InTheValley
Well-Known Member
humm cookie master, realllly???
and i agree on Los Reefer suggfest the thread independent. nice to
and i agree on Los Reefer suggfest the thread independent. nice to
Bad News About LED vs HPS
- Thread starter BobCajun
- Start date
mauricem00
Well-Known Member
I'm curious. what kind of yields are you getting with a 150 watt HPS I have a 6ft by 2 ft flowering closet and am thinking about adding a 150 watt hps next to my 4 ft T5 fixture in that closet.so I can add one more plant.2 ft T5s on the market have low quality ballast with B.Fs around 0.82. and this looks like an affordable option to fill that space next to my T5s https://www.amazon.com/dp/B01KMW7RYM/_encoding=UTF8?coliid=I16MXY1M60S5MV&colid=AW7UKM9ED6GM after searching you tube videos I found that even with high end LEDs some strains do not flower and those that do produce about 0.45 GPW. and that is using lights that cost $800-$1200. this HPS uses an enhanced spectrum horticultural bulb ( a little more blue).in this closet the extra plant would ged some light from the T5 but most from the HPS
BobCajun
Well-Known Member
I actually just started using them, due to burnout problems with LEDs and drivers, so don't know yet, and it's not pure HPS anyway because I added some LED "lightbulbs". Sorry I can't help you on that. But a 150 would be about right for the 2'x2' area in the end as you mentioned. BTW, when you screw the bulb in it's probably good to position it so that the metal rod that goes from one end of the arc tube to the other is angled upward or right at the top rather than on the bottom because it can block some of the light, being almost as wide as the arc itself. Kind of a bad design feature but I guess no way around it. I put it so it's not right at the top because most heat goes straight up and might make the rod very hot, which is probably not good.
Last edited:
Johnny Lawrence
Well-Known Member
I'm sorry, what???
mauricem00
Well-Known Member
https://www.1000bulbs.com/product/89342/FHO-49T5850.html mean lumen on these bulbs is 4625 and dropoff in no where near as fast as HIDs https://www.1000bulbs.com/product/91988/PLUSRITE-7318.html https://www.1000bulbs.com/product/91989/PLUSRITE-7319.html commercial quality bulbs and ballast do not have the price mark up we see and specialty stores or even the markup seen at home depot. I have money. I just don't like to waste it. many self made men treat the book " millionaire next door" almost as a bible and are proud of how fugal they can be.once I got into a discussion with some small business men who all had a net worth over $1000000 where people were proud about how old their appliances were or the fact that they drive their cars till the wheels fall off. for them money is just a tool for making more money.I'm 60 years old and retired but due to recient good fortune my income has increased by $30,000/year bringing me up to $100,000/year for sitting on my ass doing nothing. work my ass off all my life to get here but I still look for bargains and hate paying more than I need too. all forms of lighting have improved over time and the bulbs and ballast listed were developed for commercial applications. you may not find them at home depot but technology does not take long to become obsolete. in your proposed comparison grow I would bet on the cmh by a slight margin but it would be interesting.cheap Chinese led grow light makers are not the only ones who try to take advantage of us "dumb" cannabis growers
Johnny Lawrence
Well-Known Member
And small HID bulbs are really inefficient.
cookie master
Well-Known Member
by inefficient you mean you dont get a lb off a 250 watt right? but you can get an lb off a 400. Im being a dick by being argumentative but 315 is a small hid bulb.
CobKits
Well-Known Member
this
anything less than 600 DE really isnt even in the mix these days as far as hps
mauricem00
Well-Known Member
thank you. for $60 it's not much of a gamble and looks like a better option than anything else in that price range.also a good ideal to wear gloves when handling bulbs and wipe them down with a clean cloth to keep oil from your fingers getting on them which could cause them to explode
cookie master
Well-Known Member
he said hid, not hps. And I still like hps, I sometimes have plants 10 inches away from a 1000 due to height constraints.
Johnny Lawrence
Well-Known Member
Ummmm, no, I mean that they're inefficient. Do you understand what the word means?
Ceramics are different than MH and HPS
Rahz
Well-Known Member
There might be some Chinese LED grow lights that will only provide .45 GPW, but if by high end you mean high efficiency phosphor based LED you can expect 1.25-1.75 GPW depending on strain and growing method. I was pulling those numbers years ago using DIY lamps I wouldn't even sell now because the efficiency was under 50%.
Lamp 1- Vero 18 g5 @ 1050ma. My estimates suggest 35% efficiency. 700 output watts over 18 square feet. 700*.35= 245 PAR watts. 13.6 par watts per foot. Grown in hydro, yield was between 1.1 and 1.2 GPW from the wall. Best yield was over 2lb.
Average grams per par watt = 3.28
Lamp 2- Vero 29 g5 @ 700ma. My estimates suggest 42% efficiency. 350 output watts over 10 square feet. 350*.42= 147 PAR watts. 14.7 par watts per foot. Grown in hydro yield was between 1.4 and 1.57 GPW from the wall. Best yield was 21 zips.
Average grams per par watt = 3.57
I understand the efficiency argument has gotten old, but beyond that and the amount of energy we're throwing on the canopy we're really picking the bones talking about spectrum. Not that I think spectrum shouldn't be discussed but the difference a spectrum will make is a small slice of the pie. I know first hand the difference between CFL and 35% LED. LED won big time. Nothing else was changed, not even the strain. It was simply a switch out 600w of T5 for 700w of LED. Last fluorescent grow was 17 zips, first LED grow was 28 zips. Difference being the PAR wattage went up and the light that was being reflected before hitting the canopy went down. Even if we scale the LED down to 600w it would have been 24 zips. And that was under what I would consider a low efficiency LED by today's standards. I grew many times with those fluorescent bulbs and never got anywhere close to 24 zips.
Going by PAR watts alone I should have been getting at least 21 zips from the 600w of T5s, but I didn't. The reason probably wasn't spectrum, it's the fact that half the light had to hit a reflector before being directed to the canopy. That's the only reason I can think of for why my GPPW went up when switching to LED. That will also be true for other bulbs unless used vertically.
Last edited:
BobCajun
Well-Known Member
LEDs do have reflectors though, the back of the LED is reflectorized. Half the light presumably does bounce off that. I think much of the difference may be that LEDs run on DC so it's on steady rather than flickering on and off at house current frequency. An article about pulsed light mentioned than many light meters can't accurately read flickering light. The actual amount of light received by the plants could be considerably different than what the meter would indicate.
Rahz
Well-Known Member
LEDs can be fitted with reflectors but the back of the LED isn't reflectorized. Individual diodes are often fitted with tiny cone reflectors and/or lenses but this isn't true of cobs. Photons tend to leave the junction at 90 degrees from the junction surface but there is a potential 180 degree pattern.
In my case no reflectors were used. I ran cobs at 30 watts or less in an hexagonal pattern and kept the lamp 4-6" or less from the canopy during flowering. The last couple grows I was allowing the plants to grow up through the frame. I wish I had taken pictures of it.
Generally speaking cob LED should never need to be more than 14-16 above the canopy to minimize reflective loss. If someone is using cobs with 90 degree reflectors or lenses and has their lamp higher than that they're missing out.
In my case no reflectors were used. I ran cobs at 30 watts or less in an hexagonal pattern and kept the lamp 4-6" or less from the canopy during flowering. The last couple grows I was allowing the plants to grow up through the frame. I wish I had taken pictures of it.
Generally speaking cob LED should never need to be more than 14-16 above the canopy to minimize reflective loss. If someone is using cobs with 90 degree reflectors or lenses and has their lamp higher than that they're missing out.
OneHitDone
Well-Known Member
nfhiggs
Well-Known Member
Temps....
BobCajun
Well-Known Member
I guess you're right about no builtin reflectors in LEDs. Thought I read that somewhere but can't seem to find it anywhere now so obviously not a commonly reported part of LEDs. All I found was that about half the light just gets absorbed back into the LED and is the main cause of the heat. Got that from https://en.wikipedia.org/wiki/Light_extraction_in_LEDs. The light doesn't come out at 90 degrees though, meaning straight out, usually 120 beam angle.
From the rest of your post I see that my idea of less current but LEDs only about 6" from the canopy seems to be valid. As you said, the higher up, the more reflection, and photon collisions resulting in light loss by conversion to heat. You would actually want the light going as straight down as possible, so no reflectors and actually no COBs but instead individual mid power LEDs spread out.
I would also recommend having some of them pointing upward from pot level, because you really can't get much penetration from any artificial light source. When I turn my bottom lights off it's quite dark down there. It makes a world of difference, a bunch of dark compared to light everywhere. It doesn't even take that much bottom light to dispel the darkness. I 've got about 6w /sq ft down there, just two 14w bulbs, three was making too much heat for my liking and two seems to suffice.
Last edited:
BobCajun
Well-Known Member
True, the electronic ballasts raise it to several kHz, which is why they give off so much microwave interference, which then prompts the cable companies to come see what's causing everybody in the neighborhood's cable TV to be screwed up and trace it right to you. But I digress. It's still not steady light, as far as I know, just looks smoother to the eye. I don't know if flicker makes light less efficient for growing, it's just a hunch I had, trying to explain why LED seems to yield so much more than HPS of equal wattage. May have nothing to do with the power supply.
ZeroTrousers
Well-Known Member
LED yields more at equal wattage because a decent LED produces more useable photons per watt. It has nothing to do with pulsed output.
The because even the best HPS is only ~30% efficient at converting watts to photons.
Average LED is something like 40-47% efficient if properly cooled, the best LED can edge towards 55-59% when under-driven. There's also the argument that more light from LED is usable, but I'm not wholly convinced yet.