Search results

And that's when they are perfectly clean. Besides, that's just the light lost on the reflector itself. You also need to hang the COBs with 90 degree reflectors about twice as high as bare COBs to get the same light distribution. Hanging the fixture higher also means that mor of the walls will...

Yes for best uniformity, use equal spacing between the strips (and half that spacing on each side to the reflective wall).

Ah so you're saying the example is really created/tweaked solely to somehow make sense for you alone and then "prove" your point? No, that was not the reason why I replaced it. Sure, but I value my time higher than a few bucks per year. A few hundred a year is something that could be worth my...

Sure that won't help either. Still even ad the advised hanging height they still seem to bleach the plants quite easily. Intensity isn't that high in those cases.

In absolute sense the flowering light clearly saves you the most money and that's the lowest hanging fruit to spend your time on first. The VEG light is only used for 3 weeks while the flowering light is used for 10 weeks. So the savings per grow for your example it comes down to: Veg savings...

Plants have different pigment cells which absorb different wavelengths. Also plants become less efficient when dealing with higher intensities. So it makes sense that flooding just one pigment will make it less efficient than spreading out the spectrum over all pigments. I have always had the...

Maybe on COBs (especially on high power) it matters, but nowadays people use strips more and more and they have so much contact surface already that it doesn't really matter what TIM you use (if any).

Plants are hugely inefficient anyway. Only a few percent of the light they receive ends up as an increase in solid matter. Somewhere between 2% and 8% depending on circumstances and who made the estimate) Also, plants might have their reasons not to absorb certain wavelengths. like too...

I mounted 6 COBs to an extruded aluminum strip and mounted 2 CPU coolers on top. Works great. Even with the fans off they are fine. Although temperature goes up somewhat then (ie slightly lower efficiency). Plus I like the airflow from the fans (@9V) to spread the warm air from the leds over...

Sorry to say, but that guy is an idiot and otherwise highly unreliable though. Wouldn't really accept his anecdotal evidence. There are plenty people who use high PPFD values to good effect. Tried it myself too plants exploded and tops were much bigger and more compact. You do need to get...

If you want to be able to compare to actual PPF (PAR) values then use the actual PAR range of 400-700. If it's only for your own interest then you can use either (although one wont be PAR).

I use Engauge Digitizer which produces a 1nm export. In this case the trouble is not so much the digitizing though, but if you want to calculate how much watts per type of led then you need a bit more work to normalize the data

Yes it would and it is (if correctly measured). The difference would be that a space heater will heat the air while the lights would partially first need to heat up the walls till they start heating up the air (leds more so than HPS). So the heat up rate might be somewhat different, but in the...

In the case of three closed and (sort of) insulated rooms, they would all heat up at more or less the same rate and certainly to the same stabilized temperature.

@JSheeze, And again, you are only looking at photosynthesis. You need to look at the total light to biomass efficiency. There are several other steps before and after photosynthesis, all of which decrease efficiency.

Well that's what I said, there are several ways of estimating efficiency from light to biomass. Either way it's always a very small percentage, because that matches with the increase in biomass compared to amount of light given to the plants. Even if you don't know exactly how it works, its...

That's just one of the steps and in every step there is an efficiency which is not 100%. Overall from emitted light to biomass it's only a few percent. :edit: geez it's even mentioned on that wiki page! So they go with max 4.3% for "typical" plants and max 2% for crop plants.

Sorry, this is just too depressing again. So one more post wasted on the swine. Yes you don't see heat. Are you really that dense? Try keeping a thermometer under an HPS bulb and then under led. See which one gets hotter. And yes make sure light intensity and such are the same. HPS emits a...

That's how I communicate with pretenders like prawn. It's just obnoxious how he keeps spreading his nonsense without accepting any reason or acknowledging that he's clueless. You can give people a few chances, but he just keeps doing this. It's pointless to actually try to discuss with him...

Only a small percentage of the light is actually used for photosynthesis. Depends on who you ask which estimate is used, but it's somewhere between 4% and 8%.