400 watt HID in small space

Discussion in 'Growing Marijuana Indoors' started by badwolf4, Feb 21, 2009.

  1. I have a 400 watt HPS cool tube light that I'm considering using in my 21" deep x 54" wide x 65" high space. I figured out that makes the wattage out to be about 50 watts per square inch. Is that overkill?

    Also, I've heard that HID has to be a ways from the tops of the plants, and since my space is so small, I'm thinking that I might not be able to use this light there. Would it be best to go with dwarf plants?

    At first I thought about 4' shop lights, but that might not be powerful enough to give me the yield I'd like.

    Thanks for any feedback.
  2. with the cool tube you should be fine, when the babies are young keep the light up high, but after they are established(8inches or more) then slowy drop the light a bit each day.....true test is. hold your hand over your tops, if it's uncomfortably HOT for your hand, if is for the plant s too.. should be able to keep your hand there and NOT burn....
  3. Thanks Mr T.
  4. hi everyone.... this is my first post, so ill take the chance to say hi to everyone on the forum. im slanaxe, typin' outta italy... nice to meet ya all!!

    you'll have no problems running a 400W in such a space, but as our 'collegue' pointed out, you'll definitely need a cooltube.
    I run a 400W HPS in a closet thats about 1.5m X 0.70m X 2m (sorry guys.... i just dont unerstand inches and feet :( ) and i had to resort to passive intakes for ventilation beacuse with any active kind of vents (before i was running 2 PC fans) my temps would drop too low. Mind you, my closet is in a tool shed outside the house with no heating and very little insulation, so the temps are naturally low. but even in a heated environment im sure youll have no problems running a similar set up.
    the only piece of advice that i can give you is to keep the lamp's ballast outside of the grow room, as it produces quite a lot of heat (it's also the safest choice).
    thats all... good luck with your project, mate!
  5. You have about 50 watts per sq foot, not per sq inch. That's sufficient but not great. But only if you are wanting to use the entirety of that 54" length. Your cab is relatively long and narrow compared to the footprint of the light, use only about 36-40" of that width and you'll be fine.
  6. I have run a 600w and now 400w in a smaller space. You just need to get your ventilation tuned in.
  7. Oh yeah I meant square foot. 50 per inch would be like a laser beam!

    I'll definitely run the ballast remote out of the cab, and I'll use 6" duct (the cool tube is 6") to go from the cab to my attic and there will be my fan so it will be quieter.

    Thanks for the advice all!
  8. #8 badwolf4, Feb 23, 2009
    Last edited by a moderator: Feb 23, 2009
    OK, I cut the holes for the venting which is 6" flex duct. I was not looking forward to doing it because the walls to this cab are 3/4" thick!

    I used one of those cutout tools and dust was getting everywhere. Then I cut another 6" hole through a shelf which was even dustier, and lastly drywall.

    Then I had to get into the crawl space and run the flex down from the top, through the 3 holes and into the cab with plenty to spare inside if i need it. I moved the fan up into the space and connected the flex duct. Then I went to turn it on.

    Man is it ever loud! I thought I'd cut down a lot of noise by having it up in the attic. But I think a lot of sound is being transmitted by direct contact with the ceiling boards.

    So as it is now, I have the fan off, but I'll try to suspend the fan housing from the roof boards and see if that's any better.

    But i want to get another fan. I'd like to get something very quiet yet powerful enough to pull through 8' of 6" flex with two 90 degree bends. Also something variable speed would be great too. I can still have this loud fan up there as a spare.

    Edit: I made a request for fan info here.
  9. Honestly i have a closet 18x36x64 and i have a 400w hps 10inches above the top of my 3 plants. As long as you keep a fan on and watch for heat stress ur fine.
  10. You got it right -- sound is from vibrations being transferred, stop that by suspending the fan.

    If you want a really big fan that won't buzz, get a Stanley blower, thousands of cfm. I have one and it draws strongly through about 8 feet of 6" pipe.
  11. you should pick up a 6in duct booster fan, they work great for air-cooled lights or charcoal filters.....i went down to rona and got a fan speed control for $9bucks and they work great for adjusting fan speeds and dailing in rooms.... (DON"T get a fan dimmer, i repeat no dimmer.)
  12. Hi Biz, are you talking about this blower?


    If so, does that have a flange for a 6" duct? Is it rated for continuous duty? And how loud it is? Obviously the sound of air rushing is loud, but what about the motor? Is it loud?

  13. Thanks again!

    You're talking about something like this?


    And the controller, something like this?


    When I bought the fan I have now, I also bought some kind of controller for it, but it only seems to work full on or slow, anemic, and groaning. I've heard that only certain kinds of motors can be variable. Are those booster fans compatible?
  14. #14 toastybiz, Feb 23, 2009
    Last edited by a moderator: Feb 23, 2009
    That is the Stanley blower. It can be loud in terms of wind movement, but no vibration or motor noise. So loud in a kind of soft, whooshing way. Draws well even on low setting.

    I had to rig a way for it to draw my exhaust -- basically I took a cardboard box big enough for the Stanley to fit in, cut a 6" circular hole in one side and a rectangular hole the size of the blower's exhaust in the other. Then fit my exhaust into the circular hole, put the Stanley inside the box (so now the entire inside of the box is the draw environment), and fitted the exhaust airtight to the rectangular hole. Hope that's clear.
  15. I use a stanley blower in my grow, it serves two functions and works great. Check out My Setup in the signature. I modified both sides of the blower to accept a 6" duct.
  16. id be interested to see how the duct booster fan works for your air cooled tube and filter. i would ike to use the same fan for my setup becase its so cheap! but it will still cool the light
  17. I found this thread here from another site about this blower. I'm sold on trying it. I'll stop by walmart today and see if they have one. If not, I'll order one online.

    Biz, I think I know where you're going with the box idea. I had to do the same thing with the fan I have now. It was designed as a whole room exhaust fan with no flanges and no easy way to direct air from a duct. So I built a particle board box and mounted the fan on one side, stuck a 8" to 6" reducer at the other end to act as a flange, and sealed it all up with some calk and tape to make sure it doesn't leak.

    For the Stanley, I think I'll try something like Mr B's setup with flanges on both sides and have those running to a box or a header of some sort with a 6" flange there to hook up my duct.

    I was thinking of something high end, but the low price of the Stanley is tempting. I'll pull the trigger today.
  18. I pulled the trigger on the Stanley. I'll have to mod it, but that shouldn't be too hard. It was $49 shipped (walmart had zip: not really the season).
  19. OK, I got the fan, drilled the holes in the impeller and taped up the other side of the case. But now the fan seems to be stuck in low speed. It's either on or low. No medium or high. I opened everything back up and I cannot see anything visibly wrong with the switch or contacts to the motor.

    I'll be lucky if this thing will now work. It's got to pull through lots of flex and eventually a carbon scrubber.

    Not a good sign...
  20. #20 moon grower, Mar 8, 2009
    Last edited by a moderator: Mar 8, 2009
    Did you have to wire your fan? I have some S&P fans (which are extremely quiet) that you wire the power cord to different spots to give it different speeds.

    I grow with a 400 MH in a cab sort of similar size to yours. Mine is 20"x36"x80" inches and I usually have lots of spare height. I don't use a cooltube and my temps stay real nice in there with a 6" vortex on low speed and 2 8" darkroom louvers for intake. I use the back of the hand test as well to see if my light is too hot for my girls. I'd recommend tying them down if height becomes an issue. Also, with your cabinet so wide, I would put the tallest plants on the sides or lift the pots up with something to make your cabinet more stadium style to keep those side buds closer to the light.



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