Lighting Bilbo's Brief Guide to Choosing Your LED.

[Xagor]

In other words, it takes about the same amount of wattage in LED produce the same PAR output as HPS. The defining difference is heat and cost.

Leds generate light and heat from the energy you put in. Nothing else, correct?
If "a led" produces less heat at the same wattage as a hps, it must produce more light. As in the first law of thermodynamics, that energy can only be transformed, but not created or destroyed.

If this not the case, its most probably a crappy led light....like most what is beeing sold...
Thats why actual numbers are so important.
You can find a study in which many led panels are beeing obliterated by 1000W hps gavitas in terms of electric input/vs light output. By their calculations there will never be a return of investment bc the hps is simply better.
"Economic Analysis of Greenhouse Lighting: Light Emitting Diodes vs. High Intensity Discharge Fixtures"
However, it seems recent with the date of 2014, but most they use is quite old tech.
On the other hand, even with a crappy led heat can perceived differently -hps produces a lot of heat as rays (radiation, that directly heat the plants surface), while led transfers its heat to it heatsink (convection, ambient T raises more)

When I said that e.g. a certain Cree Cob reaches 48% efficiency at this and that current, it means 48% light output out of 100% energy input.
Usually HPS efficiency is about/ around 33%, reflector losses not included.
Thats an increase of 45% of PAR W/W... (but it gets a bit more complicated bc for photons there differences too -blue photon has more energy (but excess of energy cant be used), red photon has less, so blue is less energy efficient)

We all know the HPS spectrum is "wrong" but in terms of sheer light output and the driving of photosynthesis it works, it's tried, tested, and people KNOW how to use it...

I think its bc that photoncount (efficiency) > spectrum (as long as you get the desired results, nothing too much off/extreme)
And that green might be much better that many think..

 

[Mike-groglo]

there are lots of studies done that suggest that plants use far more of the spectrum than they are traditionally supposed to...especially into UV and mid spectrum areas...plants are very good at adapting quickly to an environment, and have natural work-arounds.

In other words, try as we might, plants aren't ready to give up all their secrets...something the scientific world is coming to terms with.

For the time being there are 2 camps...pro LED and pro HiD, and until there is a level playing field, we'll never ever change that, and until anyone can grow anything, under the same exact conditions, we will never get to the same results. And of course, that will never ever happen.

CoB, Diode, Lamp, corona discharge, they all do a job...

M

 

[A4]

there are lots of studies done that suggest that plants use far more of the spectrum than they are traditionally supposed to...especially into UV and mid spectrum areas...plants are very good at adapting quickly to an environment, and have natural work-arounds.

In other words, try as we might, plants aren't ready to give up all their secrets...something the scientific world is coming to terms with.

For the time being there are 2 camps...pro LED and pro HiD, and until there is a level playing field, we'll never ever change that, and until anyone can grow anything, under the same exact conditions, we will never get to the same results. And of course, that will never ever happen.

CoB, Diode, Lamp, corona discharge, they all do a job...

M

Mike,
I fall into the pro ME camp. I try to compare the data in an unbiased way to determine the most cost effective solution that meets my needs. I believe you are correct about the camps if you look at it from the manufacturer's side. Of course, depending on what one is selling, they fall into those camps but I believe for the most part growers want to use what is most economical and results in the highest quality yields. I have purchased LED panels in the past and they sucked. Granted this was in the infancy of LED grow lights but after being burned once for $1000 a person begins looking at details a little bit closer.

So, above I provided some independent lab results of LED and HID lighting. To me, looking at the data, it is hard to justify the extra costs associated with LED because the ROI isn't there yet. My question was, am I missing something? No answers. Instead, we talk about divisiveness, level playing field and biological theory. When LED came on the scene the manufacturers wanted to discuss everything in PAR because that seemed to be the most honest way to compare data. I agree and believe that puts things on a level playing field. Even in one of your previous posts you spoke about that as a level playing field.

So, am I missing something? I will reiterate, I WANT to purchase LED because with several thousand watts of lighting and another thousand in climate control my electric bill is absolutely insane. My problem is, with the data I have I don't see the benefit. Earlier in the thread, you spoke about testing your panels with PAR. Is that information available? What wattage your lights use comparing to PAR output at set distances? I haven't found it yet. I am not pointing the finger at you specifically because I haven't found it on GN's website nor Mars Hydro either. The thing is, if this is what we are going to use as the standard, and it appears to be, then where is the data to compare apples to apples?

 

[Mike-groglo]

Hi A4

all the information is available online. We PAR test over a 1m wand giving accurate averaged PAR readings over the entire metre, Every unit that is produced as from the end of the month is now supplied with PAR readings at 60, 80, 100 and 120cm readings, we tried to integrate it earlier but we're so busy with the research stuff and new products...you get the picture!

Overall we usually arrive at around 280-300umols in a non reflective environment at 1m dependent for a 600W unit depending on model. Attached are pictures.

Note... picture 1 shows set up in chamber not necessarily height ...while picture 2 shows the setup for measuring...we're just in the process of making this setup a little less Heath Robinson and more permanent, picture 3 shows the reading for a 400RB/200P at 1m (all heads on) the "spread" shows the amount of change over the entire wand...

In terms of power usage our 600W (and I can't speak for anyone else here) uses around 311-314W from the wall. The full phosphor a little more, the RB a little less.

Hope that helps...

 

[Xagor]

On your hp you write:
Roughly equivalent to a 1200 Watt HPS or HID lamp, this lamp is suitable for an area equivalent to 5.76 Sq Metres. This model pulls 312W from a 240VAC socket and around 2.72 amps.

If said hps has about 33% PAR Efficiency going from about 1200Watts, (DE HPS are even much better now), it puts out about 384Watts PAR.
Your Led has a power draw of 312W, not speaking PAR...

1. So your light must be more then 100% efficient and produce energy out of thin air
2. it must produce literally zero heat.
3. to beat a 600W HPS with about 200W PAR it must be about 64% efficient, which I think is very doubtable.
4. Why does the casing of your COB look exactly like those generic 4$ alibaba/ebay Cobs?
5. Sorry for sarcasm, what am I not seeing?

 

[HubbaBubba]

I don't know where this discussion is going, but I am glad it is still going!

Is PAR per Watt a reasonable way to compare lights? (from a grid of measurements)

 

[A4]

Is PAR per Watt a reasonable way to compare lights? (from a grid of measurements)

I believe that is the most accurate way to test right now. Even HID manufacturers don't like to use PAR for a standard because they say that hoods have an important part to play in how much PAR is directed at the canopy. To that I say, well start designing hoods and you can control those numbers, until then, quit crying.

Everyone, including HID manufacturers like to try and confuse or dilute the conversation with technical jargon and theory but at the end of the day it seems everyone has agreed PAR is the most important spectral range of light for photosynthesis. So it only makes sense to compare Watts being used to PAR being generated. Everything else is snake oil in my opinion. Then you should apply costs of unit vs expected lifespan. Most LED has a quoted lifespan of 50,000 hours. I don't know how accurate that is but regardless, if you use that number and operate the lamp on 12/12 then it gives you a lifespan of about 11 years. When you consider using HID over the course of 11 years at 12/12 then you are looking at about 22 bulbs. That alone brings the price range for HID back up to the cost of LED.

From all the data I have crunched, it is about a break even deal right now when you compare all costs associated with owning HID as compared to owning LED. IF LED lasts the 50,000 hours they claim. I don't know how anyone can know that yet because they haven't been in the market long enough to make those assumptions and we all know that LED has had some serious issues early on with heat prematurely degrading and compromising components.

My biggest complaint in this whole thing is, if someone is going to make claims about being able to replicate a certain bulb then show me those PAR numbers. I did notice MARS Hydro yesterday posted all of their grid PAR readings for the latest light in a video. That was nice to see. It wasn't even close to what a 600W HID will do but hey, at least they put the data out there for people to see. If everyone did that I don't believe we would see the constant flame wars and arguing because the data cannot be refuted with slight of hand marketing campaigns.

 

[minime]

Is hps 33% PAR efficient? I could have sworn it 33% of the power gets converted to light, which is not exactly PAR.

I have no scentifuc background but just look at lighting, LED and HID are both pretty good for white light efficiency. But I'm sure alot of that gets wasted in useless spectrum. Having a dialled in spectrum is where i think LED growing makes it up along with not having to reflect the majority of its light, trouble is all LED lights differ so makes it a minefield.

 

[Xagor]

Is hps 33% PAR efficient?

Yes and latest edition - DE doubled ended bulbs are even much better...

But I'm sure alot of that gets wasted in useless spectru

The accepted standard in plant science is the mccree curve:
https://smartgrowtechnologies.com/wp-content/uploads/2014/12/par_light_mccree_curve.jpg
Looking at the spectrum of a hps there doesnt seem much to be wasted, right?

Diagrams showing a lack in the green region are BS!

Most LED has a quoted lifespan of 50,000 hours.

For Cree you can find this:
http://www.cree.com/~/media/Files/Cree/LED Components and Modules/XLamp/XLamp Application Notes/XLamp_lumen_maintenance.pdf
If you go deeper, you can find data for all of their leds.
Basically they put all of their leds into test chambers and run them 24/7, by measuring their values they predict the lifespans in mathematical models -up to now led follows these modells accurateley.

 

[A4]

@Xagor

Do you actually grow anything? or just bang on about shit? I bet you are a ball to go to the pub with...

C'mon man, there is actually a pretty decent conversation going on here. No need to stoop to personal insults. As Mossy said earlier, keep it civil.

Whether he grows or not is irrelevant, he is contributing to the thread and from what I have read most of his information is accurate. Almost all of my research in organics has come from non canna related people. I didn't need them to grow canna to tell me how to achieve a decent soil. I needed them to understand soil biology.