Lighting 1 cob led light help

[CoviklaFlaire]

I left with one citizen 1212 3500k 90 cri, and i ordered single driver for it, now the thing is i got this old bad ass zalman cpu cooler

and i wanna put led on it ...
Now I wanna know is it doable..and any suggestion will be highly appreciated..

 

[wwwillie]

Should work just fine.
Here is a picture of a PC heat sink COB I made.

And here is more PC heat sinks with some Chinese self driven COBs.

Here it is all wired up and ready to fire.

From the top.

From the side.

Lit up and looking bright. Had to pump a ton of flash at it to get a good shot.

All the bits I used to make it. You can see the motherboard bracket bit and the heatsink goop on the CPU cooler. The COB pcbs are a great fit.

 

[CoviklaFlaire]

Beautiful..Thanks dude!

 

[CoviklaFlaire]

One question, will one 55w cob be enough for veg. of 4 photoP. pl@nts?

 

[Dudeski]

I would probably be ok for a little while but nit all the way they veg. How long are you planning to veg?

 

[L0wbob2017]

I left with one citizen 1212 3500k 90 cri, and i ordered single driver for it, now the thing is i got this old bad ass zalman cpu cooler View attachment 803580 and i wanna put led on it ...
Now I wanna know is it doable..and any suggestion will be highly appreciated..

doable? ofc.

Just for your information, the stock intel CPU cooler is made to cool up to 85W of heat while stying under 60°C. ( active cooling on max setting ) So with your "bad ass zalman" cooler you wont get any heat problems if cooled active. For this you need at least 8V DC because it is a 12V DC fan. The more you get closer to 12V DC the faster the fan will run and the better the active cooling gets. The better the CPU cooler ( only the heatsink ) the slower the fan needs to be to keep it cool. Maybe you come to a point where you dont need any active cooling.

One question, will one 55w cob be enough for veg. of 4 photoP. pl@nts?

Maybe for the first 2 weeks, but after that, the plants will outgrow the coverage. You could increase the distance to the plants but then u would have to make the COB brighter, which leads to more energy cost and heat production. Also only one lightsource for 4 plants maybe wont light out all the leafes. My suggestion would be to do max 1 plant under 1 COB. otherwise you would only put a quarter of the COB watts into the vegging plants which would "only" be 55/4=~14W / plant. So just think about how long could you veg a plant with a 14W COB.

 

[CoviklaFlaire]

@Dudeski I'm planing max 4weeks of veg..To counter.my 12/12 from seed tout..current batch of SBA that I grow were in my bedrooom for 9 days when i was on vacation ,they stretched but were fine,And I had only 7hrs of direct sun light..

@L0wbob2017 I dont get really first part of message,are you saying that I dont need power on that zalman? It can cool it passive?.I have this ac adapter.


Fot second part I understand what you sayin'.. I have spare angelina reflector maybe that could help a little?

 

[Dudeski]

I would use the fan since it will help with the lifetime of the cob. I just dont think one is enough after they get some size to them.

 

[L0wbob2017]

@L0wbob2017 I dont get really first part of message,are you saying that I dont need power on that zalman? It can cool it passive?.I have this ac adapter.
View attachment 806309

Fot second part I understand what you sayin'.. I have spare angelina reflector maybe that could help a little?

The thing i was saying is, that you could do a testrun at 55W for the COB and look how long it takes to get the heatsink warm or hot.( needs to be as long as it would be turned on so 18 hours of testing. Visit the light every 30 minutes and check temp)
If it only gets as warm as your hand without a fan i dont think you will need any fan at all but if it gets hot ( you cant touch it anymore without burning your fingers ) you need a fan.

Also the "rule" is, the cooler a COB, the more light you get out of it with the same wattage and the longer the lifetime of the COB will be.


For the second part i am going to explain it like this:

• COB without Reflector/Lense
  • higher coverange, lower intensity

• COB with Reflector/Lense
  • lower coverage, higher intensity.

• COB with high distance to the plants
  • higher coverage, lower intensity

• COB with low distance to the plants
  • lower coverage, higher intensity

A COB without a reflector/lense mostly has a "beaming angle" of 120-130°.

Calculation of the coverage circle radius:

(Radius of the coverage circle) = (distance to the plants ) x ( tan ( ["beaming angle"/2] ) )

If you install a 90° reflector it means "for every cm/inch of distance from the COB to the plants, the radius of the coverage circle increases by the same amount (cm/inch)."
This means at a distance of for example 50cm the radius of your coverage circle is also 50 cm.

With a beaming angle of 120° and a distance of 50 cm the radius of your coverage circle would be about 86,6 cm

With a beaming angle of 130° and a distance of 50 cm the radius of the coverage circle would be about 107,2 cm.

The thing you are aiming for is the balanced value where you cover everything you need and be as intense as possible to get the most out of the coverage which depends on your growroom-setup and the COB/heatsink/reflector/lense combination.
I found it mostly to be at a distance of 50-70 cm using a 90° reflector.

 

[BigSm0]

Distance of light traveled. Something we will never really understand unless there were spot tests each sq". If the light is undirected by a reflector how many times will it bounce off the tents walls before it hits the canopy. If it's directed will more photons travel the shorter distance. Some people may think this is crazy talk but an inch of travel affects the total ppfd much more than we think. Over a large area doing dozens of spot tests reflectors take the win. For most people and their autos cobs are powerful enough without the reflectors. In a completely dialed in grow I'd say reflectors increase ppfd over the whole canopy.