Math behind LEDs

Growroom Design
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#1

LEDs are lately able to offer superb results. Being pretty conservative in deciding what works and what not, I’ve tried to do some math.

I’m comparing NeoSol F3 520w to HPS 1000w because that is what manufacturer Illumitex states on the website as direct replacement.

Purchase price

520w Neosol … $1,325
1000w HPS (1000 Watt Double Ended (DE) 8" Hood Reflector Kit) … $290
Difference in price is $1,035

Costs of operation

Savings of using 520w instead of 1000w in 12/12 cycle during 365 days (so 4380 hours lights on) (I know I’m omitting some overhead that HPS has in power consumption)

4380*0.480 ~= 2100 kWh

Price of electricity is pretty high in Europe compared to US - about 18 US cents per kWh.

So total savings per year of using 520W Neosol instead of 1kW HPS is 378 USD.

1,035 / 378 ~= 2.74

=> It takes at least 2.74 years until I start to get any benefit of costs saving with Neosol. Pretty long period still…

Of course this case applies to cold parts of Europe, we’ve got problems with heat only 2-3 months in year (many times instead of adding Air Conditioning it is better to just switch off during hot summer). We usualy have lamps on in night when they can get more easily cooled by outside air. Also there is usually possibility to use waste heat from separate lamp circuit to heat another growroom, house or living areas.

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#2

Couple of things to also consider are two bulb replacements for the HPS which if you want to go for the best are about 130 US each adding 260 to the cost. Also if you are a commercial farmer the LED not only save about half the electricity they also produce twice the product at the same wattage. In some cases 4 times the product at the same wattage.

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#3

P.L. Light says that two of the company’s 320W Hortiled Top fixtures can replace one of their 1000w DE lamps, each one costs twice as much as the 1000w, so the initial cost is about 4x higher with LED. At this point they don’t suggest that LED will ever pay off for commercial greenhouses. The HPS bulbs only need replacement every 2.5 years.

But there are some other advantages, the LED"s can be dimmed as needed when the sun is shining on the greenhouse, etc. Also the commercial industry is using these as supplemental lighting, the LED’s have far better spectrum for sole-source lighting.

The PAR output of a commercial-quality LED is better than the same PAR number of an HPS light. Up to 80% of the light output is at the red point on the spectrum where maximum photosynthesis occurs, where HID’s spread the light over all of the different PAR wavelengths. This is why you get some amazing yield results with commercial LED spectrums specifically designed for cannabis.

Right away I noticed the 320w Hortiled lamp seems to penetrate down into the canopy and lower flowers as well as my 600w HPS did, even though it looks dimmer. It’s not dimmer to the plants, they love the red light, whereas the human eye sees yellow and green 5 times brighter than red or blue. It’s the opposite for plants because photosynthesis evolved deep under the ocean where most of the green & yellow is blocked by the seawater.

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#4

I have grown under 400w (price cca 250USD+ with quality reflector)

Soon I will try LED - 4x 3500k, 200w - homemade by one of local grower, looks really proffesional, upgradable - (price cca 670 USD) - something like this https://overgrow.com/t/led-300w-4x-cree-3590-3500k-max-75w-wilma-8xl-6-5l-air-pots-sour-diesel-riri-cut-homebox-100x100x200-par/819

I’m curious about the differences between 200wLED & 400wHPS. I mean, it makes sense… due to electricity prices in Europe. In our small country LEDs are experiencing boom.

96x 5,4w leds does not inspire much trust in me… I doubt it will fully replace 1000wHPS, but maybe I’m wrong.

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#5

Thanks for your input, guys!

Good point… Changing HPS bulbs every 12 - 18 months should be calculated in to be fair…

That is why I calculated two variants that manufacturer officially states, so that it is comparable … They offer 520w LED as one-to-one replacement of 1kw HPS.

Can you be more specific which LED lamps have 4 times yield?

That is right! That is clear advantage…

Yes, in US electricity costs are probably only 1/4 fraction of EU prices…

#6

You should also add in the crazy ass price they made you pay. You can get a led light nowadays that out preforms a 1000w for waaaaaay less then that. To build a 600w led itll cost you about 5-700$ depending on shipping and deals. And that 600w will put out more photons then the light you used.

Most of these commercial leds have a good chunk of price added onto then for the build and shit. Then they use semi good parts to save some cash but still sell it as if they used all top quality gear.

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#7

LJ, there are two different types of HPS bulbs - those than run at 200v, and those that run at 400v. (internal voltage within the fixture, not at the wall).

The 400v bulbs from Philips and Usio (600w and 1000w) last MUCH longer than the others. At 2.5 years they are 92-93% of maximum. The commercial fixtures from companies like P.L. Light and Gavita use these bulbs. When people refer to the advantages of double-ended bulbs, most of the advantage comes from using the higher-volt bulb, not the anchoring of the bulb at 2 ends.

here’s an example of the 600w bulb - you can see at 10000 hours (2.4 years at 12/12) they’re still operating at 93%. The failure rate reaches 10% at this time, so 2.5 years is a good time to replace. You could run even longer at 90%+ much longer if you don’t mind having a bulb go dark now & then.

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#8

here’s the brochure for PL Hortiled. You can see where the high price comes from - they’re using state-of-the-art Osram diodes, the red ones reach 3.0 umol/J efficiency. The Cannablum spectrum Hortiled Top runs at 2.7 umol/J efficiency. The best HPS run at 1.9 umol/J.

Then when you look at the spectrum, the Hortiled is delivering 80% of that 2.7 umol/J at the red point on the spectrum where the plants most efficiently photosynthesize. I recommend reading the Univ. of Utah stats and report on lighting if you’re interested. This chart shows you how much light each type of HID lamp puts out.

Univ.Utah_Growlight_spectral_characteristics.pdf (1.3 MB)

So my old Gavita 600w HPS used to run at peak of 1190 umol/J, and the 320W Hortiled top is 850 umol/J. But it seems to penetrate and yield very similar to the 600w. Even though the PAR is a bit lower, way more of that 850 umo/J is focused at the red where plants want it, and 10% precisely where they like the blue. HPS only has 5% at the blue, and most of the red light is actually orange or deeper red where plants aren’t as efficient.

and HID ballasts eat up 10%, so a 600w is actually 660, 1000w is 1100, etc.

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#9

Here’s the full report - I like the chart on page 3, it actually shows COB lights on the graph too.

Univ.UtahFULL.pdf (1.0 MB)

Here’s some more LED info from Philips, I’d love to run their top lights but they require 240v:

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#10

OK, if you want to further geek-out on the light data here is a great illustration of photosynthesis and the spectral points with highest efficiency. The McCree PAR curve that gives us the umol/J and PPF benchmarks just lumps all the light between 400 and 700nm into the same bucket for measuring.

But the plants use the blue and the red much more efficiently, so commercial fixtures like Illuminitex, PL, and Philips use diodes that blast those points on the spectrum with light. The plants only need 10% in green/yellow, where HPS and even CMH put a shitload of the light. So the advantage won’t necessarily show up by just comparing PAR benchmarks.

http://hyperphysics.phy-astr.gsu.edu/hbase/Biology/ligabs.html

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#11

Not sure how to see the quote when using this software so I’ll just answer in here.

I am not sure who makes an HPS bulb that lasts beyond a year that does not have severe degradation starting at around 9 months. Certainly not going to be getting results in an HPS bulb at 18 months or 24 that will even come close to a real deal LED grow light, I.E. Illumitex and or Fluence Bioengineering at 24 months. I own both…

Both of these lights run circles around HPS watt for watt with the SPYDRx PLUS edging out the Illumitex mainly just due to the overall wattage being 550 VS 685 so not really an apples to apples comparison.

I have been able to obtain close to 6GPW on two of my strains that are both in the 23+%THC levels not some ordinary swag like grow in a lot of “commercial” outfits around the US that pump out volume.

I’m sure most people would call BS but there are at least 2 maybe more people at this very site who watch me on the daily put out these types of numbers on the regular. Previously to that I was at an average of 1.7 with my custom built lights I created in 2009.

Training plants for LED lights is also key and not the same as growing with HPS.

Couple of videos of commercial LED grows.
https://www.youtube.com/watch?time_continue=2&v=WU1OwgbjzEY

https://www.youtube.com/watch?v=5w8wCzTroUI

https://www.youtube.com/watch?time_continue=3&v=RJyuYcTxtuU

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#12

love the Fluence videos. they use white diodes with some extra 660nm diodes to boost the red. There’s a lot to be said for working under white lights vs blurple, especially for hobbyists who like to stare at the flowers all day :smile:

It’s no joke about the longevity of 400v HPS bulbs, they absolutely crush the usual 200V EyeHortilux and others on durability. With legalization you can just call these people up and talk to them, I’ve really enjoyed hanging out with the guys from Urban-Gro at conventions and talking tech with them.

They told me the next run of PL Hortiled LED’s will come out in about 5 years and move the efficiency from 2.7 umol/J to about 3.1. The diodes are still getting more efficient but the pace has slowed down. They mostly sell PL’s 1000W NXT HPS fixtures so they’re more honest about the LED hype. For the cheapest cannabis sole-source lighting they currently recommend a mix of HPS and CMH or a mix of HPS and LED. I believe P.L. Light currently has a 75% market share of worldwide horticultural lighting. the company is called Hortilux in Europe.

http://urban-gro.com/grow-light-solutions/cannabis-lighting-products/

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#13

That second video. When the girl described the trichome, “Its like a fairy sneezed on them.” I almost spit out my coffee laughing. :joy:

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#14

Check out my pictures in the Bud Shot closeup thread. You’ll see what she is talking about.
:stuck_out_tongue_winking_eye:

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#15

Salutations,

Dumb question, maybe:

Why not make it really “VERTICAL” by penetrating the canopy all the way down, with thin LED stripes exploiting the space between 2 perpendicular banches?.. On top of that i suppose water cooling would contribute to passive circulation as hot water would move to the top, etc.

Good day, have fun!! :peace:

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