Mars-Hydro LED Grow Light Discussion

:welcome: icelikewinip, it's not an issue. The fan will work when veg switch is on. During veg, just turn on veg. During flower, you need turn on both switches. :circle-of-love:
sorry if this has been covered, but im curious why my 144x5 reflector's fan shuts off when just the bloom button is pushed? anyone else had this issue?
 
:welcome: icelikewinip, it's not an issue. The fan will work when veg switch is on. During veg, just turn on veg. During flower, you need turn on both switches. :circle-of-love:

but the red spectrum is significantly less when the veg is on with bloom. if both buttons are on, its very blue instead of red. is it not meant to work with just bloom? it seems like a manufacturing issue as the fan should work properly in all instances :S
I don't want both on, just bloom, and it doesn't work properly
 
:thumb: plants use a different part of the light spectrum than what human eyes are mostly sensitive to. PAR is indeed supposed to be the preferable measurement, but we don't test PAR now. We have ever tested our 96x3w led grow light and found that if we use lower beam angle, higher umol. Since LED grow light has already used the light spectrum required for the plants, you can take the ture watt as a reference. :Namaste:

Yes of course, just 2000W sounds high to me, at least for "a bunch" of personal plants.

By the way, this just as a side-note, I think Wattage, whether it's "wall wattage" or whatever Wattage is a totally meaningless figure. What does "50W per sq ft" mean seeing that different types of lights (LEDs, HPS, CFL etc) have a totally different light output per watt. Simple example, my living room LEDs put out as much, if not more, light at 4.5W as my Halogen lights which use 10x more, wattage means NOTHING.

You may even know that not even Lumens or Lux mean anything, I understand that the only useable number here is PAR, the light plants actually use. This is why I don't understand why people are looking at Watts, it just doesn't mean a thing.

Edit: Ok you say "50W per sq ft" for LED, so it's more specific...

:circle-of-love:Dark, I have to say, you know our products more than me. :bravo:
ok then ....

you will get a very nice PAR(or light power usable for plants) for growing/flowering marijuana with 45-55W true watts per square foot with mars hydro products (others leds maybe different) ..... whatever the way you like, the important is to have enought light to power your plants ;-)

(old model series is better to use 60W &+ per square foot)
(all new model with cree leds will be very less, maybe 35-40W per square foot ... maybe)
 
Hi ice, when both of swithces are on, it's full spectrum with Red, Blue, White and IR.
the red spectrum will be not less. It seems not so red because of mixture of other colors. In fact, the red spectrum will be more, because our veg spectrum also has red diodes. Your plant will grow well under full spectrum :circle-of-love:
Hmm... the fan and veg section share the same driver. All our Reflector designs like this. :Namaste:
but the red spectrum is significantly less when the veg is on with bloom. if both buttons are on, its very blue instead of red. is it not meant to work with just bloom? it seems like a manufacturing issue as the fan should work properly in all instances :S
I don't want both on, just bloom, and it doesn't work properly
 
:circle-of-love:
yep, website is down ... maybe updates

definitivly go with 144X5 for your 6 square foots area ... 96X3 is clearly not enought.

try to use at least 50w true watt per square foot .... so 300W for your area ..... 144X5 consume very near 300W true watts so you are good (not sure exactly but little more than 300w i think)

:thumb:
my 144x5 pulls 315 watts, jumps around a watt or 2. i actually have a vid of the watt test on this forum. ill re-post it if ppl are interested
 
:thumb:Different kind of light sources have various ways to define their wattage. Even for the same kind, the measurement will be different from manufacturers. More research remains to be done before jumping to a comparision result. :Namaste:
There is a formula for each of the different types and it is all just guidelines and will vary with application and what the grower is expecting as for wall or input wattage it is a constant measurement not a obscure number thrown out by manufactures. It was common to see a figure of 1000 watts on a panel when the draw was only 200 watts so the light was at best 400 watts but sold better as a 1000 to the public that didn't know better that is why it is nice to see the Mars Hydro lights show both the power draw and efficiency figures of their light no special math to hide the truth. Watts do mean something you just have to understand how the light is produced halogen lights heat a element in a gas LED gets a small flash as the electrons pass from one pole to the other(simple terms ) therefor using less power for the same light.
 
:thumb:it's helpful. :Namaste:
Sara,

I think you might like to know. Within a grow space that is 53.34cm square and is 1.6m tall. With my 48x3w reflector light tilted to about 45 degrees I am still getting a 10,240 lux reading from the reflected light at soil level.
 
I know there is countless information on this on the web, but nothing definitive.

What is the recommended hanging distance above plants for the 60x5W 300W "old model"?
Is it 18" (45cm) to 24" (61cm) ?

And...What is the recommended distance for sprouting seedlings?
Right now I have it at approx. 18", should I lower it for seedlings?
 
How to Determine the Correct Mars-Hydro LED Grow Light to Purchase for Your Specific Gardening Needs


Case Study - Grow Space Size is 4' wide x 4' Long x 6'6" High

How do I determine the square footage of my grow area?
Measure the floor space that you'll be looking to illuminate with your future LED light and hopefully fill with sticky buds someday.
Multiply the length times the width and this will give you the square footage. Since the grow space indicated in our case study is 4' long by 4' wide we would multiply 4 times 4 which equals to 16 square foot of grow space.
Length (4') x Width (4') = Total Square Feet (16')

How many actual watts of power will it take to for me to grow decent or high quality meds?
You should be able to get decent results with as little as 20-25 actual watts of power per square foot of grow space with the light set about 18" above the canopy during bloom.

If you want to step up your game, increase yields, and grow really thick and dense nuggets with higher resin content then you'll probably want to be somewhere around 30 to 50 watts of actual power per square foot during bloom with the lights set approximately 18" above the canopy.

In general, the more power per square foot, the better the quality of the finished product.....within reason of course.
Yes, there is a such thing as too much light. Anything over 50 actual watts per square foot would likely require CO2 supplementation and heat issues would need to be adequately addressed.

For the same light, Mars-Hydro gives two different numbers for actual watts. How do I determine how many actual watts to use for my calculations?
Visit the Mars-Hydro website and select the light you are interested in evaluating. For the purpose of this exercise we'll evaluate the Mars2 700 Watt light.
Now check the following:
How many actual watts does the light draw? The website list 300-380 watts power draw. This means the light will draw approximately 300 watts if using a 220volt/50Hz electrical grid or 380 watts if using 110volt/60Hz electrical grid. For the purpose of this exercise we will use 380 watts as our wattage draw number.

What is the effective illumination area at 18"?
Note that the effective illumination area is shown as 3.5'x3.5' @ 24".
But remember, you'll usually want to have your lights set at 18" or less during bloom not 24". So 3.5'x3.5' (12.25 sq/ft) is not the number that you'll want to be using to evaluate this light if you want to use it for flowing.

Scroll down a bit on the web page and on the lower right side of the web page you'll see this graph.
vertical-illumination-80x51.jpg


This graph illustrates how the light intensity increases and the effective illumination area decreases as the light gets nearer to the plant canopy. This is why you'll want to set your light as low as possible during flower without burning your plants.

Per the graph you'll find that the Mars2 700 watt light delivers about 9880 LUX at 50cm or 19.6" This is the approximate distance that you'd want this light set during bloom.
So effective illumination for this light when used for bloom will be less than 3.5'x3.5' as stated in the specs. The actual effective illumination area when using this light for flowing would be about 3'x3' or 9 square foot.

So....now that we know how much space we need to illuminate (16 sq/ft), we know the actual wattage the light puts out (380 watts), and we've determined the approximate effective illumination area for this light when used for flowering (9 sq/ft)....what now?

Take the actual wall watts that the light draws (380 watts) and divide this number by the effective illumination at 18" (9 sq/ft). 380 watts divided by 9 sq/ft = 42 watts per sq/ft so this means that the Mars2 700 watt light would deliver approximately 42 watts of actual power per square foot when set approximately 18" above the plant canopy.

42 watts per square foot will grow some really fine medicine. But if you recall, our grow space is 16 sq/ft. In order for this light to illuminate 16 square feet we would need to raise it to about 32" or more above the plant canopy. Now moving the light further from the canopy will light up more area but it will also result in less light intensity at the plant canopy or less wattage per square foot.
380 watts divided by 16 square foot = 23.75 watts per square foot. Can you still grow pot with 23.75 watts per sq/ft. Sure you can, but yields and bud density will not be as good as they would be with a larger/more powerful light.

So now let's go ahead and take a look at the Mars2 1600 Watt light.
This light has an actual power draw of 780 watts when plugged into a 110 volt grid.
Lets assume that the effective illumination area at 18" above the canopy would be approximately 4.5'x4.5' or 6" less in all directions than what is stated on the website for a light being set at 24". 4.5'x4.5'=20.25 sq/ft
So we would take the actual wattage (780) and divide this by the effective illumination area at 18" above the canopy (20.25 sq/ft) to determine the watts per square foot.
780 watts divided by 20.25 = 38.5 watts per square foot.
At 38.5 watts per square foot this would allow you to grow top quality buds with large yields.

But wait, our grow space is only 16 sq/ft remember. So if we set this light at 18" above the canopy we still come up with the same answer of 38.5 watts per sq/ft but we now have light spilling over onto the walls since the effective illumination area is larger than our space. This will result in some of the light being reflected back onto the plants so the actual light being delivered to the plant will actually be a tad greater than 38.5 watts per sq/ft. Don't ask me how to calculate reflected light unless you want a B.S. answer. :)

On the other hand, if your plants can handle the light being lowered to 12" above the canopy which they often will you'll end up with a perfect fit in regards to illumination area of the light versus grow space size. In addition your watts per square foot will increase to 48.75 watts per square foot since the the light is closer to the plant canopy and the effective illumination would now be reduced from 20sq/ft to 16sq/ft, the exact size of our grow space.
780 watts divided by 16 square foot illumination area (reduced illumination area caused by dropping the light to 12" above the canopy) = 48.75 watts.

This light would be about as large and powerful as you'd want to go for this size grow space. Anything more powerful than the Mars2 1600 for a 16 sq/ft grow space would likely be overkill and only result in wasted electricity and heat issues.
Assuming that your gardening skills are up to par, you'll be able to grow top quality buds with this lamp and may be a perfect fit for your needs. However, if you are on a tight budget or trying to minimize heat or electrical usage you could probably go with a lesser light and still grow high quality produce.

Now lets take a look at the Mars2 1200 watt light.
520 actual watts using 120 volt power supply.
Effective illumination area for flowing with this light would be approximately 4'x4' or 16 sq/ft.

520 watts divided by 16 sq/ft = 32.5 watts per square foot.
This light would be a nice fit for anyone looking to grow good quality medicine with the expectation of ideal yields in a 16 square foot grow space. This light is not too powerful but not too weak either. This light would probably be the "sweet spot" for most hobby growers.

Should I go with 5 watt or 3 watt diodes?
The 5 watt diodes should allow for deeper penetration into the plant canopy resulting in less "larf" or airy buds below the main canopy. As a trade off, the 5 watt diodes may result in more heat compared to 3 watt diodes.
Note that I've seen some really fine crops grown with the 3 watt Reflector Series lights.
3 watt or 5 watt would be based on the personal preference of the end user.

For larger areas should I go with a single large panel or multiple medium to small lights?
In general it would be best to use multiple lights instead of a single light panel. The reason for this is improved lighting coverage. With all or most LED lights the light intensity at the canopy is greatest near the center area of the effective illumination area. In other words if the effective illumination area of the light is 9 square feet, the middle area of this 9 square feet (about 4 sq/ft or so) will be much more brightly lit up with light intensity diminishing rapidly as you move further away from center. This results in better growth / thicker denser buds which are located nearer to the center if the light.
Using multiple lights allows you to better distribute the intense light in more areas of the grow space instead of having all of the higher intensity light concentrated in only one area while the outer edges never receive intense light.
It also allows you to minimize low light areas by having the ability to move individual lights around as needed in order to minimize light gaps or dark/shaded areas.
I hope this makes sense to everyone.

Anyways, my work is done here and I do hope this helps those that may be new to LED lighting technology to properly evaluate all of the different Mars-Hydro LED light offerings and determine which light would best suit your needs and available grow space.
Hopefully this will also result in less Q&A sessions for Sara. :blushsmile:

Sara,
Please feel free to chime in and correct me if I've stated anything that may be incorrect or misleading.

Happy gardening friends! :rollit:

:peace:
 
wow bro you should be compensated for that work
unclecannabis for president 2016!!
for real though highly pertinent and informational
thanks kind sir

i have been away quite a while and i think i am seeing that all reflector panels are now 5W? is this true?
 
wow bro you should be compensated for that work
unclecannabis for president 2016!!
for real though highly pertinent and informational
thanks kind sir

i have been away quite a while and i think i am seeing that all reflector panels are now 5W? is this true?

Wow! Thanks for the kind words YuYo.
Just a few short months ago I decided to take the LED plunge but for a while there I was thoroughly confused about which light I should go with. It took a while to sort through things but at some point things began to all make sense to me.
I thought I'd try to help out others who are in the same boat that I was in back then by attempting to explain things in layman's terms and hopefully flatten out the learning curve a bit for others.

I do know that are are some still available with the 3 watt diodes but I'm not sure which ones. Sara would the person to answer your question about the change from 3 watt to 5 watt with the Reflector Series.
 
flexy, our recommendated height is 18"~24". :circle-of-love: for small babies, take care of the distance, it's better not to go any lower.:circle-of-love:
I know there is countless information on this on the web, but nothing definitive.

What is the recommended hanging distance above plants for the 60x5W 300W "old model"?
Is it 18" (45cm) to 24" (61cm) ?

And...What is the recommended distance for sprouting seedlings?
Right now I have it at approx. 18", should I lower it for seedlings?
 
flexy, our recommendated height is 18"~24". :circle-of-love: small baby, no less than 24inches, when they grow a bit bigger, 18inches. flowering stage, you can put 12~18inches, depends on your need.:Namaste:
I know there is countless information on this on the web, but nothing definitive.

What is the recommended hanging distance above plants for the 60x5W 300W "old model"?
Is it 18" (45cm) to 24" (61cm) ?

And...What is the recommended distance for sprouting seedlings?
Right now I have it at approx. 18", should I lower it for seedlings?
 
:bravo:you guys are the reason why I love 420 more than other forums. People here are very generous and friendly.:circle-of-love: I feel be loved here and feel the meaning in my work. :Namaste: I literally share the instruction with my colleagues. Thank you, UncleCannabis.:thanks:
How to Determine the Correct Mars-Hydro LED Grow Light to Purchase for Your Specific Gardening Needs


Case Study - Grow Space Size is 4' wide x 4' Long x 6'6" High

How do I determine the square footage of my grow area?
Measure the floor space that you'll be looking to illuminate with your future LED light and hopefully fill with sticky buds someday.
Multiply the length times the width and this will give you the square footage. Since the grow space indicated in our case study is 4' long by 4' wide we would multiply 4 times 4 which equals to 16 square foot of grow space.
Length (4') x Width (4') = Total Square Feet (16')

How many actual watts of power will it take to for me to grow decent or high quality meds?
You should be able to get decent results with as little as 20-25 actual watts of power per square foot of grow space with the light set about 18" above the canopy during bloom.

If you want to step up your game, increase yields, and grow really thick and dense nuggets with higher resin content then you'll probably want to be somewhere around 30 to 50 watts of actual power per square foot during bloom with the lights set approximately 18" above the canopy.

In general, the more power per square foot, the better the quality of the finished product.....within reason of course.
Yes, there is a such thing as too much light. Anything over 50 actual watts per square foot would likely require CO2 supplementation and heat issues would need to be adequately addressed.

For the same light, Mars-Hydro gives two different numbers for actual watts. How do I determine how many actual watts to use for my calculations?
Visit the Mars-Hydro website and select the light you are interested in evaluating. For the purpose of this exercise we'll evaluate the Mars2 700 Watt light.
Now check the following:
How many actual watts does the light draw? The website list 300-380 watts power draw. This means the light will draw approximately 300 watts if using a 220volt/50Hz electrical grid or 380 watts if using 110volt/60Hz electrical grid. For the purpose of this exercise we will use 380 watts as our wattage draw number.

What is the effective illumination area at 18"?
Note that the effective illumination area is shown as 3.5'x3.5' @ 24".
But remember, you'll usually want to have your lights set at 18" or less during bloom not 24". So 3.5'x3.5' (12.25 sq/ft) is not the number that you'll want to be using to evaluate this light if you want to use it for flowing.

Scroll down a bit on the web page and on the lower right side of the web page you'll see this graph.
vertical-illumination-80x51.jpg


This graph illustrates how the light intensity increases and the effective illumination area decreases as the light gets nearer to the plant canopy. This is why you'll want to set your light as low as possible during flower without burning your plants.

Per the graph you'll find that the Mars2 700 watt light delivers about 9880 LUX at 50cm or 19.6" This is the approximate distance that you'd want this light set during bloom.
So effective illumination for this light when used for bloom will be less than 3.5'x3.5' as stated in the specs. The actual effective illumination area when using this light for flowing would be about 3'x3' or 9 square foot.

So....now that we know how much space we need to illuminate (16 sq/ft), we know the actual wattage the light puts out (380 watts), and we've determined the approximate effective illumination area for this light when used for flowering (9 sq/ft)....what now?

Take the actual wall watts that the light draws (380 watts) and divide this number by the effective illumination at 18" (9 sq/ft). 380 watts divided by 9 sq/ft = 42 watts per sq/ft so this means that the Mars2 700 watt light would deliver approximately 42 watts of actual power per square foot when set approximately 18" above the plant canopy.

42 watts per square foot will grow some really fine medicine. But if you recall, our grow space is 16 sq/ft. In order for this light to illuminate 16 square feet we would need to raise it to about 32" or more above the plant canopy. Now moving the light further from the canopy will light up more area but it will also result in less light intensity at the plant canopy or less wattage per square foot.
380 watts divided by 16 square foot = 23.75 watts per square foot. Can you still grow pot with 23.75 watts per sq/ft. Sure you can, but yields and bud density will not be as good as they would be with a larger/more powerful light.

So now let's go ahead and take a look at the Mars2 1600 Watt light.
This light has an actual power draw of 780 watts when plugged into a 110 volt grid.
Lets assume that the effective illumination area at 18" above the canopy would be approximately 4.5'x4.5' or 6" less in all directions than what is stated on the website for a light being set at 24". 4.5'x4.5'=20.25 sq/ft
So we would take the actual wattage (780) and divide this by the effective illumination area at 18" above the canopy (20.25 sq/ft) to determine the watts per square foot.
780 watts divided by 20.25 = 38.5 watts per square foot.
At 38.5 watts per square foot this would allow you to grow top quality buds with large yields.

But wait, our grow space is only 16 sq/ft remember. So if we set this light at 18" above the canopy we still come up with the same answer of 38.5 watts per sq/ft but we now have light spilling over onto the walls since the effective illumination area is larger than our space. This will result in some of the light being reflected back onto the plants so the actual light being delivered to the plant will actually be a tad greater than 38.5 watts per sq/ft. Don't ask me how to calculate reflected light unless you want a B.S. answer. :)

On the other hand, if your plants can handle the light being lowered to 12" above the canopy which they often will you'll end up with a perfect fit in regards to illumination area of the light versus grow space size. In addition your watts per square foot will increase to 48.75 watts per square foot since the the light is closer to the plant canopy and the effective illumination would now be reduced from 20sq/ft to 16sq/ft, the exact size of our grow space.
780 watts divided by 16 square foot illumination area (reduced illumination area caused by dropping the light to 12" above the canopy) = 48.75 watts.

This light would be about as large and powerful as you'd want to go for this size grow space. Anything more powerful than the Mars2 1600 for a 16 sq/ft grow space would likely be overkill and only result in wasted electricity and heat issues.
Assuming that your gardening skills are up to par, you'll be able to grow top quality buds with this lamp and may be a perfect fit for your needs. However, if you are on a tight budget or trying to minimize heat or electrical usage you could probably go with a lesser light and still grow high quality produce.

Now lets take a look at the Mars2 1200 watt light.
520 actual watts using 120 volt power supply.
Effective illumination area for flowing with this light would be approximately 4'x4' or 16 sq/ft.

520 watts divided by 16 sq/ft = 32.5 watts per square foot.
This light would be a nice fit for anyone looking to grow good quality medicine with the expectation of ideal yields in a 16 square foot grow space. This light is not too powerful but not too weak either. This light would probably be the "sweet spot" for most hobby growers.

Should I go with 5 watt or 3 watt diodes?
The 5 watt diodes should allow for deeper penetration into the plant canopy resulting in less "larf" or airy buds below the main canopy. As a trade off, the 5 watt diodes may result in more heat compared to 3 watt diodes.
Note that I've seen some really fine crops grown with the 3 watt Reflector Series lights.
3 watt or 5 watt would be based on the personal preference of the end user.

For larger areas should I go with a single large panel or multiple medium to small lights?
In general it would be best to use multiple lights instead of a single light panel. The reason for this is improved lighting coverage. With all or most LED lights the light intensity at the canopy is greatest near the center area of the effective illumination area. In other words if the effective illumination area of the light is 9 square feet, the middle area of this 9 square feet (about 4 sq/ft or so) will be much more brightly lit up with light intensity diminishing rapidly as you move further away from center. This results in better growth / thicker denser buds which are located nearer to the center if the light.
Using multiple lights allows you to better distribute the intense light in more areas of the grow space instead of having all of the higher intensity light concentrated in only one area while the outer edges never receive intense light.
It also allows you to minimize low light areas by having the ability to move individual lights around as needed in order to minimize light gaps or dark/shaded areas.
I hope this makes sense to everyone.

Anyways, my work is done here and I do hope this helps those that may be new to LED lighting technology to properly evaluate all of the different Mars-Hydro LED light offerings and determine which light would best suit your needs and available grow space.
Hopefully this will also result in less Q&A sessions for Sara. :blushsmile:

Sara,
Please feel free to chime in and correct me if I've stated anything that may be incorrect or misleading.

Happy gardening friends! :rollit:

:peace:
 
:circle-of-love: welcome back yuyo, in US, all Reflector series has been updated to 5w leds except Reflector 48x3w. In Germany warehouse, all Reflector are with 5w leds. Moreover, the price has not been increased yet, the same as before. :cheer:
wow bro you should be compensated for that work
unclecannabis for president 2016!!
for real though highly pertinent and informational
thanks kind sir

i have been away quite a while and i think i am seeing that all reflector panels are now 5W? is this true?


:Namaste:every teacher has ever been a student. Now, you are qualified to be a good teacher.:goodjob:
Wow! Thanks for the kind words YuYo.
Just a few short months ago I decided to take the LED plunge but for a while there I was thoroughly confused about which light I should go with. It took a while to sort through things but at some point things began to all make sense to me.
I thought I'd try to help out others who are in the same boat that I was in back then by attempting to explain things in layman's terms and hopefully flatten out the learning curve a bit for others.

I do know that are are some still available with the 3 watt diodes but I'm not sure which ones. Sara would the person to answer your question about the change from 3 watt to 5 watt with the Reflector Series.
 
nice post uncle!!! wow!


How to Determine the Correct Mars-Hydro LED Grow Light to Purchase for Your Specific Gardening Needs


Case Study - Grow Space Size is 4' wide x 4' Long x 6'6" High

How do I determine the square footage of my grow area?
Measure the floor space that you'll be looking to illuminate with your future LED light and hopefully fill with sticky buds someday.
Multiply the length times the width and this will give you the square footage. Since the grow space indicated in our case study is 4' long by 4' wide we would multiply 4 times 4 which equals to 16 square foot of grow space.
Length (4') x Width (4') = Total Square Feet (16')

How many actual watts of power will it take to for me to grow decent or high quality meds?
You should be able to get decent results with as little as 20-25 actual watts of power per square foot of grow space with the light set about 18" above the canopy during bloom.

If you want to step up your game, increase yields, and grow really thick and dense nuggets with higher resin content then you'll probably want to be somewhere around 30 to 50 watts of actual power per square foot during bloom with the lights set approximately 18" above the canopy.

In general, the more power per square foot, the better the quality of the finished product.....within reason of course.
Yes, there is a such thing as too much light. Anything over 50 actual watts per square foot would likely require CO2 supplementation and heat issues would need to be adequately addressed.

For the same light, Mars-Hydro gives two different numbers for actual watts. How do I determine how many actual watts to use for my calculations?
Visit the Mars-Hydro website and select the light you are interested in evaluating. For the purpose of this exercise we'll evaluate the Mars2 700 Watt light.
Now check the following:
How many actual watts does the light draw? The website list 300-380 watts power draw. This means the light will draw approximately 300 watts if using a 220volt/50Hz electrical grid or 380 watts if using 110volt/60Hz electrical grid. For the purpose of this exercise we will use 380 watts as our wattage draw number.

What is the effective illumination area at 18"?
Note that the effective illumination area is shown as 3.5'x3.5' @ 24".
But remember, you'll usually want to have your lights set at 18" or less during bloom not 24". So 3.5'x3.5' (12.25 sq/ft) is not the number that you'll want to be using to evaluate this light if you want to use it for flowing.

Scroll down a bit on the web page and on the lower right side of the web page you'll see this graph.
vertical-illumination-80x51.jpg


This graph illustrates how the light intensity increases and the effective illumination area decreases as the light gets nearer to the plant canopy. This is why you'll want to set your light as low as possible during flower without burning your plants.

Per the graph you'll find that the Mars2 700 watt light delivers about 9880 LUX at 50cm or 19.6" This is the approximate distance that you'd want this light set during bloom.
So effective illumination for this light when used for bloom will be less than 3.5'x3.5' as stated in the specs. The actual effective illumination area when using this light for flowing would be about 3'x3' or 9 square foot.

So....now that we know how much space we need to illuminate (16 sq/ft), we know the actual wattage the light puts out (380 watts), and we've determined the approximate effective illumination area for this light when used for flowering (9 sq/ft)....what now?

Take the actual wall watts that the light draws (380 watts) and divide this number by the effective illumination at 18" (9 sq/ft). 380 watts divided by 9 sq/ft = 42 watts per sq/ft so this means that the Mars2 700 watt light would deliver approximately 42 watts of actual power per square foot when set approximately 18" above the plant canopy.

42 watts per square foot will grow some really fine medicine. But if you recall, our grow space is 16 sq/ft. In order for this light to illuminate 16 square feet we would need to raise it to about 32" or more above the plant canopy. Now moving the light further from the canopy will light up more area but it will also result in less light intensity at the plant canopy or less wattage per square foot.
380 watts divided by 16 square foot = 23.75 watts per square foot. Can you still grow pot with 23.75 watts per sq/ft. Sure you can, but yields and bud density will not be as good as they would be with a larger/more powerful light.

So now let's go ahead and take a look at the Mars2 1600 Watt light.
This light has an actual power draw of 780 watts when plugged into a 110 volt grid.
Lets assume that the effective illumination area at 18" above the canopy would be approximately 4.5'x4.5' or 6" less in all directions than what is stated on the website for a light being set at 24". 4.5'x4.5'=20.25 sq/ft
So we would take the actual wattage (780) and divide this by the effective illumination area at 18" above the canopy (20.25 sq/ft) to determine the watts per square foot.
780 watts divided by 20.25 = 38.5 watts per square foot.
At 38.5 watts per square foot this would allow you to grow top quality buds with large yields.

But wait, our grow space is only 16 sq/ft remember. So if we set this light at 18" above the canopy we still come up with the same answer of 38.5 watts per sq/ft but we now have light spilling over onto the walls since the effective illumination area is larger than our space. This will result in some of the light being reflected back onto the plants so the actual light being delivered to the plant will actually be a tad greater than 38.5 watts per sq/ft. Don't ask me how to calculate reflected light unless you want a B.S. answer. :)

On the other hand, if your plants can handle the light being lowered to 12" above the canopy which they often will you'll end up with a perfect fit in regards to illumination area of the light versus grow space size. In addition your watts per square foot will increase to 48.75 watts per square foot since the the light is closer to the plant canopy and the effective illumination would now be reduced from 20sq/ft to 16sq/ft, the exact size of our grow space.
780 watts divided by 16 square foot illumination area (reduced illumination area caused by dropping the light to 12" above the canopy) = 48.75 watts.

This light would be about as large and powerful as you'd want to go for this size grow space. Anything more powerful than the Mars2 1600 for a 16 sq/ft grow space would likely be overkill and only result in wasted electricity and heat issues.
Assuming that your gardening skills are up to par, you'll be able to grow top quality buds with this lamp and may be a perfect fit for your needs. However, if you are on a tight budget or trying to minimize heat or electrical usage you could probably go with a lesser light and still grow high quality produce.

Now lets take a look at the Mars2 1200 watt light.
520 actual watts using 120 volt power supply.
Effective illumination area for flowing with this light would be approximately 4'x4' or 16 sq/ft.

520 watts divided by 16 sq/ft = 32.5 watts per square foot.
This light would be a nice fit for anyone looking to grow good quality medicine with the expectation of ideal yields in a 16 square foot grow space. This light is not too powerful but not too weak either. This light would probably be the "sweet spot" for most hobby growers.

Should I go with 5 watt or 3 watt diodes?
The 5 watt diodes should allow for deeper penetration into the plant canopy resulting in less "larf" or airy buds below the main canopy. As a trade off, the 5 watt diodes may result in more heat compared to 3 watt diodes.
Note that I've seen some really fine crops grown with the 3 watt Reflector Series lights.
3 watt or 5 watt would be based on the personal preference of the end user.

For larger areas should I go with a single large panel or multiple medium to small lights?
In general it would be best to use multiple lights instead of a single light panel. The reason for this is improved lighting coverage. With all or most LED lights the light intensity at the canopy is greatest near the center area of the effective illumination area. In other words if the effective illumination area of the light is 9 square feet, the middle area of this 9 square feet (about 4 sq/ft or so) will be much more brightly lit up with light intensity diminishing rapidly as you move further away from center. This results in better growth / thicker denser buds which are located nearer to the center if the light.
Using multiple lights allows you to better distribute the intense light in more areas of the grow space instead of having all of the higher intensity light concentrated in only one area while the outer edges never receive intense light.
It also allows you to minimize low light areas by having the ability to move individual lights around as needed in order to minimize light gaps or dark/shaded areas.
I hope this makes sense to everyone.

Anyways, my work is done here and I do hope this helps those that may be new to LED lighting technology to properly evaluate all of the different Mars-Hydro LED light offerings and determine which light would best suit your needs and available grow space.
Hopefully this will also result in less Q&A sessions for Sara. :blushsmile:

Sara,
Please feel free to chime in and correct me if I've stated anything that may be incorrect or misleading.

Happy gardening friends! :rollit:

:peace:
 
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