growopz

They're using the 'H' type. The 'H' driver is 91% - (you are presumably using the 'L' one then.) Yeah the drivers will let you push them way over max, especially the CV ones, but it's obviously not recommended, as the temps go to max.

Just my 2c: Notice that the 220W light only has 416 LM301B diodes, and that the XLG-240 driver is only 91% efficient, and that aluminium plate is not a particularly good heatsink. According to the specs, it's only 200W at 230VAC, though I presume that's a misprint. XLG-240 should handle 220W.

Hi @DamDave, LEDs get better efficiencies (lm/W) at lower currents and cooler temperatures. We have watt-meters in stock. It's possible to estimate with a very accurate multimeter, but a watt meter is simpler. Pretty useful in general too, to see your electricity use. You can grow seedlings with 15W. There's no need to blast them with 75W. But if you do decrease voltage, you need to be careful changing the voltage back up, as IV curves (voltage vs current) is an exponential curve, and you will damage the LEDs if they run for long, above their rated maxes.

@Daan PosthumusThe QB-130 & 120W Luminus CXM-32 will both be R2500, and more appropriate for 80x80. People use up to 240W in 80x80, so it's all relative to expectations. The tent size just sets a max on the amount of light you can put in there before you get diminishing returns. The max is around 240W for 80x80. So an experienced grower can yield 75g+ with the QB-75. Yield correlates best to light wattage, with the QB board's efficiency important, but only accounting for max 18% difference in yield, at the same wattage. (That's calculated from the efficiency difference between running LEDs at nominal efficiency (65mA per LED) vs max power (200mA per LED). )

Hi, Thanks for the tag, @SkunkPharm Finishing up backlog on small lights and receiving the rest of our heatsink order from January, next week finally, so am expecting to have the grow bar range back up soon, and new high efficiency veg range after that. If in big rush for a small light, Looking at the links above, the one website is just random chinese crap. I would advise against that. The modugrow one looks pretty sweet. I can't tell what the difference is between their 90W lights, but the specs are solid. It's 1/3 of a standard 240W Quantum board light, for R2k. The QB-75 will be back next week, and is going to be R1250 going forward. Compared to the 90W Modugrow, the QB-75 is about 10% less efficient, and 15W less, but also costs R800 less. So it's a slightly different value proposition.

Def the driver. It's pretty easy to fix, but requires either a 600mA or 900mA driver replacement, and you won't know what until you open it up.

Migro did a video on them 1.49 PPFD/W Convenient, but not great efficiency. Looks like a bit of a death trap, too. Compared to buying a 2 PPFD/W light for twice the price, you'll save money up until you've used about 600kWh. So you'll get 500 days worth of 12hrs/day light (or 333 days of 18 hrs/day), until it becomes more expensive overall with electricity, than a 2.0 PPFD/W light. (Assuming price of electricity doesn't rise)

There's a spectrum, *cough*, of compromise. AC COBs are on the far cheap-up-front end of that spectrum. AC COBs are just super inefficient and dangerous (1) the IC driver tech is not very good yet, and (2) those cheap COBs use inefficient blue LEDs hitting inefficient red phosphors, instead of just using red LEDs. (3) They can kill you or give you nerve damage, if you have an accident with exposed AC, and no grounding wire. @Trailblazer420 - Please put some hot glue or silicone over the AC pads. Do it for the children

At 750W, (500w flower 12hrs/day, 250w veg 18hrs/day?) you'll end up spending a lot more in the long run with cheapies. 12*0.5 = 6 kWh 18*0.25 = 4.5 kWh 10.5 units * 30 days = 315 units/month That'll put you in a residential bracket, so at minimum, R1.90/unit. Or about R600/month. Migro measured the efficacy of two ebay AC COBs to be 0.29 ppfd/watt for the purple, and 0.65 ppfd/watt for the warm white. So let's say 0.45 as an average. So 750w of 0.45 ppfd/watt AC COBs are equivalent to 168W of a decent 2 ppfd/watt light. At the same 2/3 division of 12/18 hours/day, you'd spend 12*0.111=1.34 units 18*0.056=1 unit 2.34 units * 30 days = 70.2 units Or, R133.38/ month on electricity. So if the efficient, expensive light costs R3500, for example, and the DIY AC COBs cost R350, for example, 3500+133x=350+600x x= 6.74 months So that's how long you can use it (assuming they last that long) until it starts costing R467/month more to run the DIY setup. Anyway that's my party pooping 2c.

I forget what shipping I used, sorry. Probably Fedex though, because it was fast. One week.

"Citizen 1212 is probably the weakest brand-name COB on the market. " Citizen's not a bad brand name. Citizen invented the COB. I said the 1212 COB is not great, as far as COBs go. Why Blues? I get a lot of aquarium customers. The COBs will be good for making cheap marine tank lights. I'll probably also make a once-off grow light prototype with the blues and ambers, just for the hell of it.

@PsyCLown It's one of our old prototypes

They have a sale on, at the moment. I picked up a bunch of Vero29s for $15 and some Citizen 1212 Royal Blues/Ambers for $12. Shipping was pretty fast. They're likely trying to get rid of their Citizen 1212 and Vero29 stock. Citizen 1212 is probably the weakest brand-name COB on the market. Vero29 is a solid COB though. Better than Cree CXB3590 in all my testing. But Bridgelux has improved efficiency of their latest gen 7 COBs by 6%, so maybe they're trying to get rid of the older ones.

Yeah, the info is a bit outdated. Black Dog LED released the first "3W" designs in 2010. Then moved on to "5W" LEDs around 2015. These days, QBs and COBs are made with 0.5W and 1W chips typically. Horticultural LEDs from Phillips, Cree, Osram, etc. are typically 3V and run at 350mA, for about 1W output., with 58%+ radiant efficiency. You can still get decent PAR with 3W/5W chips, but it's mostly because of the lenses. Pretty much only the Chinese still manufacture the 700mA and 900mA "3W" and "5W" chips, using Epiled/Epistar/Bridgelux dies, which max out around 25-30% radiant efficiency.

What a bunch of BS. "Photopic luminous efficacy of radiation has a maximum possible value of 683 lm/W, for the case of monochromatic light at a wavelength of approximately 555 nm (green)" https://en.m.wikipedia.org/wiki/Luminous_efficacy He's using the Cree Product Characterization Tool for his "800lm/W" without understanding that it's a spreadsheet tool, and not a specification. --- Samsung LM-80 test data has their chips maintaining 70% brightness for at least 93,000 hours (~10 years continuous) --- 186lm/W is a meaningless measurement for a red led. Cree XPE-HE 660nm radiant efficiency is on par with Osram SSL and Samsung LH351H (~59% radiant efficiency) --- Hybrid lighting systems historically refers to mixing LEDs and HIDs to get the benefits of both. No idea what hybrid spectrum is, or how it could possibly be 'new'. What, multiple wavelengths? --- Ok. Back to COBs and QBs.

Thanks @Dr. Green Yeah if you don't mind a bit of risk, China has some great deals. I ordered one from Meijiu to test, because it did seem to be a better deal than my own lights :P But the sales lady marked the wrong price, and customs stopped it, and charged me R4500 penalty, and it took 4 weeks to get it released, and now it will take 90 days until they reply to my appeal, (and customs has always rejected my appeals). So there is risk. Customs is a bitch. It ended up costing a lot more than advertised, and two of my lights would have been much better deals, in this case. But if all goes smoothly, it'll take about 2 weeks, and you can save about R1500 over equivalent local lights by buying direct from China. My criticisms with the light, compared to my own lights, is the heatsink temperature, and the footprint hotspot. After half an hour, my infrared thermometer measured the hottest at 58 degrees C, which is pretty toasty, and the PAR measurements have a big spike in the middle, and trail off quickly. The datasheet shows that the 30 degree temperature difference reduces efficiency by about 4%, which is fairly substantial. The longevity probably suffers a bit too, but LEDs are pretty hardy. If anything, it's like they'll last 13 years instead of 14 years. I'm not particularly interested in reselling Chinese lights, but I'll see what the local market does. There's a couple of local competitors offering these 240W Chinese lights at R5999 (one on a stainless steel heatsink?! , and one has no information on theirs). Overall conclusion: Not a bad option. Bit risky.

Update: The extra 50W panel of warm white and red does seem to be doing a good job. (Off-camera, on the right). So I think underpowered QB panels on the side is probably a win. The strip light is probably not helping at all though. I think it still has its place in space buckets, but not in bigger areas. Just lacks intensity, and has poor efficiency. Couple of the plants starting to get cloudy trichomes, but still a week or two left for some of them. Just been defoliating any leaf that loses colour, every few days. Will have to work on my defoliation game.

Congrats Dank, 420th post in this thread!

Ok, did some defoliation, and added a panel of 50W of warm white & red side lighting. So, an extra 80W for the last couple weeks. Pistols are starting to redden, so it might have been a bit late for the strip lighting. Can't hurt though.

So, in the end, I've added 30W of strip light around the perimeter, in the lower canopy. I thought I was adding warm white, but turns out I added cool white by mistake. Oops. But should help anyway. Will likely add more side light this week too.

Starting to look pretty frosty!

@PsyCLown I've just had so little free time this last week, that the plants are just on autopilot for now. I've flowered under 4000K before. It's good for keeping the plants shorter. But yeah I'll add some warmer light, soon.

Thanks for the info, I think I'm gonna go for the side lighting.

I've got a little jungle going for my personal grow, about 4 weeks into flower. It's all drip fed on a timer, at about 1.2 EC, and 6.4 pH. Been away and haven't trained it at all, except for a few supercroppings before going away. Aurora Indica, GG#4, and "Bob Marley", under 180W of 4000K QBs. I'd like to up the lighting now, for the second half of flowering. Wondering how crazy to go with defoliation, and whether it might be a better idea to skip defoliation on the lower branches and instead add side lighting around the perimeter? Or, defoliate AND side light? Anyone have experience with side lighting? I've only done it in bucket grows. Not sure of the value of light hitting underside of leaves, and whether red would be best, or white. And defoliation, still a good idea at week 4 of flower? Thanks