NEW TO LED, help please

macl212

Member
Have a 2x4x6 grow tent, looking to put in a 4inch fan with carbon filter, looking hard at a 400w MARS light. Will this light do the job for two plants or should I be looking at only one, or is this space just to small for a 400w light? Thanks for any and all input!!!!
 

Rahz

Well-Known Member
The space is too large for that light. To me 300 watts actual output at 120+ LPW is ideal for a 2x4. The Mars actual output is around 180 watts and probably not 120 LPW.
 

macl212

Member
Have a 2x4x6 grow tent, looking to put in a 4inch fan with carbon filter, looking hard at a 400w MARS light. Will this light do the job for two plants or should I be looking at only one, or is this space just to small for a 400w light? Thanks for any and all input!
 

macl212

Member
The space is too large for that light. To me 300 watts actual output at 120+ LPW is ideal for a 2x4. The Mars actual output is around 180 watts and probably not 120 LPW.
So you are saying I need a 300w not a 400w light? Thanks!!
 

churchhaze

Well-Known Member
The Mars actual output is around 180 watts and probably not 120 LPW.
It would be extremely difficult to find a unit so heavy in R and B that with 120lm/W of source given the low LER of R and B light. In this case I'd say lm/W is a poor way to rate a lamp. (not that Mars would have a good rating anyway)
 

Tazbud

Well-Known Member
Watts don't matter a great deal, companies say anything... you want watts in light spectrum and quality that is useful to your plants. The very best current light sources can provide this 'useful' light in as little as 30-35w sq/ft /240w (4x2') being used from the wall. Cheaper LED can prove as inefficient as HPS.
 

rory420420

Well-Known Member
Have a 2x4x6 grow tent, looking to put in a 4inch fan with carbon filter, looking hard at a 400w MARS light. Will this light do the job for two plants or should I be looking at only one, or is this space just to small for a 400w light? Thanks for any and all input!!!!
I got 2 as supplemental..I love em..they're cheap,and even if they were to suck shit,I'm glad I bought em for my own interest,and now I havecmy proof,opinion,and don't have to listen to 'what its' on the subject anymore,unless I want to entertain myself...index.jpeg
 

Tim Fox

Well-Known Member
I got 2 as supplemental..I love em..they're cheap,and even if they were to suck shit,I'm glad I bought em for my own ignterest,and now I havecmy proof,opinion,and don't have to listen to 'what its' on the subject anymore,unless I want to entertain myself...View attachment 3421173
good looking tent man, many of us started with Mars, they grow bud, shoot I am still using my mars 300, but now i have a couple of cree cobs along side, I will do a few crops with the thing
 

Tim Fox

Well-Known Member
It would be extremely difficult to find a unit so heavy in R and B that with 120lm/W of source given the low LER of R and B light. In this case I'd say lm/W is a poor way to rate a lamp. (not that Mars would have a good rating anyway)
hey this guy is interested in DIY led, can you message him,
 

rory420420

Well-Known Member
good looking tent man, many of us started with Mars, they grow bud, shoot I am still using my mars 300, but now i have a couple of cree cobs along side, I will do a few crops with the thing
There's a cob in the middle of 2x 300s in that pic..
I wouldn't run my whole outfit led,unless I was small scale like the o.p...but they are good for supplemental or the closet hobbyist,affordable,and efficient..I liked em so much I bought 2 for the middle of my big grow,just to broaden the spectrum...
Live and learn,listen and lose.
 

testiclees

Well-Known Member
Have a 2x4x6 grow tent, looking to put in a 4inch fan with carbon filter, looking hard at a 400w MARS light. Will this light do the job for two plants or should I be looking at only one, or is this space just to small for a 400w light? Thanks for any and all input!!!!
i grew some decent flowers using a mars 900w (520draw) in a 4x 2 x 6...
switched to optic vero360. i am getting much better results.
 

Rahz

Well-Known Member
So you are saying I need a 300w not a 400w light? Thanks!!
The Mars 400 uses 206 watts. About 26 are from driver inefficiency and fan power, so about 180 watts of output goes to the emitters. Just saying, you're only going to get so much from 180 watts in a 2x4. Maybe buy one and see what it can do in half the space and buy another if you like it, then you would have a 400w setup.
 

Rahz

Well-Known Member
It would be extremely difficult to find a unit so heavy in R and B that with 120lm/W of source given the low LER of R and B light. In this case I'd say lm/W is a poor way to rate a lamp. (not that Mars would have a good rating anyway)
You're right, but it would be difficult for me to come up with a more scientific comparison between them and white COB emitters. The most efficient 180 watts on the market isn't going to kill it in a 2x4. 400w HPS is an option similar in price to what mac is thinking about spending, so that's a possible option. 300w COB is a better option, but it going to run around $600-800.

What do you think about 2 of the Mars in a 2x4? Even if they weren't very efficient it would still be 360 watts and a $400 solution.
 

macl212

Member
Thank you all for the great info, growing for my own use. Helps keep the PTSD monster away, thinking about making a grow cab the same size as my tent and trying out two 400w Mars lights, need stealth. How load are LED's ? Will also be running fan with carbon filter to keep everything from smelling up the house. Once again thanks for all the great info, hope to grow some sleep meds without any visitors having any idea!!!!!!!:grin:
 

macl212

Member
Thank you all for the great info, growing for my own use. Helps keep the PTSD monster away, thinking about making a grow cab the same size as my tent and trying out two 400w Mars lights, need stealth. How load are LED's ? Will also be running fan with carbon filter to keep everything from smelling up the house. Once again thanks for all the great info, hope to grow some sleep meds without any visitors having any idea!!!!!!!:grin:
loud, not load, sorry
 

alesh

Well-Known Member
It would be extremely difficult to find a unit so heavy in R and B that with 120lm/W of source given the low LER of R and B light. In this case I'd say lm/W is a poor way to rate a lamp. (not that Mars would have a good rating anyway)
Impossible, actually. Both 450nm and 660nm LEDs have LER << 120 lm/W.
 
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