Watts per sq ft of UV LED?

Powertech

Powertech

Well-Known Member
So, I can't really find a good answer, and so far I have been told it only needs to be 0.1 - 0.05w per sq ft of photonic power. True the UV LED's don't put out that much, but a strip of 6 280nm and 6 310 nm from cutter puts out 250mw, or 0.25watts. so, theoretically for a 5x5 you would only need 2-4 strips, and cutter themselves say you only need 2, because theirs only need 0.05w/sq ft. Their website says 1w and 0.5w, but was told last night that is an error and will get corrected

Can I get some peoples thoughts more knowledgeable than me? I have 2 of the strips on the way, and a couple strips i have from them already have some in it, so in total in UV i will have 14x 280nm, 16x 310nm , 18x 365nm, 12x 380nm, 6x 385nm, 6x 410nm. I don't think the 365 and up helps much, but its there.....well not yet but its tested other than the strips not here
 
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Rocket Soul

Rocket Soul

Well-Known Member
You should maybe hit up @nachooo , he tried uvb leds a fair bit.

Id go for a much more spreadout thing rather than the cutter strip though, thats a lot of concentration of power. Also i hear you need some uva in the mix aswell, or the uvb easily becomes too much and yield suffers a lot.
 
nachooo

nachooo

Well-Known Member
I have used succesfully 60 mw output power of 285 nm UVB leds (seoul viosys) starting 30 minutes in veg and upping until 3,5 hours at maximun in flower. This mixed with cheap 365,385,410nm leds about a max of 30 watts of input power
Area one square meter

280nm should be more tricky to use...and you should be careful with eyes and skin...those leds light are almost invisble but very dangerous
 
Powertech

Powertech

Well-Known Member
Thanks for the responses everybody.

Rocket Soul said:
You should maybe hit up @nachooo , he tried uvb leds a fair bit.

Id go for a much more spreadout thing rather than the cutter strip though, thats a lot of concentration of power. Also i hear you need some uva in the mix aswell, or the uvb easily becomes too much and yield suffers a lot.
Click to expand...
I will have basically the full range of UV, a little gap between the B and A
 
Powertech

Powertech

Well-Known Member
nachooo said:
I have used succesfully 60 mw output power of 285 nm UVB leds (seoul viosys) starting 30 minutes in veg and upping until 3,5 hours at maximun in flower. This mixed with cheap 365,385,410nm leds about a max of 30 watts of input power
Area one square meter

280nm should be more tricky to use...and you should be careful with eyes and skin...those leds light are almost invisble but very dangerous
Click to expand...
I have them on their own driver, so I will turn them off before working on anything. I always wear eye protection in the tent. I do appreciate it!
So you used 60mw in 9sq ft, i'm going to have 500 in 21ish sq ft, might be a bit much. Guess I should ask the manufacturer, but would they work just turned down a little or do they need full power?
 
nachooo

nachooo

Well-Known Member
Powertech said:
I have them on their own driver, so I will turn them off before working on anything. I always wear eye protection in the tent. I do appreciate it!
So you used 60mw in 9sq ft, i'm going to have 500 in 21ish sq ft, might be a bit much. Guess I should ask the manufacturer, but would they work just turned down a little or do they need full power?
Click to expand...
Remember that with these short wavelenghts also need skin protection... What I did was insert some visible leds in series as a signal, so if I forget that UVB ones are running ..those leds will tell me the UVB are on. Also that signal notify me that UVB is doing its work..the UVB leds emit so little light that you dont know if they are running unless you look directly at them..something that NEVER should be done.
500 mw of output power at 280 nm is a lot for 21 square foot... You can reduce time of exposure, or you can low the amps.. If you low the power you will increase led life.
Look at the datasheet provided by the led manufacturer to find output power at different amps.. and then start with low doses until find the appropiate one for your current strain. remember that 280nm leds althought not as good as 285 nm ones for our purposes (UVR8 absorption peak is at 285), will cause more damage to the plant due to the shorter wavelenght..so dont use my 285 nm measures...maybe is too much for the plants..you will have to figure by yourself... If you cant low the amps...start with very little time exposure considering the high emission of your fixture....maybe as low of 5 minuts a day ...and increase it slowly until you start to see UVB damage..them low it a bit..but as I said..I never used 280 nm ones..only 285 ones..
 
PJ Diaz

PJ Diaz

Well-Known Member
I'm gonna go with some "bro-math" on this one, and say it's 1.5watts of LED UV/sq foot. I base this off using one 30watt HLG UV bar with one HLG 550 and the results shown. I would think 2 watts/sq foot even better, but maybe too much? Seems people run around 48watts of T5 UV in a 4x4, which is closer to 3w/sq ft.
 
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