Re: Hosted Competition - Haight Solid State vs. Hydro Grow LED
Hey SS,
PPl have chimed in about the Haight having the power advantage. But I think its a bit of an even playing field given the viewing angle on HGL's unit. What are your thoughts on that?
...This is just simple inescapable physics. The HGL light, with a narrower angle, penetrates better and sacrifices area, while the HSS light, with a wider angle, covers more area and sacrifices penetration.
With the HGL light, it's important to try to keep the plants in the "sweet spot" because light energy dissipates quickly outside of it.
The HSS light claims a much larger sweet spot, but depends a lot more on reflective walls to bounce light down to the lower branches.
I'm thinking that because the designs are so different, each light would work best with a different style of grow. The HGL light would work better for growing a few larger plants, while the HSS light would do better with a more horizontal SOG or SCROG style grow.
thanks DroJo! glad you're on-board bro!...
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...Hi TL!
looking forward to your info!
Thanks very much, SS! As promised, the following are some notes I've been putting together on this tech for my own use so as to make a more informed purchasing decision with LEDs. This also elaborates on
some comments I made earlier.
If anyone wants to understand the theory, caveats, and assumptions (and my own perspective/notes) I used for the below info, I've pulled this into a separate reference post so as not to clutter up this thread. That also has a link to the spreadsheet I did to create the estimates I used below. For those who want to check it out, here it is:
TL's LED Swipe File
So given a LED of the same wattage (or lumen output) and distance, but using different angle viewing lenses for dispersion:
A
60 degree lens will have:
• ~2.25x the intensity of a 90 degree lens;
• ~4x the intensity of a 120 degree lens;
• ~5.4x the intensity of a 140 degree lens; and
• ¼ (0.25) x the intensity of a 30 degree lens
Thus, I can understand why a 30 degree HGL unit can supposedly penetrate that much further than one of 60 degrees: a 30 degree (lens) LED at two feet has roughly the same intensity as a 60 degree LED at a distance of one foot (i.e. same intensity at twice the distance). The tradeoff is a smaller total garden area covered by the tighter lens LED.
First, I wanted to look at the
manufacturer's recommended coverage areas for each unit, in order to see how the dispersion fared in relation to the lens angle. I also ran the #s for the UFO style for comparison, as that is probably the most popular style right now. For reference, that is:
For the HGL and UFO lights, it appears the recommended coverage areas and distances are actually fairly accurate, looking at the dispersion the lights produce (see swipe file for definitions of the percentages used). The HGL light covers ~3 ¾ feet at 12" above the canopy (what they would consider to be their Primary Coverage Area.) The UFO covers a bit more than their recommended 4ft at 6" for flowering, and their 16 sq ft (vegetative) spread occurs between ~13"-14" high. For the HSS unit, the light actually spreads ~2m^2 (their 50" x 60" recommended coverage area) between 8"-9" high, a few inches less than the 12"+ they suggest.
(I also ran the #'s for the 63W Hydro Grow units in the .xls file, as I'm considering those also.)
Whether that actually translates into good growth at those distances is a different matter, however.
The next graph is probably the most interesting. It compares general dispersion of all three lights over the same 6 sq. ft. garden area, assuming one uses the best shape for that particular light (i.e. a circular garden for the UFO light, and rectangular gardens for the other HGL and HSS). I also added my 'ScrOG Special' (a 126W HGL unit with 90 degree lenses – the column labeled 'HGL-S') as another point of reference.
The tables above underscore
just how much changing the viewing angle for LEDs affects their overall dispersion (and, while this is not actual
intensity, it is directly related to it, certainly – see the swipe file notes for more on this) for each light. Even at 6", the HSS already
throws more than half its angle outside of the 6 sq ft area. While a fair portion of this can be redirected/recaptured with reflective materials, the recaptured light is also returned at reduced efficacy.
The more direct light we have at any particular distance from the light which falls in the garden area, the better.
By contrast, the regular 60 degree HGL ('HGL-N') unit still has
~all of its light directed within the 6 sq ft area at 12" above the garden. For the UFO, the sweet spot for ~6sf coverage is between "7-8" high; Mmmmick's garden is a good example of what kind of results one can achieve using a UFO light at these distances. Short (ScrOG) plants, and a close proximity to the canopy, are the best garden profile for wide angle lights like these. I think you, Butcher, Mmmmick, and a few others have all commented on LEDs being best used at short distances with ScrOG and short SOG gardens – and I would tend to agree.
The real differences in efficacy between lights become evident the farther away from the lamp one goes (i.e. when growing taller plants, most times). While the normal Hydro Grow unit still directs almost 1/3 of its light directly at the garden at 36" away (which would equate to what happens near the bottom of a 30" tall plant with the light positioned 6" from the top, for example), the Haight and UFO lights throw the majority of it to the sides, instead of at the garden, at these distances (again,
direct intensity is higher than this, but it (dispersion) certainly has a marked effect on overall growth – especially if the light is not recaptured). Which is probably why they
don't seem to be able to produce any real (significant) budding farther than 12" away from the top of the plants.
The swipe file has another chart showing how much area each light
tries to illuminate at each distance, but I think the point has been made. There are only so many watts to go around, obviously; larger (area) is definitely not always better, when one is talking about plant lighting...
(I also like the fact that the HGL units used a larger dimension light board than their counterparts (63W in 120 spaces for their smaller unit, and 126W in 288 spaces (i.e. 12 x 24)) with their narrow angle lens, helping coverage out a bit while keeping good intensity)
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For me, and as a longtime ScrOG convert, my preferred light (the HGL-S example) reflects a midpoint between good intensity for decent growth with plants with the primary budding areas at 12" or less above the canopy, and sufficient spread for proper garden coverage. Right now, this would take the shape of a custom HGL unit (in spectrum) with 90 degree lenses. I think a smart manufacturer would recognize enough of a market in these to make this a standard option for their lights.
You'll notice that a
60 degree unit at 12" covers almost the same area as a 90 degree unit at 6". Or, by raising the 90 deg. light another couple of inches, you'll illuminate another ~2 sq ft of garden area or thereabouts. This means that a 20-24 sq ft garden could be sufficiently covered by
three LED units, instead of four. For me, that's worth doing – especially if you're growing short plants. The 90 deg. light could also do a decent job growing short bushes (under 24" – the shorter, the better), and provide good coverage for mothers and clones on the vegetative side.
(While more light generally = better yield, a point of diminishing returns will eventually be reached, past a certain point, with any garden. Just as a 4'x4' garden may be ideal on a per square foot basis with 1000W HPS, by expanding that to 5'x5', you'll increase overall yield - with the additional 9 sq ft at the periphery simply contributing less than the primary area per additional s.f.)
That's where the intensity vs. distance discussion comes back into focus. While the 90 deg. lens is less than half the intensity of a 60 degree lens at the same distance, at
half the distance, however, the
intensity of the HGL-S at 6" is 78% greater per LED used (4/2.25), than the 60 degree lens at 12" (
while still covering the same area) for the area directly under the light, and slightly less than the 60 degree lens intensity (at 12") at the periphery. Which will translate into greater yield overall, provided there is enough space to spread out.
So, if you're using one light, and have sufficient room, the best yield would be with a 90 degree lens using ScrOG. Give me some additional s.f. of garden (even at a reduced intensity), and I'll give you more bud.
Or – get the 60 degree lens unit and keep it at 6" (if your garden's not much larger than the dimensions of the fixture), to really blast your plants with as much light as possible.
With the Pro units coming out Q2 2010 with 50%+ more lumens, that should only improve what a 'ScrOG Special' could do, IMO. At those intensities, we may start to see plant bleaching at 6" (60 deg lens), even; might as well spread it out and maximize the coverage instead.
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While the Haight light has 6W LEDs (which are less efficient in lumens/watt than 1W LEDs), to Drojo's comments, the 140 degree lens used is
less than one fifth the intensity at a particular distance than a 60 degree lens. So, the differences in intensity between HGL and HSS within the normal effective range above the canopy are probably negligible overall. There
may be some advantage for HSS very close to the light – near where bleaching tends to occur, perhaps. But once the plants get too tall (above ScrOG or low SOG level), the HGL wins the intensity/dispersion game, if not coverage per se, differences in wattage notwithstanding.
While 140 deg. lenses are good for automotive uses (such as a driver being able to see the brake lights in a wide angle when following behind a vehicle – a nice goal when considering safety), they're probably not so good for growing. I think HSS would definitely benefit from trying to change them out for something narrower – at least 90 degrees or so – which would more than double the current intensity at a given distance, and still allow for good coverage. Or make a 2nd product line, and market those to different customers depending on their specific growing style. That (90 deg) would be a nice compromise between low, short gardens and bush style growing, IMO. Provided those lenses are available for 6W LEDs, of course.
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If anything, I'd say this comparison is as ideal a scenario (outside of ScrOG, which would be ideal for HSS, and great for HGL also) to show what both lights can do (given that the plants should finish up at ~18"-22" high) as possible, and give the HSS a fighting chance as well.
Anyway, that's my present take on current LED tech. I'd be interested to hear what you think about it (and the manufacturer's opinions, as well, if they want to comment).
Thanks for the great job so far, SS! Keep up the good work. Look forward to the results, should be very interesting, in any event!
Regards,
-TL
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setting sun! seriously bro, i just caught up from the last couple days, and ur phenomenal. no question goes unanswered!
