Southern California has a messed up electrical system. you would think that with ALL that sunshine they could harvest enough to get the electric rates down. I mean shoot they don't even have to heat water with electricity.
Top bin COB comparison
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flaxseedoil1000
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It's actually the reverse, they mandate 'green energy' production which is more expensive and the costs get passed on to us. 
nogod_
Well-Known Member
It's actually even worse. Their rate is a completely made up number. They can charge whatever they want and do. Monopolies work!
It's actually the reverse, they mandate 'green energy' production which is more expensive and the costs get passed on to us.
flaxseedoil1000
Well-Known Member
In Cali rates are regulated and approved by the California Public Utilities Commission.
http://www.desertsun.com/story/tech/science/energy/2015/11/02/southern-california-edison-electricity-rates-change/75050098/
Getting off topic but it illustrates why some of us avoid MH and HPS
http://www.desertsun.com/story/tech/science/energy/2015/11/02/southern-california-edison-electricity-rates-change/75050098/
Getting off topic but it illustrates why some of us avoid MH and HPS
agree, that's why its messed up. the mandates don't work and subsidies have minimal effect. The power companies don't like net metering and are against distributed power systems since they can't control the power source and charge for it.It's actually the reverse, they mandate 'green energy' production which is more expensive and the costs get passed on to us.
wietefras
Well-Known Member
Great find!
So that means that Gavita measured their own light in a tent which they feel is best suited and then measure 803umol/s/m2 average over 2m2. Or in other words, starting with 2100umol/s from the bulb there is a loss of light from the fixture and walls of around 24% (1600umol/s left). Or 8.5% to 11% loss from the walls if we consider measured fixture output figures between 1750 and 1800umol/s. So around 15% loss for the reflector and 10% for the reflective walls to round the figures off a bit.
Stephenj37826
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Also the reflector in that test was hand built and supposedly the numbers are slightly better on production units.
BuddyColas
Well-Known Member
So I usually sit on the sidelines and watch the fray, but I had to ask. Could a regular customer get those results? The tent is a beta version and which version of their production lamps would get a similar pattern? Just asking...because that is an impressively uniform pattern...especially considering that all those photons come from a single source.
I like that the tent is a major player in their pattern. I grow with COBs in a 2'x4' cabinet and the walls are a big part of the equation...really the "second reflector" for the COBs.
Stephenj37826
Well-Known Member
I'm thinking so. This is with there new wide throw reflector. It's genius really build the grow room around your light pattern. I mean who besides them sells a 1.1x1.8 meter tent? I'm thinking a led builder could design a tent specifically for there light and get similar results. Using different combos of lens/reflectors at varying bream angles one could probably get similar results.
Stephenj37826
Well-Known Member
so this is a case where the light needs to come with its preferred walls (tent) to be fully effective. pretty cool its a system.
Stephenj37826
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Still wondering about yield . We all seem to be pretty fixed on photon count being the biggest factor concerning yield as far as lighting is concerned. With that said they seem to be getting 1.6 umol/j+ to the canopy in this instance. It seems that if spectrum plays only a minor role in yield then we should see similar results from this setup as we would with say cxb3070 3000k ab bin at 1.4a if its evenly spaced with lenses and some wall losses. Should be within 10% in a controlled side by side. Thoughts?
BuddyColas
Well-Known Member
Thanks for the prompt response. I like Gavita reflectors. I have a Triplestar 600 I tried with my 2x4 cabinet. The pattern beat any other HID reflector I tried for uniformity. I sure don’t have the engineering budget of Gavita, but what I have especially liked about COB DIY is that I can change and “tweek” things and learn by experience (COB 101 is now in session!).
I have 4 each Vero 29s on 2 each 40” bars. They hang independently. It has been a real education for me as I take canopy PAR measurements and move the bars closer and further from the walls. Then I tape and untape (Kapton) the COBs and try different spacing down the heatsinks. Not a fast process, but very educational. So when I saw that PAR print from Gavita, I was impressed.
Having tried many HID configurations in my growbox, I really like the COBs. I run them about 25-30 watts each, about 8” above the canopy with no reflectors (so the walls are important), and have a very uniform 700umols at the canopy with very manageable heat. Heat on the canopy and in the box is not even an issue anymore. And I save at least a third in power costs over running my old 400w HPS. I know I’m preaching to the choir here.
wietefras
Well-Known Member
EVERY grow room should have reflective walls. Otherwise you are simply throwing light away that you could have kept at a very small investment.
@Stephenj37826, Spectrum really plays a role in yield and product quality though. Simply counting photons is not enough. Red and Blue leds have been shown to perform slightly better in growing tomatoes than daylight or "PAR" led spectrums. Adding FR leds also help increase photosynthesis and resulted in higher dry matter percentages and higher BRIX numbers (better taste). Results might be different for cannabis, but I doubt it.
The HPS spectrum isn't optimal either though since it's too low in blue (less than 5%). So leds (with a better spectrum) actually perform better per mol of light when compared to HPS.
I switched from Gavita's to COBs trying to match light output, but I ended up with 20% more light. Mostly based on how the distribution of the COBs fit in the grow area and my desire not to spend too much on the leds and therefore a minimum of 1.4A current. So I got 20% more light and ended up with a yield that was 30% higher per mol of light.
I'm assuming that spectrum helped the leds perform better, but also the better light distribution. The light from the COBs is also much more diffuse (many points of light spread out) resulting in a better light penetration. Tests in greenhouses have shown that diffuse light can increase yields by a few percent as well. Around 4% IIRC, but that was compared to sunlight which is extremely direct. I also had better control of the temperature lower in the grow area with the leds.
Stephenj37826
Well-Known Member
30% better yield per umol at a higher ppfd? Now that my friend is an accomplishment!
alesh
Well-Known Member
It might seem counter-logic but I'd say that conventional tight beam lenses won't provide better penetration that bare COBs. Would you agree?
littlejacob
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wietefras
Well-Known Member
@Stephenj37826, Sorry that came out wrong. I had 20% more light and 30% more yield in total. So only slightly more yield per mol.
Tight beams will increase "depth", but only because they bundle the light into a smaller area. You will then have to hang more lights to cover the whole area and in the end you will have simply increased the total amount of light. Remove the lenses and/or reflectors and you will eliminate the losses they incur thus creating even more "depth".
I haven't tested it though, but I feel certain enough of this that I have no desire to test it.
That is, if you have reflective walls to at least reflect the light that hits the walls back. Otherwise reflectors and lenses would most certainly help you get more light on the plants. Reflective walls seem like a cheaper alternative to me for a small hobby grow room. For commercial table grows with walkways around them probably not so much. Although they should make sure they don't waste so much light on the floors. Don't have walkways everywhere and put the tables on wheels:
Yeah I agree.
Tight beams will increase "depth", but only because they bundle the light into a smaller area. You will then have to hang more lights to cover the whole area and in the end you will have simply increased the total amount of light. Remove the lenses and/or reflectors and you will eliminate the losses they incur thus creating even more "depth".
I haven't tested it though, but I feel certain enough of this that I have no desire to test it.
That is, if you have reflective walls to at least reflect the light that hits the walls back. Otherwise reflectors and lenses would most certainly help you get more light on the plants. Reflective walls seem like a cheaper alternative to me for a small hobby grow room. For commercial table grows with walkways around them probably not so much. Although they should make sure they don't waste so much light on the floors. Don't have walkways everywhere and put the tables on wheels:
cdgmoney250
Well-Known Member
I have tested this.
Reflectors and/or lenses create much more usable light at depth (penetration) than a bare COB without any optics (proper spacing).
The difference is pretty significant.
COB's throw light damn near 180 deg. in all direction and even reflective walls don't redirect enough of the photons back towards the canopy. I would only run bare (EDIT) COB's if overall height/ light saturation was a concern.
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Stephenj37826
Well-Known Member
this was discussed on the diy tech talk just today....... I also believe optics/reflectors is a must unless you are height restricted.
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