New LEDs for my grow room

[DelawareJim]

A member of my local aquatic plant club ran across a new LED vendor called "Build My LED". Build My LED Custom LED Lights for DIY Horticulture Aquarium Hobby Lighting

After visiting the site, I was intrigued because they had both horticultural and aquarium systems and you could design you own. Looking at the design you own option, I discovered they list their LED emitters by spectral wavelength, plus a couple of "white", and by beam angle rather than by perceived color temperature as everyone else does. You can also generate a report to show expected spectral analysis, PAR, lumens, efficiency, power consumption, etc. he also has a link to a study NASA conducted back in 2004 on green-enhanced lighting which is a really interesting read.

A quick email with some questions and the owner calls me back. It turns out, he has a background in horticulture, and worked for a top horticultural lighting company designing lighting systems for research facilities of some of the biggest names in the horticultural industry. He decided to leave all that and start his own company. We discussed some of the latest research in light and photosynthesis, and then about some of my plans for an LED system for a seed starting set up and for growing emersed aquatic plants in empty aquariums (for humidity), getting dimensions, planned fixture height above the plants, etc. He then sent me some 3-D PAR models to show how some recommended lights would light the setup which I posted in the club forum.

Here's the complete thread:
GWAPA • View topic - Buildmyled.com

All that said, the guy knows what he's about and for anyone looking into LED's, in my opinion, this is THE place to go.

Cheers.
Jim

[DavidCampen]

That is a nice looking product. Still it is $5 per watt compared to $1 per watt for an equivalent water resistant fluorescent fixture fitted with specialty grow bulbs. The price still needs to come down by a factor of 2 or so to be generally competitive with fluorescent plant growth lighting.

I would consider buying these LED fixtures instead of building my own for applications where I want a narrow beam angle. I would have to verify though that he is using the same definition of beam angle as I expect which is the total interior angle (called FWHM, Full Width Half Maximum) and not 1/2 the interior angle. Also, his most narrow beam angle is 30 degrees while for my applications I use optics with a beam angle of 14 or 22 degrees.

One minor nit, he lists the output of the fixtures in micromoles, which is nice, except that I presume he means micromoles per second.

Edit:
A more major criticism, just like every other vendor of one of the new types of lighting, he is making ridiculous claims about the type of lighting he sells being so much more efficient than other types of lighting.

Here he claims that 260 watts (input power) will replace 660 watts of HPS. I say that that is bull.
4'x4' Horticulture Lighting Design | Build My LED - Lighting Discussion Forum

[DelawareJim]

Okay...Maybe you can solve my conundrum then.

My current flourescent fixtures I use in my grow room are dying of old age. They're lighting various orchids, house plants, seedlings and tissue cultures.

Specifically, I have a grow chamber where I need a completely new lighting system that will not raise temps more than 5 degrees above ambient temp in a sealed box approximately 48" x 24" x 60" high. I would prefer lighting in 450-500 nm and 630-700 nm wavelengths, and could produce as much or more useable light whilst using less electricity as we recently de-regulated and my electricity rates are almost doubling.

What do you recommend?

Thanks.
Cheers.
Jim

[DavidCampen]

If you can afford them then these LED modules will work. If you use 460/660 nm LEDs (only 20% or 25% at 460 nm) then you may be able to use 2/3 the wattage of T8 or T5 fluorescent; so 80 watts of 460/660 nm LED replaces 120 watt of T8 or T5.

Do you have the existing fluorescent fixtures outside of the case? I would guess that you do. The LED fixtures at 2/3 the input wattage will produce 2/3 the heat. The narrower beam spread LED fixtures would likely be advantageous.

[ronaldhanko]

Very interesting, Jim. These are looking more and more like the choice of the future.

[escualida]

That's pretty expensive, I just bought a light from this seller on eBay, they manufacture LED grow lights in China and ship them directly from there. They are really, really good quality.

LED Grow Light, Bulk Order items in ledgrowlightmanufacturer store on eBay!

It took like 4 days for the light to get here and is SUPER powerful, way more than I need but I'm happy with it and the plants are blushing and doing well. They have built in fans and the temp doesn't go up very much, obviously it would depend on the strength of light you get.

[DavidCampen]

Originally Posted by escualida

That's pretty expensive, I just bought a light from this seller on eBay, they manufacture LED grow lights in China and ship them directly from there. They are really, really good quality.

LED Grow Light, Bulk Order items in ledgrowlightmanufacturer store on eBay!

It took like 4 days for the light to get here and is SUPER powerful, way more than I need but I'm happy with it and the plants are blushing and doing well. They have built in fans and the temp doesn't go up very much, obviously it would depend on the strength of light you get.

A 600 watt LED fixture with 200 3watt LEDs for $400! I find that hard to believe. 2 watt to 3 watt LEDs from a reputable manufacturer, LEDs only- no housing or power supplies, will cost you $1.50 each in lots of 1000.
High Power LEDs - White | Mouser

[escualida]

I don't know what to say to that, I'm not lying, and I have absolutely nothing to gain, I have no association with that seller.

All I can say is that you'd be buying straight from the manufacturer in China. I have the light and like I said, i'ts very bright, is built very well and seems to be high quality, and my plants are doing well with it so...

[DavidCampen]

To continue on about why $400 is an unbelievably low price for a 600 watt LED panel.

Let's assume that we got a really good price on 3 watt LEDs - only $1.00 each. So the 200 LEDs will cost us $200

You can't supply electrical power to LEDs directly from the wall socket. You need an LED Power Supply to convert AC line voltage to DC and regulate the voltage to maintain constant current. Here are some good quality LED Power Supplies from a Taiwan based company:
LED Power Supplies | Mouser
As you can see, a 300 watt power supply is about $150 each in lots of 50 and you will need 2 of these for your 600 watt panel for a cost of $300.

So just for the LEDs and power supplies we have a cost of $500.

This is not all. A 600 watt LED panel will be producing about 400 watts of heat and LEDs do not like to get hot so you will need a substantial heat sink and fan arrangement to get rid of this heat; very easily another $50.

So we easily have a cost of $550 just for materials, even before we begin assembly.

Also, if we want the light from the panel to be reasonably focused, say a beam spread of less than 60 degrees, then we will likely need a lens for each of the 200 LEDs; another significant cost over the $550 material cost that we have already identified.

[bethmarie]

have just starting experimenting with LEDs. Appreciating the chance to learn more in this thread. thanks for the posts.