LED Floodlight - Experience ?

[Tschimm]

Hi there

A well known breeder told me, LED-floodlights could be an affordable alternative to all those pricy growlights.

Specs would be (example in the pic below)
-100 Watt
-8500 Lumen
-either 6000K or 3000K
~50.000h

Anyone here who tried one of those ?
Anyone here who would ? (Or would'nt :-)

imagesource: ledlager.de

[naoki]

It probably depends on the design of the particular model. If it is not well designed, the efficiency may not be better than florescent light. There is a DRAMATIC difference in efficiency among LED fixtures; e.g. which LEDs and drivers are used, what is the driving current, how the heat sink is designed etc.

If it is similar to one of the cheap ebay models, it probably isn't so efficient (or I should say that their are better ones). You can grow plants.

I was initially interested in these cheap ebay flood lights, too (due to very cheap price). I did a bit of measurements of those ebay 100W COB LEDs, which is similar to the ones used in cheap ebay flood light. After comparing it with a high quality LEDs (Cree CXA3070) and doing some calculation, I decided that it is not worth saving the initial cost. In a long run, you'll be paying more money to the electricity company than going with a well designed LED fixture.

But if you are tight with your initial budget, it does grow plants (probably as well as florescent lights can). I've been running the 2x ebay COB LEDs (the ones in the linked thread) for about 8 months (I know that it is not smart to keep using this, but I was curious to see the durability of these), and orchids grow/flower ok. So you could give it a try.

[Tschimm]

Thank you for the answer naoki.
It's not a cheap one. It would cost 180$
The fancy blue and red growlights would cost easily twice as much for the same output though.

And its waterproof. No worries with misting and watering.

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[naoki]

Is this the one you are considering?:

LED Fluter, LED Strahler 100 Watt = 8500 Lumen, IP65, 6000K, 50.000h, weiss

The appearance looks identical to the common ebay flood lights, e.g.:
10W 20W 30W 50W 100W LED Flood Light Outdoor Landscape Lamp IP65 Waterproof | eBay
But it's possible that they use different parts. I looked at the site with google translate, but it doesn't mention what kind of LEDs they are using. You could ask them (and also actual energy consumption). The modern, efficient COB LEDs which I know have a round emitter area (like Cree and Bridelux), but there may be other good ones, which I don't know, with a square emitter area.

With that much of budget, if you are not stuck with white light, Hans Panel seems to use quality components with a design toward high efficiency: Ledgrow LED panel 65 w

180-200 Euro for 65-80W. This seems to be a pretty good deal for people who doesn't want to do DIY in Europe. You might think that it has lower wattage, but you'll be probably getting similar PAR (if the flood light is using good LEDs) or more PAR (if it is using the Chinese LEDs).

Waterproof is nice, but do you really need that feature?

[ALToronto]

$180 for this light seems like a rip-off. Tschimm, you're not buying this directly from China, are you? I'm sure there are lots of retailers in North America and Europe who buy from China and mark up by 900% or so.

Check out AliExpress.com - it's Alibaba's consumer site, where you can buy small quantities. Much less risky than ebay, IMO, unless you're an expert like Naoki and can ask all the right questions.

When I search for LED's, I use keywords like CREE and Bridgelux, and this cuts out the crap. Only problem - you have to search separately for drivers, but I think it's the same way everywhere.

[Tschimm]

Thank you very much for the answers !
I'll keep you updated if I will give a try to one or another

[calvin_orchidL]

The efficiency of T5HO tubes is around 92 lumens per watt. 100 watts for a measly 8500 lumens (85/watt) seems like really crappy efficiency.

Naoki - what kind of outputs are you getting with the 100W cobs?

[naoki]

Originally Posted by calvin_orchidL

The efficiency of T5HO tubes is around 92 lumens per watt. 100 watts for a measly 8500 lumens (85/watt) seems like really crappy efficiency.

Naoki - what kind of outputs are you getting with the 100W cobs?

Calvin, I didn't notice your post until now. Sorry.

My measurement of 100W eBay COB vs Cree CXA3070 is in this thread. (skip to message #18). I don't have the ability (time) to calculate the total output (micro moles/s or total lumen). But if we assume the beam spread pattern is similar, Cree CXA3070 gives about 60% more light (plant-relevant PAR) than eBay 100W COB for the same amount of energy used (watt). Bridgelux Vero 29 (pretty similar performance to your Vero 18) is pretty similar to CXA3070 (about 5% less efficient from my measurement).

Now the comparison of COB-LED vs T5HO isn't easy (point source vs linear source).

2' 24Wx4 T5HO fixture gives 160 micormoles/m^2/s at 1-foot away, and it consumes 72.6W (most T5HO seems to use less energy than the rated watt).

CXA3070 can gives 250 micro moles/m^2/s at 1' when it is using 46.2W, 340 micro moles/m^2/s with 59W.

The measurement is taken at the middle point, 1' from the fixture. T5HO has more even coverage. But if you take the average over the area, I'm guessing 46.2W LED is probably giving similar output to 72.6W.

So the common 4' 54W T5HO x 4 setting can be replaced by 2x 50W class CXA3070 or Vero 29 to cover 4'x2' area. This seems to correspond with the plant growth (just subjective comparison), too.

This will give about 40% cheaper electricity cost. It depends on the cost of electricity, but the initial cost of replacing 54Wx4 T5HO with 2x CXA3070 (about $120-150, or $100 for 2x Vero 29) can be covered by the saving in electricity within 1-2 years.

So it appears ebay 100W COB has efficiency close to T5HO, and it is not such a great deal. But the price of these eBay COB is so cheap now, it can be better than T5HO.

[Tschimm]

Thanks naoki.
Good to have you on board

[ALToronto]

Tschimm, here is a typical light for a typical price available on Alibaba. I couldn't find any 100 W lights from the same manufacturer, but your $180 will buy quite a few of these 50 W units.

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