Gavg said:

I have 2 led lights in a 150cm by 120cm by 180cm
1 vipar 450w
1 metzi 480w
Both around the same price and both have bloom switches
So I get a free light measure app from the play store it measures lux
Vipar tens at 13000 lux
Metzi runs at 13300 lux
On bloom setting
Metzi 17000 vipar 24000
In case ant one was intrested lol

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Gavg said:

At 26 inch 200w draw each according to the manufacturer how ever it is just a play store app

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CrimsonEcho said:

I thought you couldn’t get a proper reading from leds with luxmeters especially if they are not white light emmiting leds, lux is a measurement in the spectrum of what human eye can see you can’t compare that with what a plant needs is what i read and it makes sense to me.

You need a PAR meter to calculate the effectiveness of your leds but they are very expensive.

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DGP said:

Lux and lumen readings are fine for relative intensity measurements but for more precise measurements you need a good PAR meter which there is pretty much no such thing as a "good" one. They always seem to have issues.

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CrimsonEcho said:

They are not good for leds they don’t respond to the same spectrum as the plant needs, sunlight is mostly green and lightmeters are mostly for photography and they are calibrated to sunlight or various lighting equipments but not grow lights. They will not give a correct reading in my experience, it is impossible for 2x24 w t5s to give higher light intensity than a 300 w led but it gives almost the same lux value.

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DGP said:

That is because it is not a true 300 w out of the wall lamp. That is because the Chinese blurple lighting industry lies on their specifications in a big way. I saw a blurple light specified as a 1200w light that drew 250 watts from the wall. There are two classes of LED systems: 1. Real COBs from name brand vendors, Quantum boards with name brand well specified LEDs or manufactured fixtures that use the quality COBs or Quantums and then 2. Chinese blurple crap that is often re-branded and said to be made in America. The two aren't even comparable. Also been a lighting engineer for years and for "relative" intensity measurements (of a given color temperature) a lux or lumens meter is fine. So comparing a 3500K t5 system to a 3500K LED is fine for a relative comparison at a given distance not an absolute value. The minor differences in frequency are not enough to worry about except if your concerned about proper light quality then you wouldn't use blurple or pink LED's as the sun never shines that color. Also, it has been shown that green light is a very important enabler for certain plant processes that are not directly related to photosynthesis.

Dee

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CrimsonEcho said:

That example was my own experience and i know it draws 320 from the wall cause i measured it, it is a commercial fixture from a horticultural lighting company that does research and development too and it grows very nice plants.
I am not going to go in to a debate over blurples or white lights i am just saying if you have a blue and red led then lux meters will give faulty readings.

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CrimsonEcho said:

By the way not to mislead, i don’t really remember if it was 2 or 4 t5s but even then it only makes 96 watts of t5s and it is impossible for that setup to reach the same intensity of light from a 320 w led fixture let alone the same par value as t5s emit way more green than any led fixture.

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heisenbubble said:

Those blurple LED manufactures lie out the ass about there lights.They label them like Mars does there 900 but it really isnt even close to 1000W HPS.For what that mars puls from the wall or any other blurple fixture a set of QB;s or COBS will knock its DICK off.

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