Led vs Cmh

CobKits

Well-Known Member
CD bin is 171 lm/w, 52.5% efficient @ 23.5w via integrating sphere data. I doubt DB numbers are anywhere close to what you suggest.

Best I can infer from @CobKits's graphs is 1 PPFD/w @12" = 5% efficiency. I got this number because from another graph I found CXB3590 CD @ ~23w = 10.5, divided by 5 = 52.5 which matches real data. If my estimations hold any weight then most flagship chips nowadays will be 50% efficient at 50 watts.
that sounds reasonable. the "factor" i used in the past was right around 6 when everything was pegged to 56% theoretical efficiency of cxb at 1400 mA

the sphere should be more accurate/repeatable. those numbers are always 20-60 ppfd/W as were aggregating all light instead of just a spot reading.

upload_2017-3-27_20-12-12.png
 

REALSTYLES

Well-Known Member
that sounds reasonable. the "factor" i used in the past was right around 6 when everything was pegged to 56% theoretical efficiency of cxb at 1400 mA

the sphere should be more accurate/repeatable. those numbers are always 20-60 ppfd/W as were aggregating all light instead of just a spot reading.
me
View attachment 3914573
I have Cree cobs for $39 and you guys don't want to sell them for that price and we are getting everything from the same suppliers.I'm done with the bs we are playing lets help people.
 

Leandrobcool

Active Member
200w would be extreme for a 2x2. 300w would be about right for a 3x3 but you could go with less and still get good results. I'm working on a 181w output LED lamp for a 2x2 tent. It will provide 1350 PPFD at full power. In a 3x3 it will provide 600 PPFD. Using 4 Vero 29 at 1.05 amps (280w) you will get about 870 PPFD which is really good. If you used 6 Vero 29 at .7 amps (270w) you will get about 920 PPFD.

600 PPFD PAR will provide you with about 75% of a plants photosynthetic potential. Close to 1000 will provide you with about 90% photosynthetic potential. For comparison a 1000w DE bulb will provide around 800 PPFD in a 5x5'.

You can check these links for LEDs and drivers. I haven't done any research myself on it but it should point you in the right direction.

http://www.meanwell.eu/distributors.aspx
http://www.bridgelux.com/where-buy#emea-(europe-middle-east-africa)
But why u say that 200w is too extreme for a 2x2 tent, is too much Light for tge plants, to much heat?because I also have a 2x2 room and I was thinking to use it with it from time to time..
 

CobKits

Well-Known Member
But why u say that 200w is too extreme for a 2x2 tent, is too much Light for the plants, to much heat?because I also have a 2x2 room and I was thinking to use it with it from time to time..
too much light. it can work but can also cause problems for a lot of people. you have to have everything dialed to run at high ppfds like that. it can be done. most people would do just as well if not better with 120-160W in that same space
 

CobKits

Well-Known Member
I have Cree cobs for $39 and you guys don't want to sell them for that price
its not that i dont want to.... nobody buys them. the few CXBs i have on my site are from last year and are listed for sale for less than my cost as i bought them right before the price fell out. Its not worth it to stock cobs where the margin is so thin that you lose your ass everytime the market shifts. They're fine cobs and definitely work well, we know this. if there was even one tiny bit of special sauce that made it worth the extra cost i could justify it, but at the end of the day its just another phosphor-based cob and branding really means nothing to me. efficacy per dollar means everything to me and many others
 
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TacoMac

Well-Known Member
CMH hands down.

It's tried, true, 100% reliable, a known factor.

LED's are so variable, unknown, with so many differing opinions and very little documented fact that you really don't know what you're getting in the end.
 

CobKits

Well-Known Member
Very interesting, this chart is for 80 CRI i'm assuming, does the placings change with 90CRI? more specifically how is a CXM-22 90CRI compared to a CLU048-1818 90CRI? and how does a CXM-22 stack up against a gen 6 1818?
those are all 4000k 80 cri except for the cree which is is 70 cri as i didnt have an 80 at the time, so its handicapped a little. at the time cree 4000k 80 was CD bin, its in DB now i have new chips from cutter on the way and will be doing another round of testing with all the newer chips.

to answer your question, all of these chips use similar phosphors to get their colors, and they should scale similarly in another test of all the same color/CRI, the one exception being the spectrum is slightly different in some cases between manufacturers in a given color so thats not really apples to apples. all of the measurements i do are direct PAR measurements so for our purposes its probably slightly more useful than lumen measurements as were not correcting them to PAR with digitized multipliers, thats automatically accounted for.

i havent had a chance to test the 1818 gen6 yet but if it scales the same relative to gen 5 as the 1212 did, its probably right in the same range as cxm22, and if i had to guess it would pull ahead slightly above 80W. just a guess
 

CobKits

Well-Known Member
CMH hands down.

It's tried, true, 100% reliable, a known factor.

LED's are so variable, unknown, with so many differing opinions and very little documented fact that you really don't know what you're getting in the end.
LEDs are actually pretty well understood if you stick with known parts. its real hard to find people who arent getting 1.4+ g/W on their first try with modern cobs and thats a little above the unit per CMH (350W at the wall) that people get when their system is dialed. plenty of people on here that are approaching 2 gpW with COBs though that sort of efficiency has a capital cost (which is a lot cheaper now than it was a year ago)- youre gonna be north of a $1 per watt on a DIY build which is kinda right where CMH is over 4 years with a bulb change after 2 years

CMH are great though, better than HPS imo
COBs are also great
 

Rahz

Well-Known Member
But why u say that 200w is too extreme for a 2x2 tent, is too much Light for tge plants, to much heat?because I also have a 2x2 room and I was thinking to use it with it from time to time..
At 50 w/ft a good cob lamp is going to be hitting over 1400 PPFD. There's no reason to hit those numbers. Maybe with CO2 and the right strain but I'm guessing most 2x2' tents aren't getting CO2.

However, the cost difference between a 150w lamp and a 200w lamp may not be much so it's possible to justify putting a 200w lamp in a 2x2 and dimming a bit. It's not something I think a person should feel like they need to do thought. A good 150w cob lamp will do really well in a 2x2 and adding more light isn't going to increase the yield much if at all. The lamp I currently sell for a 2x2 is 136 watt output and it provides 970 PPFD.
 

REALSTYLES

Well-Known Member
I don't worry about high PPF or PPFD because of my organic soil remember guys I use to be a master grower for dispensary that I quit, if guys forgot lol. My best grow was 23lbs indoors 10k HPS in rock wool

KNF for the win

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TheChemist77

Well-Known Member
ive been running the 315 watt ceramics for alomost 3 years now,,love them,, ive hit 1.4 gpw on my first run now im at 1.6 gpw average... i bought 2 100 watt go green citizen clu048 1212's a few months back.. wright now u can get 4 100watt citizen's from go green for 600 but if u use riu20 code 4 cob's are 480 bucks.. 4 100 watt cituizens will easily cover a 3x3,, but a single 315 watt cmh will also get great yields in a 3x3... cant really say which is better, cmh or led,, but i like both,, if i was starting growing today w/ all my knowledge i would p[robably go with the ceramic,, only because good led's havnt been running for years n years how long will the cob last? with cmh i know to replace the bulb every 2-3 years and it will last for many years,,reliable.. that said ill tell u in 10 years if these cobs are still performing....
 

Leandrobcool

Active Member
At 50 w/ft a good cob lamp is going to be hitting over 1400 PPFD. There's no reason to hit those numbers. Maybe with CO2 and the right strain but I'm guessing most 2x2' tents aren't getting CO2.

However, the cost difference between a 150w lamp and a 200w lamp may not be much so it's possible to justify putting a 200w lamp in a 2x2 and dimming a bit. It's not something I think a person should feel like they need to do thought. A good 150w cob lamp will do really well in a 2x2 and adding more light isn't going to increase the yield much if at all. The lamp I currently sell for a 2x2 is 136 watt output and it provides 970 PPFD.
But if dimm them to 100w wont i have the best efficiency working 4cobs @25w, or is it "wasting" cobs?
Or even to 150w?
 

Rahz

Well-Known Member
But if dimm them to 100w wont i have the best efficiency working 4cobs @25w, or is it "wasting" cobs?
Or even to 150w?
Dimming will provide better efficiency, but there's no difference between a 4 cob 150w lamp and a 4 cob 200w lamp dimmed to 150 watts.
 
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