Need advice on a fan for my HPS light

Discussion in 'Grow Room Design/Setup' started by vashigopal, May 11, 2010.

  1. Thanks! I just thought of something. My current fan is 80 CFM and the air coming out of it is 107. The TD100 is 100CFM, so it will be pulling the air faster, and each "unit" of air will spend less time around the bulb. So the air coming out of the lamp will be less than 107. Does that make sense? On the other hand, there will be more resistance than I have in the current set-up because I plan to put a filter on the outlet, so the actual CFM will be less than 100CFM. I don't know. I really want that fan because it is good quality and quiet and reasonably priced, but maybe I'm cutting it too close with the teperature limits of it.

  2. Nope I think you just realized how I was thinking earlier. I didn't explain it that way, I apologize. Essentially with more air the temps should be lower because it cools the bulb back down to room temp faster (never gets there obviously). Faster the air the less time it has to pickup heat but more airflow = more chances so overall things are cooler.
  3. sorry if im droppin in ur convo
    i was wonderin if i could get some advice on my lighting
    alright im shopping for lights im pretty sure i want a 1000w mh/hps. i dont really have much electrical experience, so anyway wondering about ballasts im liking the lumatek 1000w digital dimmable but its alittle expensive for me what are your opnions on:

    digital vs magnetic
    dimmable vs regular
    diy ballasts?

    would i save money in the long run on a digital ballast?

    im gonna work all summer to get my lights plus tent n fans
    -mj 510
  4. Yeah, when I had that realization I thought, " Oh, that's what he was saying." Doh!:smoking:

    So, do you think I could get away with putting the TD100 right on the lamp, the way I have the cheap-o duct fan now? Would the air going in to the fan be less than 104? (I know that's an impossible question!) If I were to add elbows and put a filter on it, it may reduce the airflow to less than 80CFM and the cab temp would get worse. But if I put the fan directly on the lamp I know for sure I'll have 20CFM more than I have now.

    The way I have it now, there is enough space in the top of the cab to corral the hot air until the PC fans can pull it through the filter. (Actually after I took this picture I added a short vertical length of ducting to direct the hot air towards the filter.) I'm lucky that my plant didn't grow too tall!

    I'm also planning to replace one of the PC fans with a better one, so that will help. The a/c cools the room to 68 now, but everything will change when the weather gets a few degrees warmer. In summer I'm lucky if I can cool that room down to 80 because there's no door. (And I won't be able to grow in the summer, obviously.)

    After this grow I'll re-vamp the exhaust system. Right now it's a bunch of mistakes cobbled together that barely manage to get the job done.
  5. Sorry, mj 510, I didn't see your post. I'm no expert, but I'm wondering why you want a dimmable light? As far as ballasts go, I only have experience with a 150W magnetic, and it does make a hum and some vibration, and some heat. Actually, it gets burning HOT, but it's attached to my light so that's the likely culprit. The electronic ones are supposed to be quiet and produce less heat. If you can keep the ballast outside of the tent, your plants won't know the difference. But if you need to keep it inside the tent, the electronic one would save you some unwanted heat. It would also save you some money on electricity, but you'd have to find the specs (which is harder than it should be), to figure out exactly how much you would save.

    As far as a DIY ballast, I saw a thread on how to make 70W magnetic ballast, and it used a PC power supply box. For 1000W you'd need a much bigger box. I'm comfortable with wiring small electrical projects, but I would be more comfortable buying a 1000W ballast. By the time you buy the box and all the parts, how much would you save?

    You'll get more responses if you start a thread with your questions. Good luck with whatever you decide to do!

  6. Digital > Magnetic in every way except upfront price and repairs

    Dimmable vs Regular - nice feature but unless you have solid plans to utilize it, not something you want to spend more on.

    DIY - I am big on DIY but thats one thing in my room I wouldn't fuck around with.
  7. Vash:

    Too bad you can't mount the fan on top or on the back of your cab, would solve vertical problem.
  8. Yes, it's too bad. Behind the cab is the public hallway:eek: On top is the little shelf with the 2 PC fans, above that is kitchen storage. Sometime in the future I may renovate the upper cabinet and make a veg chamber up there.:rolleyes: (dreamin of the future)
  9. Lookin good.

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