Opinions and advices for my new cheap idea. LUXEON COB GEN 4 (2.5 X 2.5)

[violenzo]

Hi guys, so the eb strips are out of stock. I was wandering on digikey and i found this:

https://www.digikey.it/product-detail/i ... ND/8445964 3000k
https://www.digikey.it/product-detail/i ... ND/8445969 4000k

I don't know if they are valid chips, but i wrote down an idea for a 2,5 x 2,5 grow space, here it is:

2 x 4000k
6 x 3000k Total: 63 €
Edit:
1 x ELG-200-C700A (dimmable): 39 €

So i run the cobs @700ma, for a total wattage approx 195w - 30.000 lm approx (just for comparison)

NOW, QUESTIONS TIME!:
Can this chips grow something?

Which heat sink i need? (i would prefer something like this http://www.heatsinkusa.com/2-079-low-stock/, i need to stay cheap, and i want to attach chips in this way: HEATSINK 1 ( 3 - 3000K) , HEATSINK 2 (2 4000K), HEATSINK 3 ( 3 3000K)

I calculated a value of 2,2 c/w..but i'm not absolutelu sure of this..here is the datasheet

https://www.lumileds.com/uploads/600/DS162-pdf

search for F1500

So, if anybody can help..which cheap (or not cheap) heatsinks i have to buy?

was going to buy a clu 048 1212 kit 200w..but i think this setup is better..and with some cheap heatsink a way less expensive.

Now, just gimme some hints and opinions please..thanks in advance. Enzo.

[ShowMe]

See what second-hand ebay cpu heatsinks go for in your area. I've been able to get them for a few dollars each, and they get rid of 50-100w of heat each. If they are cheap for you, attach your COB holders to an aluminum bar from a metal supply place, and use thermal adhesive to attach the heatsinks to the other side of the bar.

That said, even alibaba "quantum boards" will probably outperform the chips you linked. 151 lm/w is 2016 efficiency.

[alreaaaa]

I Don’t Know about those luxeon but you could always go with vero18 which we « know » can grow and they are about the same price even cheaper I think

I will check which heatsink would be good for you tomorrow . USA or Europe ? So I know where to look at but if you run your chips @ 850ma you could even get really small passive unit but it would mean you making a frame for your heatsinks

[violenzo]

See what second-hand ebay cpu heatsinks go for in your area. I've been able to get them for a few dollars each, and they get rid of 50-100w of heat each. If they are cheap for you, attach your COB holders to an aluminum bar from a metal supply place, and use thermal adhesive to attach the heatsinks to the other side of the bar.

That said, even alibaba "quantum boards" will probably outperform the chips you linked. 151 lm/w is 2016 efficiency.

thanks..i was thinking about a similar heatsinks style..

Is the aluminum bar empty inside? like those used in construction?

alibaba don't grow..machete don't text..

but..sorry i don't understand the 2016 thing..the famous cree LED COB CXB3590 3500K WHT SMD isn,t 146 lm/w?

aside the quantum board(i can't find the bridgelux strips)..which is a chip with a good l/m coefficient?

[violenzo]

I Don’t Know about those luxeon but you could always go with vero18 which we « know » can grow and they are about the same price even cheaper I think

I will check which heatsink would be good for you tomorrow . USA or Europe ? So I know where to look at but if you run your chips @ 850ma you could even get really small passive unit but it would mean you making a frame for your heatsinks

thanks!europe... very gentle..today i'll take a look at vero 18..i think that even if i spend the hallf of a cree configuration..i can have a good result..unfortunately i can't test the chip..i don't know an electrician otherwise I would have bought one of them to test umol ppf ppfd etc etc..i googled the chip but nothing..a cheap chip however..maybe it works. no problem for the frames..i was a drywall carpenter..i saw something good from mechatronichs..5 dollars each..but i would 'prefer a bar..i'll see..

have a nice weekend!

[violenzo]

Found this https://www.ebay.it/itm/Aluminum-Alloy- ... SwMlRakpA0

maybe if i run them @700ma in series with this https://www.digikey.it/products/it?keyw ... -200-C700A
it would be enough..30.000 lm..

[alreaaaa]

Hey there

@violenzo

So if you really want to run em at 700mA you can take this https://www.elpro.org/gb/led-heat-sinks ... 630-b.html and you can easily put the vero18s on this with 2 self taping screws m3

The driver is also available there if you need https://www.elpro.org/gb/-200-w-ip67-co ... c700b.html

Elpro is european store but prices are without VAT

I don't know where to find vero18s in Europe yet, I plan on using them and selling them on my site later but I don't see it anywhere in Europe for now unfortunately so Digikey would be the solution ..

Or you can always get some heatsinks bar from TME like https://www.tme.eu/fr/details/rad-a5724 ... stonecold/ but I wouldn't be so confident as to be a serious passiv unit so I would recommend using a fan over the top of this kind of bar just to make sure the temp doesn't go out of control

At the bottom of this post from this very site, you can see how vero18 work with Moruga Pepper
http://ledgardener.com/build-led-grow-light/

[TiJay]

Or you can always get some heatsinks bar from TME like https://www.tme.eu/fr/details/rad-a5724 ... stonecold/ but I wouldn't be so confident as to be a serious passiv unit so I would recommend using a fan over the top of this kind of bar just to make sure the temp doesn't go out of control

Thanks for the link, I was looking for a bar like one of those for a new project i'm working on: A bar with some low power Vero 10 4000k-5000k for seedlings and cuttings.

[alreaaaa]

@Tijay You're welcome , always happy to help when I can =)

[axef]

Hello folks

I've recently built a modular Lumileds LUXEON COB light with 6 L2C2-1208 COBs, to cool down the cobs I used three big heatsinks from fischerelektronik the SK89 with a passive thermal resistance of 1K/W, and placed 2 cobs for each heatsink.
I rum my 1208 cobs at 1050mA, which means 37.8 W each one, so the total amount of heat dissipated from each heatsink is in the worst case 37.8W * 2 = 75.6 W, and to be sure to keep the cobs junction below 125C I've also placed a 80mm FAN to each heatsink. The system manage heat pretty well.

Another interesting question is PPF.
In the datasheet you can find the spectral power distribution over the wavelenght of the light emitted, roughly speaking, the PAR radiation is the total amount of power between 380nm and 800nm.
I extrapoleted datasheet spectral distribution chart and elaborated to convert it in numerical data.
With numerical data, it is possible to integrate power over wavelenght in order to calculate PPF.

Below PPF for some COBs @ 1000mA, and assuming a LED efficiency of 30% (the capacity to transform electrical power in light):

L2C2_70_5700K
ppf: 48.03453837990068 umol/s

L2C2_80_2700K
ppf: 49.01280628712339 umol/s

CXB3070_80_3000K
ppf: 47.878880284205316 umol/s

CXB3070_90_3000K
ppf: 45.778220550503654 umol/s

Please consider that I've NOT measured the real ppf, and values reported are only results from theoretical calculations. Could anyone validate data for CXB3070? Is calculation close to the real output?
I'm not sure that 1208 COBs can provide enough power and the right light spectrum for growing plants.

Regards
Alex