Lighting question

FullMetalJacket said:

My calculations on the 600 were as follows:

Yes 1000 W is greater than 600. But the 600 can be placed roughly 12 inches closer to the plants which.

Light output divided by ditance squared = lumens

1000 watts/3x3=9=111 lumens
600 watts/2x2=4=150 lumens"

Click to expand...

Actually 1000's can be placed within 18 inches if there air cooled as well

but I am still failing to see how your gettin that

140,000 lumens dissapated down 2 feet goes to 111 lumens..

it follows the inverse square ratio, meaning at 1 foot away from the 1000 it would be 70,000 lumens and two feet away 35,000 lumens...

not 111 lumens...

And to be honest Lumens are hogwash..
Par is for plants, lumens is for people....

Wait a tick, your thinking about the equation wrong...

Light output divided by ditance squared = lumens

Distance squared isnt the floor sapce squared, its the distance from the bulb to plant canopy squared...

1 squared = 1
2 feet away squared = 4...

so you divide 140,000 by 4 to get how many lumens will hit the surface at two feet.

jonnyk said:

Just a quick question if anyone can help.
I have a room, 7x8 ft. i have enough room for 3 lights in air cooled hoods.
I have one 400w digital ballast.
Should I buy two more 400watters? Or can I do one 400 watter, and one or two 600 watters? Can I mix them up??
Should all my lights be the same wattage to have good control of my grow room? I'd appreciate any input. Thanks!

-J

Click to expand...

hey J

Just stick to the science of things and you'll be fine...

400 watt can cover a 3x3 section optimally (i have seen 4x4 and 5x5 with 1 400 watter..)

600 watt is a 5x5

1000 watt is a 8x8

Your decision should be based on at least these things:

Money: How much you want to spend per month on elec bill when you take into account the watts for the lights plus the cooling.. the rest should be the same no matter what the lights you use.. there really isnt that much of a difference when buying the light,hood & ballast to make that big of a diference.

Space requirements: LIke i explained above.... your 7x8... hell 2 400 watts would work... but if you dont care (and your breaker can handle) about the monthly changes of 200 watts then i would put your 400 and 1 600

thats about it for that.... good luck J

Thanks a lot guys for all your help. I think Im gonna go with the 600. 1000 is a lot. And 400 just wont cut it. All that math hurts my head... Too blazed right now. But from what it seems, I need somehting to vent out the air cooled hoods. And another to suck the hot air out of the room?? I am blessed with a room, with vents that go right up to the roof. They already seem to suck air without any fans. The only thing that seems hard, is if i need to suck air out of the room, and the hoods, thats two vents, plus another to blow fresh air in the room.
Where the hell am i gonan get all those sources?? Can i split one hole into two, and have to ducts connected to it??

-J