DiY LED - Cree CXA3070

[Positivity]

I'll be doing a simple test in the future with my UVB. Just leave it off completely and compare same strain same nutes. The insane stickiness this round could be due to other things...need to find out. But as of now I think the UVB is a solid addition. If I leave it off and I lose considerable stickiness, which I consider a major indicator of quality, then I'll know well enough for me.

for me efficiency is of course important . But it all comes down to the final product, I shoot for the highest quality possible every time. Anything not up to par gets turned into hash.

what kind of UVB did you try out supra? Probably a wide variation in performance.

reccommended is 250uw. I just ran it full 12hrs all the way....stickiest batch ever in 20 years of indoor...coincidence?

sometimes testing and breaking from the norm is what it takes

 

[SupraSPL]

I believe it was the zoo med reptisun 10.0, either an 18" or 24". At the time I was working with a small space and I kept the UVB tight on the canopy. I agree that premo product is the goal but I have found that genetics, temp control, growing media, correct fertilization and optimal drying are the keys to good weed. LED takes it up another notch I can verify that in my favorite cuttings that I have run so many times.

I still have the UVB stashed somewhere maybe Ill track it down and test it again someday.

 

[Positivity]

Hard to make solid conclusions on things like that. So many variables with everything..

did manage to order some 3070s in 3k and 4k. Looking forward to trying those out in the future...couldn't resist. Decided on 1a drivers for now. Thanks for the info on efficiency, I think that will be a good current to work with. It will allow me to add other colors to the string if I feel the need. I'll run it all white first though.

Also going to try out the ideal connectors and ledil Angelina reflectors. 50 degrees is narrower than I'd like but I like the design so I'm gonna give it a try. Really like the ledil Lenina xw at 72 degrees but only fits the cxa 2011 at the moment.

 

[captainmorgan]

I believe it was the zoo med reptisun 10.0, either an 18" or 24". At the time I was working with a small space and I kept the UVB tight on the canopy. I agree that premo product is the goal but I have found that genetics, temp control, growing media, correct fertilization and optimal drying are the keys to good weed. LED takes it up another notch I can verify that in my favorite cuttings that I have run so many times.

I still have the UVB stashed somewhere maybe Ill track it down and test it again someday.

I've read that the older zoo med bulbs weren't the best quality but the new T5 HO reptisun 10.0 UVB bulbs are now German made and are as good as the Arcadia's now.
My plants using 5 to 6 hours of UVB are also extremely sticky too.

 

[RedCarpetMatches]

I saw that a long time ago and it convinced me to try UVB. It turned my trichs brown which I don't prefer and there was no magical increase in potency unfortunately.

Redcarpet the most efficient small white LED that I know of is the Cree XM-L2 U2 4C (4400K). It is 45.5% efficient at 1A (3W) and cost $1.52/Watt. Very impressive but the color temp is not ideal for growing IMO.

So for warm whites, the Cree XM-L2 T4 7A3 (3000K) is 36% efficient at 1A (3W) and cost $1.61/Watt. The Cree CXA3070 3000K that we have available to us is 42.5% efficient at .7A (25W) and cost $1.76/Watt.

So in regards to warm white, the CXA3070 COB is much more efficient than the XM-L2. The COB is also much more convenient to install.

Thanks once again. Are you calculating these efficiencies? I like the spectrum of the 3070s, but feel they're lacking a bit in 660nm. What do you cerebrals think?

Where's the spectrum for the 3070 2700k's?!

 

[CannaBare]

I've had great fat trich heads with UVB CFLs! Coulda been the strain. I've read that they produce more trichs for protection from harmful rays. I need a refresher course on the matter.

Anyway, since all this is about efficiency. Are cobs more efficient than 3w diodes?

EDIT: where's the spectrum graph for the 2700k? I only see the 3000.

You have to be imaginative for the 2700k. for me I just shifted the graph over a little because I am mostly interested in the 630nm and 660nm being covered well.

 

[CannaBare]

Hard to make solid conclusions on things like that. So many variables with everything..

did manage to order some 3070s in 3k and 4k. Looking forward to trying those out in the future...couldn't resist. Decided on 1a drivers for now. Thanks for the info on efficiency, I think that will be a good current to work with. It will allow me to add other colors to the string if I feel the need. I'll run it all white first though.

Also going to try out the ideal connectors and ledil Angelina reflectors. 50 degrees is narrower than I'd like but I like the design so I'm gonna give it a try. Really like the ledil Lenina xw at 72 degrees but only fits the cxa 2011 at the moment.

I do not know if people are willing to hold off but I took the plunge today and ordered 100 3070 in 2700k color spectrum, Performance class Z2. They will ship within a month.

Just getting the info out there

 

[caretak3r]

Dismantled a bunch of computers a few month ago. Never thought I would be looking for heatsinks shortly after. They were the nice big Pentium II sinks also. Just salvaged a couple.

speaking of heatsinks, i went searching for one with enough surface area to mount either 2 decent size cobs, or a cob and some supplemental stars. I picked up one of these:
http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&LH_BIN=1&_nkw=(771,lga771,dempsy,woodcrest)+(heat+sink,heatsink)&_sop=15

for $10 shipped. It's a nice chunk of copper (660g). I know it'll need active cooling, but I bet it does well for the price.

 

[RedCarpetMatches]

I do not know if people are willing to hold off but I took the plunge today and ordered 100 3070 in 2700k color spectrum, Performance class Z2. They will ship within a month.

Just getting the info out there

FIRST DIBS!!! I'll PM ya

 

[CannaBare]

FIRST DIBS!!! I'll PM ya

Sounds great ill put you on the list! Ill send a pm when they arrive!

 

[PetFlora]

Very cool

Too bad they don't list heat dissipation in the title

Now, if they would only mount them with quality cobs

speaking of heatsinks, i went searching for one with enough surface area to mount either 2 decent size cobs, or a cob and some supplemental stars. I picked up one of these:
http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&LH_BIN=1&_nkw=(771,lga771,dempsy,woodcrest)+(heat+sink,heatsink)&_sop=15

for $10 shipped. It's a nice chunk of copper (660g). I know it'll need active cooling, but I bet it does well for the price.

 

[Chronikool]

speaking of heatsinks, i went searching for one with enough surface area to mount either 2 decent size cobs, or a cob and some supplemental stars. I picked up one of these:
http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&LH_BIN=1&_nkw=(771,lga771,dempsy,woodcrest)+(heat+sink,heatsink)&_sop=15

for $10 shipped. It's a nice chunk of copper (660g). I know it'll need active cooling, but I bet it does well for the price.

Good find bruv...

I just got my 350mm x 350mm x 5mm plate yesterday....the basis of my new veg light....awesome surface area....what was even better is that it was a favour that was owed to me...

....no money down

 

[RedCarpetMatches]

This thread really brain fucks me good. Anyone know which reflectors are best for these cobs. I'm sorry if it was already mentioned. Also, if you have 700ma constant current drivers...why the need for a driver each pair? I plan on two...maybe three 4' heatsinks with a driver each. Thanks in advance geniuses.

 

[smokey the cat]

Anyone know which reflectors are best for these cobs. I'm sorry if it was already mentioned.

I was really interested in reflectors etc too until I actually assembled my light and realised how directional LED is compared to ye olde bulb teqnologie. The spread of them might be a lot less than you expect - ymmv, ianal, wtfbbq. Looking at the other recent DIY builds on here I see the same thing - hang a cob a foot above your canopy and there isn't much lost light to worry about. I'm not expecting to see many builds use reflectors.

Ledil look like go-to option for high quality reflectors if you're interested. http://www.ledil.com/products/?search=true&led=CXA30

Also, if you have 700ma constant current drivers...why the need for a driver each pair? I plan on two...maybe three 4' heatsinks with a driver each.

One driver per emitter - so you might have 4 driver+emitter combos on each heatsink..
Other option is the pricey high voltage models from MeanWell (hlg-185 etc - danger: high voltage!) to run 2-3 cob in series, or benchtop/lab power supply (ebay secondhand) which is the only safe way to run cob emitters in parallel.

 

[CannaBare]

This thread really brain fucks me good. Anyone know which reflectors are best for these cobs. I'm sorry if it was already mentioned. Also, if you have 700ma constant current drivers...why the need for a driver each pair? I plan on two...maybe three 4' heatsinks with a driver each. Thanks in advance geniuses.

It is better to run them on their own because if one goes out your in trouble. Also the voltage would be very high. I think Mellodrama posted earlier about a reflector holder for the COB. Chip-lok?

 

[spazatak]

It is better to run them on their own because if one goes out your in trouble. Also the voltage would be very high. I think Mellodrama posted earlier about a reflector holder for the COB. Chip-lok?

really you cant run them in series and have one go out and the others workd... thats a whole lot of drivers if you run 6 of them together

 

[RedCarpetMatches]

Thanks for quick responses! I seen those reflectors you linked. I personally like spreading the light around, and hitting diff angles...or just more cobs lol. There's gotta be a way to not have ugly drivers everywhere. I got some looking to do.

CB...where's my damn cobs already?! I have a trick up my sleeve for UVB

 

[SupraSPL]

Awesome score Cannabare! I was planning on grabbing 100 CXA3070 3000K top bin Z4 that popped up on arrow but someone beat me to the punch. 2700K top bin Z2 sounds even better though, where did you find them actually available?

 

[SupraSPL]

Thanks once again. Are you calculating these efficiencies? I like the spectrum of the 3070s, but feel they're lacking a bit in 660nm. What do you cerebrals think?

Where's the spectrum for the 3070 2700k's?!

Yes I am calculating them in a spreadsheet with the help of Mr Flux LER numbers. Our numbers are very good for qualitative comparison among LEDs with similar spectrum and probably good enough for a quantitative comparison. But our numbers are only as good as the data Cree gives us and we are using the minimum figures, so I expect slightly higher performance. We are dependent on Crees SPD curves and they look pretty generic compared to the very specific curves Luxeon gives us.

You can also use the Cree product characterization tool to estimate these numbers but we are still dependent on the generic curves for the LER. LER is the only way to calculate radiometric efficiency. The efficiency number is helpful to compare one LED or LED lamp to another, although wavelength has to be taken into consideration along with efficiency.

 

[SupraSPL]

speaking of heatsinks, i went searching for one with enough surface area to mount either 2 decent size cobs, or a cob and some supplemental stars. I picked up one of these:
http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&LH_BIN=1&_nkw=(771,lga771,dempsy,woodcrest)+(heat+sink,heatsink)&_sop=15

for $10 shipped. It's a nice chunk of copper (660g). I know it'll need active cooling, but I bet it does well for the price.

Very nice heatsinks!