Another lighting question

[JDU]

So what is the dif between LED & COB led?

[Mrblu]

Simple answer efficiency. Spectrum to some degree. Im no expert though. I believe generally accepted cobs are 'better'

[DingusKhan]

It's a design type where normal LEDs are the tiny little bulbs that have a huge array of like 30x50 (I haven't counted them) of little bulbs, where a COB is one high output LED bulb on a little circuit board. COBs can emot full spectrum light where normal LEDs each emit one wavelength of light.

[Obi-Wan]

Short answer is that they are all LED lights.

A typical Blurple or traditional LED light fixture will have its diodes spread around the fixtures board. These lights use 3 watt, 5 watt, or 10 watt diodes and are generally listed in equivalent wattages that assume the maximum capacity of the diode used but they are only being driven at 20-50% of that capacity. So they call an LED that uses 100-10 watt diodes driven at 20% a 1000 watt LED but it only pulls 200 watts. While they sometimes use fewer watts than traditional lights, they are actually less effective at turning those watts into light. This style of LED is roughly 25% effective so you get about 50 watts of light and the other 150 watts go to heat and the fans that blow that heat away from the fixture. You would need 3 of these fixtures to produce the same usable light as a 400 watt hps.

A COB or Chip on Board fixture uses a chip made with smaller tightly packed diodes. The chips are generally 1”x1” squares or 2” circles. The better COB fixtures won’t have fans for cooling. If they use a quality chip, matched with the proper driver/heatsink combination and driven at the proper wattage they shouldn’t need any active cooling. Quality COB fixtures are about 60-70% effective at turning energy into light. 220 watts of quality COB’s can produce the same light output as a 400 watt hps.

Quantum Boards use chips such as the Samsung LM301B, that are similar to COB’s but much smaller and they are spaced over a board or strip. Quantum boards can be driven to reach efficacy rates of 90+% with most typical results in the 80-90% range. 200 watts of Quantum board LED will produce about 20% more usable light than a 400 watt hps.

[Gingerbeard]

Damnit, Obi-Wan. I was going to say that! I actually know this one. Except for the Quantum Board deal. I have got to figure out how to do that in my little tent.

[Toker1]

What kind of HPS bulb are you comparing these specs to?

[Obi-Wan]

Hortilux bulbs are 35-40% effective at converting energy into light.

[YYCannabis]

Strips are the answer.


One of the limitations of COBS is that they act as a spotlight. What’s directly under it gets a sh!t-ton of light. The periphery of the light footprint can get very weak very quickly. Good quality lens can help distribute the light better.

Strips come in all the K spectrums for vegging and flowering, plus lengths of 1’/2’/4’.
COBS are so 2018. 😎

[JDU]

I went on Amazon to buy another 3 sets of led strips but they have gone up $25 since I bought my set. At $50 I loved them. $75 is pretty high for 360W. So I went looking for a ne for light & the more I read the more confused I get lol. I might have to lay off the pipe long enough for the fog to clear. ☹

[JDU]

All that wiring I'm sure we arent talking about the same strips. Did you make them? Where do I get them? How much does each cost & how many watts each?

[YYCannabis]

JDU If you want to know more about my lights you can start here https://forum.growweedeasy.com/forum...ed-light-build
I didn’t do a detailed build log here in GWE but there is a link to my detailed build log on the LEDgardner website.
As for cost of the strips, the ones I used are more pricey than some of the others available. You can grow some amazing weed with just these strips on DigiKey part # BXEB-L0590U-40E1500-C-C3
This is a 4000k strip; 22” length, 200lumen/w running at a mere 700mA. Ten of them is only $86 CAD. You could get 20 of them for about as much money as I spent on 3 of my strips.

[gbauto]

Obi-Wan pretty much nailed it.
Old school monochromatic diodes used in 'blurple' are the least efficient and at best can match a single ended hps fixture.
COB's were the next step up on the tech lpadder. Using a white light spectrum, they offered high power density and much better efficacy compared to the mono's.
Surface Mount Diodes(SMD) like the lm301b are the current top tier diodes and compared to monos offer almost double the output of light for each watt of power used.
QB's and similar design light engines that use SMD's offer better uniformity compared to point sources like a cob.
I use both cobs and qb/light strips in my grow.

[Toker1]

Blue-Purple lights are way below HPS efficiency my friend. Even a single ended hortilux HPS bulb is close to the efficiency of a quantum board with a quality driver and chips.
Cheap bulb using MH would be more like it in terms of efficiency.

[YYCannabis]

JDU Getting started is the worst part. I’ve been a DIYr my whole life. If there is anything that I’ve learned over the years is “If you can afford to do right, do it right”. If you believe this is a hobby that you want to not just “do” but get good results at “doing” it, then it’s always worth it to start right. I know that not everybody can afford to start out with $2000 in costs before you even see a bud grow a hair. 🤣
Three things to keep in mind with lights:
- lights are food
- lights are yield
- lights cost $$ (Purchasing and operating)
Ask yourself what you want for results and how much money are you able to invest to get those results. Each is directly proportional to the other.

JohnEmad COBS are certainly a great way to grow. LED emitters on strips, or packed into COBs, will do their job just fine. I decided to use strips because I can keep them close to the canopy, and they run cooler (temp and amps). You will see in my pics that the strips are about 8-10” away from the plants and I’m running them at 600mA. I could put those strips up at the top of the tent, and crank up to 1200mA and get the same results. Only difference would be heat waste, and shortened lifespan of the emitters.
If you go chasing the “latest models”..you will never actually buy anything because the newest technology is always just a few weeks away..then the next one...then the next one...😉

[Toker1]

Double ended HPS I have seen at 160 lumens per watt. Single ended HPS I have seen at 155 lumens per watt. A new quantum board is around 180 lumens per watt.
Those blue-purple LED’s are not even close to being as efficient as a decent HPS bulb is. Keep in mind, most LED advertisers that say otherwise are comparing cheap Chinese made HPS bulbs to their LEDs. All the growers I know use yield lab, digilux, sun pulse, sun master, ushio, or hortilux. We wouldn’t trust our grows with a $10 HPS bulb used in these case studies. When you compare the lumens per watt on a decent bulb (the ones most growers use), the facts speak for themself

[Obi-Wan]

HLG’s QB 132 is capable of 204 lumens/watt when driven at 700 mA and 23 watts. A fixture that utilizes 8 boards and 2 drivers wired in series with 4 boards per driver would easily cover a 4x4 producing 204 lumens/watt over the entire canopy at just 184 watts total draw. The cost to build this fixture would be around $500 which is cheap when compared to the fixtures that HLG is selling for the same space. Their QB 288 boards get all the attention because they use them for their fixtures but the smaller QB 120 & 132 are better boards because of their versatility.

[Toker1]

I know there are LED lights that are capable of over 200 LPW. But let’s be realistic, most people using quantum boards are using the 180 LPW models.
Yes, there are new single ended HPS bulbs capable of 190 LPW... but I only know 1 grower that uses them.
The average every day grower you meet are not hitting those benchmarks with the gear they are sporting.

[JDU]

Well I certainly can't spend that kind of $ anytime soon. The wife would cut me off if she knew how much I've already spent. But this harvest proved that I can't run T5 & LED together. I need everything at the same height so I guess I'm looking for a COB fixture or a quantum board. Any suggestions as far as brands to watch (or watch out) for? I'm using 4x4 of a 4x6x7 tent.

[CatMomma]

I’m interested in this too since I’m thinking about getting a small tent with a Mars Hydro ts 600 watt... I’m still new at this and it’s overwhelming at times...

[Gingerbeard]

YYCannabis I took a look at some of your links and don't see distances. Like, from top of light to top of tent and from light to canopy.

[YYCannabis]

I run mine at approx 8-10” from canopy. This gives me approx 50k lux. I’m currently running them on an angle to maximize photon emission. I’ll post a pic below

[YYCannabis]

The plant on the left side has 12 strips running 30watts each...360 watts getting into the heart of the lady.

[Gingerbeard]

It's beautiful, dudebroman. The plants are cool enough but your lights are beautiful.
I need to start piecing something like this together for my 2x3. Maybe run the length of the tent and do six two footers? Your canopy distance beats the 600 watt LED I'm using on limited loan. That one's 22" minimum during flowering. Maybe start with two to augment the 350 I usually use? That's only a 16" canopy.
Crap! That could add more than 6" to my plant height when I get a full setup! Crap!
Gawd love you, dudebroman.

[YYCannabis]

I should also mention that the plant on the right has only 8 strips pointed at her. She’s a couple inches smaller, and less leaf-dense than the other plant. I also rotate them 90degrees everyday to keep balance of light and shadows across the little buds hiding in the middle. The main kolas don’t seem to give a f*%k which way they get exposed to the strips because their like “f*%k it man, we be happy 6 ways from Sunday with this light” 😎🤣

[YYCannabis]

Plant surface temp is 25C (77F) at the spots closest to the strips 😎. I run two oscillating fans that are primarily to cool the heatsinks, but they also give me circulation for the ladies.
I have plans on a second generation modification to my lights. Early spring.

[JDU]

Oh wow. I couldn't get my tent under 84F this last grow. Between that & the pics of your girls I better look into this!!! Would 10 of those less expe.sive ones cover 4x4?

[YYCannabis]

Might need a few more. With these strips, one benefit of adding more strips, is you can run them at lower power per strip — lower heat emission — closer to canopy. And at $10/strip...the decision is pretty easy. Remember, lights are food 👍 and dealing with excess heat from other high temp lights is costly.
Have a look at my build journal. Start reading over on LEDgardener some of the info on led lights. There are a multitude of build guides for different size of spaces. Lots of very smart people in there too.

[YYCannabis]

https://ledgardener.com/forum/viewtopic.php?t=5083

Build journal.