmed up. The Main thing will be the mounting surfaces being right and finding those temperatures and amps that I can use with this set up.

I have built my own water cooled computer so I do have some understanding of heat and keeping things cool. With the computer you do a lot of testing to find the right Settings to max CPU usage and keep temps at acceptable levels. I will be doing the same here pretty much.

The Power supply will be mounted on grommets and higher than the plate to keep airflow moving over the plate from the fans. I am also thinking about drilling holes under the power supply as sort of a convection air flow coming up through the bottom of the plate.

Still reading and thinking,...

I've seen and used the aluminum plate in the middle before. It creates an extra step and you'll use a bit more thermal adhesive paste but it seemed to work fine. I've actually got a 4'x4' sheet in my garage waiting for the next custom build.
I put standard extruded heatsinks on the back though.

I have 4cxb 3590 at 1.4a in a 2x2.5 tent

https://www.rollitup.org/t/4-cob-diy-build.899905/

Bachomp said:

I have 4cxb 3590 at 1.4a in a 2x2.5 tent

https://www.rollitup.org/t/4-cob-diy-build.899905/

Click to expand...

Looks good!

Ok I have a start going for the plate atm I threaded all the holes and used brass screws. Here are a few pics with just the holders and reflectors on.

I am thinking about drilling some holes under the power supply as it will be raised off the plate some.

Here is an image I made up with holes drilled...do you think this would help with cooling the power supply?

Fans will be pushing air across this area from 4 directions.

Have you considered using some additional leds such as Deep Red, IR and Far Red? During build you can add these to your setup with additional drivers from meanwell lpc-35-700 to drive up to 15 leds, five of each color. IR helps trichrome development, Deep red helps develop size and stretch, and Far red puts them to sleep at night after lights out. peace.
https://www.rollitup.org/t/the-far-red-thread.867665/

One of those cobs is not like the others, one of those cobs is not the same.... Can you tell which one?

BTW there is no need to cool the power supply, but it wont hurt to drill extra holes, unless you wanna mount a center cob down the road....

VegasWinner said:

Have you considered using some additional leds such as Deep Red, IR and Far Red? During build you can add these to your setup with additional drivers from meanwell lpc-35-700 to drive up to 15 leds, five of each color. IR helps trichrome development, Deep red helps develop size and stretch, and Far red puts them to sleep at night after lights out. peace.
https://www.rollitup.org/t/the-far-red-thread.867665/

Click to expand...

Yeah I have thought about it and maybe after I get this one built and tested I will consider doing that.

thetr33man said:

BTW there is no need to cool the power supply, but it wont hurt to drill extra holes, unless you wanna mount a center cob down the road....

Click to expand...

Well what I am thinking is it will give some kind of convection cooling in the middle there and might actually help a little.

"One of those cobs is not like the others, one of those cobs is not the same.... Can you tell which one?"

Yeah they are different colors the 2700k is more orange yellow.

ohhhh... I got it up and running! so far so good. It's not a thing of beauty, but it definitely is bright as hell! .

I will rig it up in the tent later just to see how it looks. I can't believe you put those lights 18 inches from the plants?

I just mounted the power supply right on the plate for now doesnt seem to get hot at all.

So far I have turned it up to only 50% which is around 1300 mA (875 ~ 1750mA ) 190w.

I think that's about 29k lumens total there.

Ohhh yeah had on oops moment there where I stuck my finger in a fan and broke a blade off.....sob was spinning 2000 rpm's lol......glad I bought 5!

Here is a couple pics...of the test build....

Ok we have Lights! Right now I am testing at the lowest Amps, 875 mA, for a few hours and seeing how hot the plate gets and around the led and fans. It's 26C in the house and the initial reading after turning on the light for a few mins were in the 27-29C range. Closing the tent atm is not going to work with no exhaust hooked up and temps went up fast to 31C or so.

Here a a couple pictures of the light in the tent running! one with flash one with auto camera.

I pointed the two fans up rather than down and left the very edge of the door upzipped and pulled the 6 inch roof exhaust port up like a chimney to let hot air escape.

Well the first test went so well I bumped it back up to around 1300mA and left it there. for a couple hours or so now.

It's scorching hot in the house 89 F atm I went and took a nap and came back lights are still kicking it strong.tent is at 93 F.

The temps...

AT 875 mA and 88 F in the tent plate was about 32C on top and 34C on bottom. fans ran about 37-40C and driver was at 36C

Right now at 1.3 mA and 93 F in the tent we have the plate top at 34C, the bottom 36C, Driver at 38C, center of fans at 38-41C.

I think it's doing pretty good considering the ambient temps in here atm...tent is by the front window full of sun right now.