Back after a break. COB or QB advice

Due to a change in circumstances my height went from 12 feet to about 6/7. I ran COBS a few years ago but life happened and had to pull it down just before I flipped. The whole thing left a sour taste in my mouth so sold all the fixtures I built and actually made a decent profit from selling the fixtures. Then I had the place with 12ft height so just went back to using gavita pro since I had them at hand and a solid tried and tested method.

Now height and heat are going to be a problem so going to try LED again.

I was going to build the cxb3590 200w 4ft fixtures from the growmau5 videos I first followed. I still have enough parts left over to build one 4 cob 200w fixture and have 3 extra HLG-185H-C1400B. So that would be a nice saving right off the bat if I go down that route.

Scanning through this section there seems to be very little on the cobs though compared to what it used to be.

I'd be looking to do scrog with long veg to keep the plant count down so penetration isn't as important as when growing trees.

I know I'll have to do my own research but been really out of touch with everything LED related for the past couple of years, I remember @SupraSPL content was very informative at the time. Anyone can point me in who is leading the way with QBs or strips? Helpful guides. Even just a straight start to finish build would suit me, either QB or strips. I had a tough time the first time round trying to wrap my head around a lot of the electronics/physics jargon, I'm happy to ignorantly follow a tried and tested method haha.

Ideally I'd like to keep costs down so happy to build my own. I originally ordered from Kingbrite, I was hoping costs would have came down a good bit with new technology but perhaps with the popularity of deadmau5 videos and this forum has kept the prices about the same as they were in 2015? I'm not too fussed about squeezing the tiniest amount of efficiency if it's going to ramp up the initial investment by 100s of $. I'm international and can't see international shipping options on HLG, but again if I can save a chunk of cash building my own that would suit my circumstances.

If I choose QB or strip lights can I utilise the HLG-185H-C1400B drivers? Or is that apples and oranges?

My space is about 10ft x 5ft and 6-7ft height (sloping roof). So 2500w is max from what I'm reading, how would I achieve this. What sort of colour mix? Do you still use 3500k start to finish. The QB seem to be more of a blend?

The boards look like I could squeeze an inch or 2 in height if I have the drivers outside the grow space which is appealing. Even toying with the idea of vertical as I then have closer to 10ft to play with but probably keep it simple first time round.

I like drain to waste with JR peters 3-2-1 in rockwool. I sometimes run into deficiencies, etc on some strains. I remember people used to run into problems with deficiencies with LED, magnesium comes to mind, has this been solved? Are there certain nutrient lines that run better with LED? I'd hate to run into all kinds of problems if both the 3-2-1 and the lights caused their own issues.

There seems to be a bit more consensus now that using IR and UV are beneficial from some of the threads I've been reading. Is there a good post on this, with more weight on the how rather than the why. This was another brain melt discussion I didn't fully understand then but would like to try implementing it if the parts are more readily available than they used to be.

Are there any decent compilation lists on threads or videos, or gurus on the subject, wish more was in the stickies!

Can something like this be DIY'd, would there be a notable saving?

From the research and comparison I have done there is basically one supplier worth using for each component and for the price of shipping, etc you come out about equal to the cheapest branded LEDs at least in my country. Not sure about the majority of bar LED but it seems Mars and SpiderFarmer PCBs are produced in the same factory by Samsung so if you go straight to the source who knows what costs you can cut.

st0ric said:

From the research and comparison I have done there is basically one supplier worth using for each component and for the price of shipping, etc you come out about equal to the cheapest branded LEDs at least in my country. Not sure about the majority of bar LED but it seems Mars and SpiderFarmer PCBs are produced in the same factory by Samsung so if you go straight to the source who knows what costs you can cut.

Click to expand...

After some more scouring and reading a bit about umol/j seems hlg is the way to go. The mars and the spiderfarmer fixtures cost more or less the same and not 100% on whether they're trustworthy enough on their numbers or if the guarantee holds up should something malfunction. Remember there being a lot of hate for mars at least.

What I can't work out, does increase in umol/j as a percentage equate to that increase in yield. So say a light with 2 umol/j vs a light with 1.5 umol/j, does the second one equate to a 25% increase in yield if all other variables remained the same?

CouchGouch said:

HLG 700 RSPEC FR - Horticulture Lighting Group - UK & EUROPE

hlg-uk-europe.com

Can something like this be DIY'd, would there be a notable saving?

Click to expand...

Yep I diy'd my light rig using v3 quantum panels, heatsinks and some cheap cobs from Ali express.

Think you'll have to look at cobs for those drivers you have. They have too high an output voltage and not enough amps for the quantums. Pretty sure they need 48-56v dc 2100+ mA drive current

DIY strip builds are great for height-restricted scrogs. You can spread them out over the entire area and hang them very close to the canopy.

Two of the LEDGardener 5x5 Bridgelux EB2 designs would fit your area and budget. One thing I like about strip builds is in a lot of cases you can forgo heatsinks by adding more strips.

THIS THREAD is good for finding deals on drivers and strips at arrow.com. If you aren't too bothered with efficiency there are some really cheap strips and cobs at Arrow.

CouchGouch said:

What I can't work out, does increase in umol/j as a percentage equate to that increase in yield. So say a light with 2 umol/j vs a light with 1.5 umol/j, does the second one equate to a 25% increase in yield if all other variables remained the same?

Click to expand...

Umol/j is basically a measurement of how much plant-usable light you are getting per unit of electricity. Say you needed 1500 PPF over an area, and you used a light that would require 650W to produce that, you divide the PPF by the Watts to get 2.3 umol/j. If you used another light that only needed 550W to get 1500PPF you would get almost 2.8 umol/j.
Umol/j is a measure of system efficiency, like a miles-per-gallon rating, not a direct measure of total light or growing capability.

So if you had two 4x4 tents, one with a light with a 2.0 umol/j rating and the other with a 1.5 umol/j rating, and they were both providing 1500 PPF each, the only differences would be one uses more electricity->costs more to run than the other, and would run slightly warmer.
If both lights were limited to using say 300W of power each, then the 2.0 umol/j would be able to provide more light over that same area and would therefore yield more.

MedicinalMyA$$ said:

DIY strip builds are great for height-restricted scrogs. You can spread them out over the entire area and hang them very close to the canopy.

Two of the LEDGardener 5x5 Bridgelux EB2 designs would fit your area and budget. One thing I like about strip builds is in a lot of cases you can forgo heatsinks by adding more strips.

THIS THREAD is good for finding deals on drivers and strips at arrow.com. If you aren't too bothered with efficiency there are some really cheap strips and cobs at Arrow.




Umol/j is basically a measurement of how much plant-usable light you are getting per unit of electricity. Say you needed 1500 PPF over an area, and you used a light that would require 650W to produce that, you divide the PPF by the Watts to get 2.3 umol/j. If you used another light that only needed 550W to get 1500PPF you would get almost 2.8 umol/j.
Umol/j is a measure of system efficiency, like a miles-per-gallon rating, not a direct measure of total light or growing capability.

So if you had two 4x4 tents, one with a light with a 2.0 umol/j rating and the other with a 1.5 umol/j rating, and they were both providing 1500 PPF each, the only differences would be one uses more electricity->costs more to run than the other, and would run slightly warmer.
If both lights were limited to using say 300W of power each, then the 2.0 umol/j would be able to provide more light over that same area and would therefore yield more.

Click to expand...

Thanks for that info, had a look over the custom build link you gave over the holidays which was great cheers. Also been a lot of back and forward, thinking I get it then realise I don't haha, guess catching up on 5 years progress over a few days was a big ask!

I read through cobshopgrow's thread and thought I'd try replicate that, but realised I don't know enough about voltage/current, etc to do something that custom safely. I did like how he added some far red and uv though.

I then read through, among others, BKR's grow journal who uses something simlar to Meiju 650W grow lights. He is hitting close to 2g or well over a gram anyway with this.

I then saw King Brite lm301h board which is 230 watts less but half the price. It’s missing the far red and uv but from reading cobshopgrow’s diary I think I can add those fairly easily and cheaply. Both lights use the same Samsung LM301H diodes, I’m not 100% sure how many diodes each has in comparison or how hard they’re driven though.

The 480 boards have about 2000 diodes (from counting on a crappy jpeg) ran on a MW 480H-48B. The LED quantity on the 650w one is 2544 on an inventronics-EUD-600S12ADT. So I imagine they’re being ran similarly hard?

I usually hit 1gpw or more with the gravitas and a fresh bulb. So if I could hit 1.2-1.5 in my space, well there’s only so much flower you can grow in a 4x8 before you start running into problems. So wondering if I could get away with 960?

Are there any concerns over the legitimacy of their diodes actually being Samsung, will they all be Samsung or can they claim that and only use 10% and the rest something else? Kingbrite have been in the game for years now, I’d imagine they would want to protect their image? Will they have diode failures or current issues or whatever compared to a HLG say? Any reason why they wouldn’t last the 50,000 hours claimed again compared to a HLG?

I watched a growmau5 interview shilling HLG lights and one of the biggest selling points in comparison to Chinese lights was the CE rating. Since Kingbrite are using from what I can tell legit components and drivers. I can’t see much difference from my albeit amateur eye between them other than the HLG are 3x the price.

Lots to think about.

Anyway Happy New Year!

HLG and other higher end manufacturers use 'top bin' diodes from Samsung or whoever. Samsung the most popular but not necessarily not the best.
Also, LM301h's are not all the same. Due to manufacturing variance, some are better than others. All are tested and put in a classification (bin).

Generally, the better the binning the more they'll cost.

CouchGouch said:

I then read through, among others, BKR's grow journal who uses something simlar to Meiju 650W grow lights. He is hitting close to 2g or well over a gram anyway with this.

I then saw King Brite lm301h board which is 230 watts less but half the price. It’s missing the far red and uv but from reading cobshopgrow’s diary I think I can add those fairly easily and cheaply. Both lights use the same Samsung LM301H diodes, I’m not 100% sure how many diodes each has in comparison or how hard they’re driven though.

Click to expand...

I have zero experience with AliBaba/Express lights, THIS THREAD is all about it though.

CouchGouch said:

I usually hit 1gpw or more with the gravitas and a fresh bulb. So if I could hit 1.2-1.5 in my space, well there’s only so much flower you can grow in a 4x8 before you start running into problems. So wondering if I could get away with 960?

Click to expand...

30-40 Watts per square foot of canopy is a good amount when using modern LED's although I prefer to target PPF per square foot averages.
I have had good results using 600W per 4x4 when 'normal' growing, and 450-500W when scrogging and using strips a lot closer to canopy.
A big benefit I have found from using strips when scrogging, is the light can be almost sitting on the canopy but still provide full coverage, whereas boards require a bit more headroom to achieve the same spread. With the strips hung lower, I can dim them but still get my required PPF.

CouchGouch said:

Are there any concerns over the legitimacy of their diodes actually being Samsung, will they all be Samsung or can they claim that and only use 10% and the rest something else? Kingbrite have been in the game for years now, I’d imagine they would want to protect their image? Will they have diode failures or current issues or whatever compared to a HLG say? Any reason why they wouldn’t last the 50,000 hours claimed again compared to a HLG?

Click to expand...

The 50,000 hour lifetime sellers advertise are based on the lifetime ratings given by the LED diode manufacturers themselves, something like e.g. 'L80 50K' which means after 50k hours of use they will still produce 80% of their original output, depending how hard they are driven.

CouchGouch said:

I watched a growmau5 interview shilling HLG lights and one of the biggest selling points in comparison to Chinese lights was the CE rating. Since Kingbrite are using from what I can tell legit components and drivers. I can’t see much difference from my albeit amateur eye between them other than the HLG are 3x the price.

Click to expand...

The CE marking is a European 'Declaration of Comformity' basically a symbol saying you as the manufacturer have made everything to certain safety requirements/other standards etc, and they are fully liable. In China I believe it means just another squiggle to include somewhere on the documentation. Mean Well drivers have serial numbers you can check to make sure they are legit, I think the linked thread above has some posts in it where diodes are checked for legitimacy.
I have used HLG products for probably 5 years now, and I can only rate their customer service as excellent. Any issues were quickly resolved. Everything I have ever bought from them works as it should, and is still working.

So paying for HLG, you are paying for guarantees that you are getting what you pay for, it won't kill you, and actual customer service. Plus, HLG are pretty much the progenitors of Quantum Board style horticultural lighting, I think they invented and trademarked the term 'Quantum Board'.

I see plenty of threads where people are killing it using China lights tho.

And Happy New Year!