X3 LED lighting for greenhouses

[WeirdGuySeattle]

Looking for a similar setup myself as I am having the exact same issues - mostly with my paphs (my Masdies do okay as do my Catts).

After doing some online research it looks like the pot growers (who seem to know their stuff) don't believe in the power of the 90W as a replacement for a 250W HID system (the common claim).

But I guess if you are just looking for something to supplement daylight might not work out so bad - I'd be running mine for about 4-5 hours a day, and I might need two to get proper coverage.

My main worries are that I would be competing with an electric heater for juice - but LED is going to be my best bet of not blowing my circuit. I've had issues in the past of running multiple electronics at the same time and the last thing I want is my whole greenhouse to go cold while I am at work or something when the circuit trips (usually trips at the socket in the greenhouse).

[littlefrog]

I'd really run another circuit for the heater... That isn't something to mess with. It is well worth the peace of mind. I'd rather be in the dark with the heat on, than everything going at once. If you aren't 100% comfortable running a line yourself, then for the price of a few nice orchids you can get a real electrician to do it. Seriously a good insurance policy, saving a little money up front isn't worth losing an entire collection.

When I built my grow room I put in three separate 20A circuits for lights (all on their own GFCI breakers) and a separate 220V for heating. I wish I had put in two more light circuits.

I think some 90W systems replace a 250W HID. Not all UFOs are created equal. I've bought a few 135W UFOs recently, they seem to be a pretty good investment for just a few dollars more ($10? It wasn't much).

[naoki]

Pricey, but illumitex has IP66 horticultural LED. Illumitex: LED Lighting for Horticulture and Architecture

I'm not sure which model they tested in the link below, but a illumitex model seems to have pretty good efficiency:
http://cpl.usu.edu/files/publication...b__4964212.pdf

[Lars Kurth]

After some investigation, and conversations with friends from the local orchid society who dabbled in LEDs (and moved back to fluorescent) I ended up buying a HID system. I now have 2 x 600W dual spectrum lamps with in splash proof fitting.

So far, this has been working fantastically well: normally all my plants would have stopped growing by now. This is due to my plot not getting any direct sunlight for 4 months (shade by surrounding tall buildings), short days (today's sunrise at 7:44am and sunset at 3:54pm) and gloomy winter weather (mostly dull and low cloud cover). If we have a bad summer, Catts often don't mature their previous years growth, Vanda's and other plants stop altogether for 4 months. This has not happened this year.

I do not yet know how much this will cost me though in terms of electricity. In the worst case, it will cost me GBP 30 a month extra based on 6 hours a day (the cost of a nice plant). The lamps generate a lot of heat when they are on and as a result, the heating does not come on at all when the lamps are on. So maybe the impact wont be as bad as I thought.

[WeirdGuySeattle]

well, I think I am going for two 240W LED lights for my 10X12 greenhouse - but will only mount them along my two main growing walls (my bigger non orchid plants in there can go dark...)

Its the local greenhouse outlet breaker that is messing me up. I suppose I could add another post in there, but lord that is a hassle... But you are right - much better to go dark than cold. having non flowering healthy plants is much better than cold and dead plants.

My main breaker can handle the load, I think the main deal is just to keep the water away from the outlets / plugs - this is what killed me last year.. I'll do some testing and if my breakers flip after putting on a full load (2 1000W heaters, 2 240W lights) - I'll start looking to install new electrical junk). Worst case, I have to unplug my lights during extreme cold... 2 heaters work with no issues, and I usually only run with 1.

[DavidCampen]

Originally Posted by naoki

Pricey, but illumitex has IP66 horticultural LED. Illumitex: LED Lighting for Horticulture and Architecture

I'm not sure which model they tested in the link below, but a illumitex model seems to have pretty good efficiency:
http://cpl.usu.edu/files/publication...b__4964212.pdf

Also interesting is the low efficiency of the Lumigrow LED fixture - about 1/2 that of the Lighting Sciences Group fixture.

[naoki]

Lars, for the seasonal use, I agree that it takes long time before LED become economical.

WeirdGuy, when they usually say that LED fixture is 240W, the actual consumption could be much lower. E.g., Blackstar 240W is only 160W or so. Sometimes, GFCI seems to trip easily when GFCI breaker becomes old. I had to replace a trip-happy GFCI breaker to deal with a moderate microwave oven. But 2000W heater on a 20A circuit is pretty close to the limit. I would guess that you can easily justify for an oil or gas heater, but the electricity might be cheap in Seattle.

David, yes, it was surprising to see such a big difference within LED fixtures. Lumigrow isn't so cheap, but efficiency seems to be very low. I guess that we have to be careful if we want to maximize the efficiency. You use nice, well-made diodes, but I usually play with cheaper Chinese stuff. So the efficiency of my LED stuff is probably pretty low...

[DavidCampen]

Originally Posted by naoki

David, yes, it was surprising to see such a big difference within LED fixtures. Lumigrow isn't so cheap, but efficiency seems to be very low. I guess that we have to be careful if we want to maximize the efficiency. You use nice, well-made diodes, but I usually play with cheaper Chinese stuff. So the efficiency of my LED stuff is probably pretty low...

It isn't only the diode, it is the quality of the entire design. If you want to minimize cost and don't care about efficiency then don't use an expensive constant current driver that has 95% efficiency; instead use a constant voltage power supply that then requires you to use current limiting resistors in series with your diodes and in addition use a cheap constant voltage power supply that is only 85% efficient. Also don't use heat sinks, LED efficiency decreases rapidly with increasing temperature, but heat sinks cost money

[WeirdGuySeattle]

I put up two 240W LED lights about a week ago - one 'vegetative' colors, one 'flowering' - the yellows / reds in the flowering spectrum are odd looking on the plants, but they should be fine. I might rotate the use of the two so they get even spectrum over time.

But I am pretty happy - only paranoid that someone will sneak into my greenhouse and steal them.

The power issues haven't really been a problem, all during 20-30 degree weather with both heaters going full blast all day.