4 Luminous COB´s LED in 600W tent

Hey and cheers.

I want to discuss a custom LED light with COB´s (chip on board) leds. It should be Luminous chips witch draw 140W from a wall and I will use 4. With Mean Well HLG 54V, 480W power supply i can run the chips with some (10 %) reserve on 2,03 Amps (108W) each. With optics with 93 % efficiency i can get 12 071 lumens from each chip and 48 284 lumens total. That´s 100,5 lm/W. In comparison with 630W cmh Lumatec witch efficiency is 111 lm/W that´s not bad-digital power supply is not so efficient instead i think. It is also pretty cheap light setup. Hardware (LED chips, DC power supply, optics) cost around 370 €-Luminous chips aren´t so expensive as Crees.

So it´s nothing new. And what do you think, are these chips good enough for 120x120 box?

I think this video is informative and i used it in my project.


In my experience, the LED strips out perform COBs and are a lot cheaper to DIY. Check out what is being done with these strips.


I already bought the aluminium heatsink, 55 cm long, 3 pcs. First i thought i will grow in IKEA micro cabinet but it was too nice and the heatsink also. I will try maybe only 280 watts first but it’s not efficient setup then.


COBs it is then! They work, better penetration, worse spread IME. I was still using my Cree cobs until a few weeks ago.


Exactly man, i researched more and i think best solution is now try 2 140W LEDs as i mentioned in last post with 320W driver. This is reasonable choice (HLG-320H-C2800A) and far more effective, it can pull 32 000 lumens. With some additional lighting it is enough for 1 sq. metre /400W tent. For 600W tent i will try Luminous horticulture LED in this setup.

For now i don´t know witch color temperature choose, 3000K or 3500K or mix (3000K and 4000K/5000K). This confuses me because i can´t find spectral diagrams.

If you are going to use it solely for flower, I would stick with the 3000K, otherwise I would go 3500K for bot veg and flower.


I ordered 2 3500K 140W chips, 3000K was not available at the monent :/.

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3500K is still a good spectrum for flower. :+1::seedling:

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COB’s arrived. Driver on the way. It is HLG 150W. I will grow in small cab first and can use it to run only 1 chip on full load later. Square optics i think should work well with these:


COB´s are very hot (actually the heatsink), should I use the fan?

I´am running them on 700 mA probably.


I think the only right way is to get some scientific instrument like PAR meter. But plants do always tell too.

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I do a small improvement with the pair of 12V fans on a single power source. Chillish temperatures of 36 d. celsius is better than 48 d. c. before.

I grow some pepper plants along with weed.


So far good. This light cost me 180 euro, but i have 2 aluminium heatsink more so i can upgrade to 6 chips (450W) in larger tent and it will cost not even 3 times more (1 euro/watt is possible). Do you have something to comparison, please?

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I am updating on the Sundays. Added two more fans on the same power source. It runs on 3V.


Bump, update.

150W of LEDs light doing its job. Pics tell for itself. Tent is 1sq meter. I can say 3500K has much blue in it, plants are bushy and compact. 3000K would be better for flower but it is not available at the mouser.com, I need to add some red/orange in the spectrum. BIN of COBs is 80 CRI.

Next job is to light up the corners with 3W LEDs


Love these SJ. I’ll do a thread soon too. This photo need some color balance, bwe.


Have some pH issues. I need to buy pH 4.0 and 7.00 to calibrate new pH meter. PH is most definetally too high.

SJ - Sannies jack, F7 or so.
20 days veg.

I hope they won’t need repot next 14 days. Got feed with 8-8-8 universal fertilizer. Epsom salt should be also good.

Aerial view

Zoom in


I learned a ton from testing of these COBs.

  1. provide optics for COBs - to come
  2. provide enough space for each plant
  3. provide air flow for both COBs and plants
  4. provide oxygen (CO2 actually) with vent
  5. feed less, water more (less but more often)

These 5 steps were necessary with strong COB light for good results with vegetables.

The results from vegetable garden


Sweet peppers


Nice setup you have there! The plants obviously love it! :heart_eyes:
Those heat-sinks are massive & they really go with the hangers, very functional with a steampunk like vibe. :+1:
If you have access to a IR thermometer it would be interesting to see the temperature gradient on the heat-sink but you would probably have to measure on the fin side.

If you ever need to lower your tent ambient temperature a simple fix would be relocate the driver to the exterior of the tent. That will reduce about 20~25 Watts of heat.

My only suggestion (a minor one) is to tidy up the wiring a little. It might avoid a potential accident down-the-road.