alesh
Well-Known Member
Are you really suggesting to use only 8.75W/sqft (4 CXAs) or as few as 4.5W/sqft (2 CXAs) ? That seems hardly enough for vegging. The tent is 4 feet by 4 feet.
DiY LED - Cree CXA3070
- Thread starter SupraSPL
- Start date
Skaumannen
Well-Known Member
30-50 W/square foot is the reccommended amount. So for 16sqft i would use a minimum of 10 cxa3070 @ 1400mA for a total of 520watts, or 32,5 watt/sqft. Other configurations are also possible, but i would personally not go above 1400mA unless you have dimmable drivers, and those are quite a bit more expensive.
reasonevangelist
Well-Known Member
I'm "suggesting" at least 4 for that 4x4 tent (it's enough @1A). But you don't have to pack the tent. You can grow a decent plant with just one cob and meticulous canopy management. I would *recommend more, but i'd say 4 is the minimum in that tent, if you want to saturate the footprint. My tent is half that size and i have 2 3070s @1A, and it is what i would call "enough," though ideally i would like at least one more, and to spread them out (currently using them together as a single light point... which gives enough intensity that the stuff directly beneath it in the "hot spot," is dominating the space, while the stuff on the sides is trying to elevate above the lamp; in other words, more than enough intensity in the center, but not enough on the sides... from just 2@1A).
4 will work fine if you evenly spread them, but of course, more would be better, to a point. 4 would work, 9 would be better. Many factors come into play, not just some watts per foot formula. All lamp watts are not created equal. Some configurations provide much more useful light per watt, than others, and different drivers are differently efficient, so you might be wasting power in multiple places... so if you're "using xx watts," that doesn't mean your plants are Getting "xx watts" of useful or premium light. If you used 4 cobs in a square, spaced at 40cm from each closest wall, and run them at 1A, you'll have "enough" light. Obviously more would be "better," but you also have to consider equipment costs, power costs, available amperage on your circuit, heat, etc.
The keyword was "minimum," in that i would want At Least 4, to adequately saturate a 120cm x 120cm footprint. Those cobs have a pretty nice intensity spread.
stardustsailor
Well-Known Member
This is one of SupraSPL's spreadsheets and it shows the lumen output of the cxa3070 AB bin at different currents (lm50c), i think these numbers are taken from some documentation posted by cree, but i am not sure about that. Maybe supra or one of the other users here can answer that one.
As far as i have understood most people stay between 700 and 1400mA, since this gives a decent price/watt with good efficiency. My setup is quite small, and i have more problems with low temperatures, so i opted for the higher amperage.
Stardustsailor uses a more efficient and dimmable driver for his builds (but more expensive) that can do 350-1950mA. Meanwell HLP-80H-42. Stardustsailor has made some really good looking lights, you should check out his thread "thinking of a new light" if you have not seen it already.
Actually the HLP-80H-42 it goes up to 2.1 A (2100mA ) ..
But this driver is 'bare' ..(open frame ) .
It needs to be encased ,otherwise it's heatsinks can give a nice shock ,if accidently touched...
The 'enclosed ' version of the same driver ,is the HLG-80H-42 ,which comes at double the price of HLP-80H-42 .
Cheers.
Greengenes707
Well-Known Member
Just put you cursor over the code(don't click)...then the whole code will pop up and you can read it.clicked that link... all the relevant parts codes are cut off. Everything ends with "000N0H" or "000N00." You have to click each thing to know which is which. If "AB30H" is what i'm looking for (3000k?), it says 20 min order quantity. So if you want to spend $900 on 20 of them, right on.(they're showing only 40 in stock, so only 2 people can order... unless they're willing to sell singles)
You could probably sell the AB 3000k's as singles for a decent bit more... i bet some people would be willing to pay up to ~$70 each for AB singles... not me though.
As for how they are ordered(20 mins)...that is the game we have to play. Just for thought...for a person trying to replace more than one 1000w hps, 20 isn't even enough. Plus there are plenty of people buying lots(20 to 100 at a time) and then selling spares...how do you think everyone on RIU is using only around 4(some more some less) in small grows...internet friends!(wow that is nerdy/loser sounding).
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reasonevangelist
Well-Known Member
Ah! I didn't even try hovering.
And yes, i managed to acquire "extra" Z4s (including a few relevant accessories) through alternative means, and i've been quite pleased with them. Pretty sure i'll end up w/ more at some point... just not ready for upgrades yet.
SupraSPL
Well-Known Member
It puts out about 1450mA once warmed up. Works great with most CXA3070, although it is cutting it close in terms of vF range. Hard to beat the economy of that driver. There is a 2.1A driver available but the vF range is even tighter and it cost $33. As you can see from the chart, as you increase the current the cost savings diminishes along with the efficiency. Heat also increases along with heatsink requirements. To mke matter worse, it is not possible to maintain a Tj of 50C when running at 2.1A. So 1.4A may actually provide the best economy when driver, heatsink and electrical cost are all taken into account.
The last column in the chart represents how much you are actually paying per photon when current droop, vf shift and temp droop are taken into account. But for the higher current levels, it does not take into account the Tj greater than 50C, so the advantage of running softer is greater than it appears.
The driver is consistently 90.5% efficient and is power factor corrected. Out of more than 60 drivers, I have not found a single dud, although I am sure there are a few lurking out there, it seems like there is some kind of extra quality control being used.
In summary, the eBay driver linked may be the best choice available for CXA3070 DIYers and it ships from Cali. I have found equivalent drivers but they ship from China and are more expensive.
Greengenes707
Well-Known Member
What's peoples thought/experience about 2 3070 in series...I know we have talk about it and when Vf don't match up great it could cause some issues. But just 2 chips in series...I think we can over come a little balancing. I want to run 2 3070 off one 1400ma version of... http://www.meanwell.com/webapp/product/search.aspx?prod=hlg-120h-C
FYI for people looking into cxa driver...those ebay drivers work great...at 12$ and 90+% efficient...i'll be take 6 more if my little plan here doesn't pan out...almost wondering why even try the meanwell other than the dimming.
FYI for people looking into cxa driver...those ebay drivers work great...at 12$ and 90+% efficient...i'll be take 6 more if my little plan here doesn't pan out...almost wondering why even try the meanwell other than the dimming.
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SomeGuy
Well-Known Member
reasonevangelist
Well-Known Member
The data sheet recommends against running them in parallel (think it's somewhere near the bottom).
I could definitely see dimming being useful. Even at 1A, you don't want those cobs beaming directly into your eyes, even peripherally.
bicit
Well-Known Member
Running the cobs in series is fine. Mr.Flux actually runs five parallel strings of five vero 10's wired in series. 25 cobs with a single meanwell HLG-185H-C1400. It's a pretty cool setup.
captainmorgan
Well-Known Member
I have 6 of them at 1.4 covering two plants in a 2.5x4.5=11.25 sq/ft space.
tenthirty
Well-Known Member
4 will do the trick.
Skaumannen
Well-Known Member
I have gotten some white tips on some of the top leaves on one of my two plants, and because i am a complete novice i am not sure if i am seeing early stages of nute burn, or if it is bleaching from the lights. So if someone here could be so kind to take a look and give me an expert opinion that would be much appreciated. It is a Nirvana Master Kush in soil, 17th day since flip, after 3 weeks of veg. Nutes i use are Canna terra (just started on the flower version), cannazym, and boost. And a calmag supplement . I have been using 1/4th to half of what it sais on the bottles of everything but the calmag which i have used full strength since i live in a place with extremely soft water. Watering every 2-3 days with about 1.5 liters of water.
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haha... no worries because of threads like this and your grows I'm seriously considering building some diy cob setups, some flower initiators (far red) and flower booster lights (deep red +UV).
btw Those hlg-120h-C for two cobs should leave enough Vf leftover to add a few Royal Blues, or cool white xml2s to keep the spectrum balanced.
churchhaze
Well-Known Member
If you talked about 730nm being a flower initiator 10 years ago, you'd have been laughed out of town.
It's amazing how what was once considered witchcraft is becoming conventional knowledge. Even though it was discovered over a half century ago, it took leds to make it easy enough for every man to test it for themselves, and thus believe it.
Now, everyone and their mother knows that 730nm during the day causes plants to stretch, and 730nm before night makes the effective night longer.
It's amazing how what was once considered witchcraft is becoming conventional knowledge. Even though it was discovered over a half century ago, it took leds to make it easy enough for every man to test it for themselves, and thus believe it.
Now, everyone and their mother knows that 730nm during the day causes plants to stretch, and 730nm before night makes the effective night longer.
true, funny tho cause the floral industry has been doing night interruption and light dep since I can remember ... way back in the 70s, my neighbors ran lights at night outdoors to control flowering of mums.
SomeGuy
Well-Known Member
Awesome. I could probably do 5 and cover the whole thing really well. I gotta finish my first led flowering with the bars I built before I go replacing the CMH for the 3x3.
I need to build a trigger @churchhaze. had no idea. Flowering came on a bit slower than I am used to but has picked up now.
I also have noticed a significant increase in density compared to what I am used to. All are rock hard regardless of size, even most of the undergrowth. crazy. LOL