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shopping looking to buy LED light, opinions?

HPS is more efficient than any LED. Cree has an LED that will do 150 lumens/watt, but nobody can afford it.

If LED is so efficient, why don't you see them on the interstate highways? They're still using HID because they're more efficient.
 
Lighting up a patch of highway is a LOT different than lighting up my grow shelf.
Like I said before,know your light sources limitations and how to use it.

In the space I have to grow stuff in HPS isn't going to work for me.
Heat as it is is a big problem.Add to that my space limitations and HPS is just not practicle.
 
HPS is more efficient than any LED. Cree has an LED that will do 150 lumens/watt, but nobody can afford it.

If LED is so efficient, why don't you see them on the interstate highways? They're still using HID because they're more efficient.

The town I work in recently switched all the streetlights over to LED. It can be done.

Smokemaster: you said earlier that you can run multiple 30v strings on a single driver, as long as the mA isn't exceeded. To do thus would I run the strings in series, and then link them together in parallel?
 
I think they run the strings paralell with drivers.

I've never used a driver.

I use resistors and LM317.

1 resistor and LM per string.Parallel.
Negative is common to all strings and the positive lead from the supply goes to however many lm's I'm using on that board.
Maybe next time I make a supply I'll take pics.
I was going to do a step by step at one time but people weren't interested or started posting about how LEDs sucked or whatever so I didn't bother.

I use 12v , 12amp. computer power supplies. playing with a 24v ,2.5amp supply too.

Actually,using a higher amp. and voltage supply would be better than what I'm doing but I don't like running 50 LEDs in a string.1 goes out and you gotta find it to replace it.I'd rather have a short string go out where I don't have to fix it right away or my plants go without light.
Then,LEDS don't always break the circuit when the smoke comes out.A lot of times they short so your string gets more volts per LED.If you are already running your LEDs at med. or higher voltages.The volts might get high enough to take out others.
LEDs aren't cheap...


The LM's use 3v +/- so I'm actually left with about 9 volts per string.
It'll run about 50 1 watt LEDS.

I was told that computer power supplies are stable enough that I probably could just use resistors.
I read somewhere that you can put a transitor of some kind in between each string so if an LED fries it shuts down the power so you don't take out other LEDs when the power goes up...
It was on either the DIY or instructables site.

At one time I was thinking about buying a commercially made LED Growlight just to gut it to see what they use for a power supply.

PS.
ALL the stop lights around here are LEDs.BUT thats different than lighting up a street.
All the motorhomes and a lot of cars now have LED tail lights etc.
They are VERY much brighter than they used to be.
They do have specially made lens covers so the LED light isn't a bean,it's spread out.
From what service tells me.You can't use an old style lens on your brake lights etc.The old ones don't diffuse the light enough or something.
A tech here said that they are working on LED headlights too.Comming soon...
All of the above is still a lot different than lighting up a large section of highway(without blinding drivers)with an even amount of light.
I do see a lot of LED spots for home use/backyards etc., being sold but I haven't heard if they can compare to halides or whatever.
 
I think LED tech has merit. I was at one of the largest automotive part tradeshows a couple of weeks ago and saw several LED headlamps. Here in Germany you can also buy full 1.5 meter long LED T8 bulbs in several color options.

I have one small commercial array in my grow tent, and I swear the plants that sit under that light have a much fuller canopy than the others.

Like with many things, tradition dies hard.
 
I haven't had any problems with getting superhots to pod up under LED grow light. What matters is PAR(Photosynthetically active radiation) and the wavelengths the diodes run at.

You need to get wavelengths for both Chlorophyll a and b. At the peak absorption values for most performance.

Lumens is not a correct way to measure how effective a LED grow light is, PAR is the best measurement out there now that I know of. Choosing light by it's wattage is deceiving.


Light_9.gif

Chlorophyll a peaks at around 440nm and 660nm.
Chlorophyll b peaks at around 460nm and 640nm.
The green/yellow part is pretty much just reflected by the plants and has little use.


At least that's what I think I've learned from spending countless hours going through hundreds of different lights and reading details in depth. I can still be wrong though hehe
 
So, I'm looking for an affordable LED that can stand up to a 250w HPS but use less electricity. What lamps have been tested by you? Where is the best place to put my money?

http://www.sunshine-...p/gp1-98567.htm

I saw this online, but find it hard to believe that 28w of anything can compete with my current lamp.

Help me out!

28W is 28W, whether 80% of that goes towards light in the appropriate spectrum for growing or 95% does, it's still just 28 Watts and cannot possibly compete with 250w HPS . So you're quite correct in being skeptical, a quick glance at luminous efficacy numbers at wikipedia will tell you there's not a great deal of difference between HID and LED, if anything gas discharge bulbs outperform LEDs in lm/W. As has been pointed out this isn't the only consideration and lumens aren't all that counts, but still your 250 HPS will outperform a 28w LED every time both in growing your plants and saving you money.

Plus I don't like the color, it looks like a ufo. :)
 
28 watts can produce a lot of different lumens.

Depending on the light source and how you are running it.

1 watt LEDs can put out up to about 100Lumens max. each.

So you can run more 1 watt leds on the same watts(volts X Amps.) than you can run 3+watt Leds of the same lumens.

SO 28 watts is 28watts BUT if you are running different LEDs that put out the same Lumens for each LED,you can get more Lumens out of more 1watt LEDs than you can from 3+ watt leds using the same 28 watts.

28 watt driver.

1 watt leds at 2.5volts , 300ma , 80lm each

3 watt leds at 2.5volts , 600ma. 80lm each.

A 28 watt driver will run 2 x more strings of 1watt leds (in this example),2x the lumens , than 3 watt LEDs of the same Lumens..

Volts X amps. = Watts.

Most adds with watt comparisons are pushing how fast or slow different light sources spin your meter to get x amount of lumens or whatever way they are choosing as a measure of light to pry the $ out of your wallet.

Most stuff is only partially true or taken out of context with a lot of facts omitted for sales purposes (with all light sources in general)

I see a LOT of comparing apples to oranges going on in most adds.

I remember when the common FACTS were that Fluoros could never get a plant to bud and set fruit...
Nobody told my plants that I guess...

Not long ago they said the same thing about LEDs...

I never used HPS because of heat problems.
I have no experiance with them.

But 1 watt LEDs are doing just fine for me these last few years.
Nobody told my plants that 1 watt LEDS just don't work.

As with any light source,you have to know what you are using and their limitations.How to use them...
 
...

But 1 watt LEDs are doing just fine for me these last few years.
Nobody told my plants that 1 watt LEDS just don't work.

As with any light source,you have to know what you are using and their limitations.How to use them...

Sure LEDs work, hell - even NASA's used them for growing plants. The question here is really about how a 28w LED panel compares to a 250w HPS in performance and cost-effectiveness. If you have very specific goals such as using the least amount of electricity possible and stuff like that - because you're, for instance, in space - then LEDs might be the way to go. But I'm going to need a lot of convincing that that 28w LED panel can replace a 250w HID light. That's like saying a little sliver of relatively expensive mylar can reflect just as much light as a nice, big and cheap aluminium-foil-covered wall.

But other than that, I'm sure there are a lot of benefits to growing under LEDs and not everything is always about minimizing cost, not at all. :)
 
Any light source has it's good and bad points.
Depending on your needs one is going to be better than another for your purposes.

My point was that most times I see adds and people saying that how fast your meter spins is supposed to mean your light source is better or worse than each other for whatever reason they want to give the customer.

I don't compared different light sources in general.
My T8's were way too hot,hotter than my t12's.
T8's didn't come in the K I like either.

Halides are even hotter.
Compact Fluoros were too hot also at the time...I didn't like the K selection either.

My only choice was to go to LEDs.
I have always made my own panels.
Probably a lot different than some of the snake oil I see being sold on the net.

I started with cheap 5mm LEDs to mess with colors etc.
Once I got my colors working I went to stars,now I am playing with 1 watt 10mm LEDs.

I use the 5mm Leds for verticle lights around my plant.

Actually I think using verticle light works better than horizontal.

With LEDs above the canopy gets too thick.
With side lights I get branching very early and hand sized leaves etc.
But that is another post...

This plant was a seed on July 22.

Demon Habanero.

IM004952.jpg


IM004954.jpg



IM004953.jpg
 
we should have a list of led panels that work and what ones to avoid that way when people google it they come here.

It's a good idea but I don't think that would work out too well, anyone can come up here, post a couple pictures of their product and say how well it works. It would just devolve into an advertisement campaign imo.
 
It's a good idea but I don't think that would work out too well, anyone can come up here, post a couple pictures of their product and say how well it works. It would just devolve into an advertisement campaign imo.

Maybe have a vote (they would need to crate an account to vote)
 
Maybe have a vote (they would need to crate an account to vote)

Well, to have a vote or a poll, you'd need relatively few options and a significant number of people voting. There are numerous LED panel suppliers and very few people who use them, so you'd have a hard time drawing any conclusions, let alone statistically significant conclusions, from such a poll if you could even create it in the first place. Which suppliers will you incude? Which will you disregard?
 
Probably wouldn't work too well.
An example is some of the vendors on the vendor area have turned their reviews into an add for their products.

I Think a lot of companies buy LEDs from whatever source is cheapest at the time...U.S. , Hong Kong or wherever they get their LEDs from.

I doubt they even test their LEDS against the data sheets to see if that batch measures up to the last one or any other batch they have used.

I've read about people getting great results from a companies panels where others say they sucked.
Same co. , same model panel.

I think the difference is how the panel was used and probably how good the last batch of LEDS were that were used in any particular batch of panels.
Also the drivers ,if they change just a little in MA. and or Voltage will change an LEDs output.
Heat has something to do with an LEDs output too.
It's possible to get different outputs from a panel if it's used in a 75 degree room or a 95 degree room.


At the same time,with all the Dazzle them with brilliance or baffle them with B.S. going around in adds.
Most people still wouldn't know what to believe before buying anyway.

Like fishing lures,some catch fish,others catch fishermen and look real purdy in ma tackle box. :)

People that spent a gazillion $ on a $30.00 panel will just keep quoting the b.s. they bought into on the adds before getting their panel.
Some people like lots of scientific looking mumbo Jumbo to show people about stuff they have.
 
I saw smokemaster's LED setup in person and I have to say I was very impressed with his results. His demon Hab was greener than anything I have ever seen, and the plants growing on his window sill with a supplemental led panel were going crazy too. This man definitely knows what he is talking about when it comes to LEDs, so listen to what he has to say.
 
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