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Thread: The Big Un's

  1. #9
    Tony Paroubek's Avatar
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    Av answered about the ballast power usage so no need to answer much on that other than to say deffinately take a look at the ballast since it uses power also. Electronic ballasts will save you money as they use less than the magnetic coil type!

    You can't really compare the 8' to the 4' in lumens since the 8' is twice as long it should have twice the lumen output. But you deffinately need to look at all the bulbs available in the size you are looking for since they can vary as much as 30% between them for bulbs of the same size and power.
    Is that a Nepenthes in your pocket or you just happy to see me?

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    Av8tor1's Avatar
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    In addiion to spectra and CRI

    Av

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    Quote Originally Posted by swords View Post
    I used a 400W MH over my LL tank years back and even though it was only 400W it cost me twice as much to operate as 400W of Fluorescents (actually 480W of NO T12s), have you any idea why that would be? Shouldn't 400W be 400W? Does the MH ballast also pull power for itself and not just the bulb?
    No, a 400W MH ballast does consume 400W and should not cost you more than running 480W of NO T12s. The watt rating for MHs is the total power of the ballast/bulb combination and will not run you in excess of that rating. MH ballasts do have considerable power losses due to heat (up to 20%); however, they more than make up for this inefficiency by putting out more PARs.

    One reason it may have cost you more could have been time of year. Power companies charge different rates depending on the time of year. And they commonly "estimate" your power bill in winter months in such a way as it can cost you 3 or 4 times what you actually use. I have this fight with my electric provider every year, where they estimate a $300 power bill when the actual meter reading will result in only an $80 bill. A lot of people try MHs for the first time in the winter and experience the sticker shock--people generally don't do MHs until they think they need them, which is when Mr. Sun has decided to take a vacation from the northern hemisphere.

    The problem here is that you are comparing apples and oranges. 400W is 400W for input. The same is not true of output. According to National Garden Wholesale in order to get 50,000 lumins, you need either a single 400W HID lamp or 10 4ft 54W T5's or 42 4ft 40W T12's. [http://www.nationalgardenwholesale.c...plemental.pdf]

    -Hermes.
    "The grass withers, the flower fades. But the word of our God stands forever." (Isaiah 40:8)

    My Grow List Updated Oct 22/2010.

  4. #12
    swords's Avatar
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    Yes, I realize a 400W MH isn't the same intensity of output of NO FL but the operating price difference was quite astonishing. It was not an electronic ballast but an older style one from a guy online who was changing his SW Reef lighting over to a new electronic ballast setup so he let me have it cheap and gave me a 175W ballast for free. Since I was growing my huge LL Neps in a full size tub/showerstall I wanted a heavy duty lamp to do it and it did well but cost a fortune.

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    Hermopolis's Avatar
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    I don't doubt that the price difference was astounding. I'm questioning why it was astounding, because 400W of MHs should cost you no more than 400W of T12s. Since this is input wattage we are talking about, they should be equivalent in cost to run. Perhaps, you miscalculated the input watts on your flourescents. Are you calculating the 480W by number of tubes or by number of fixtures?

    -Hermes.
    "The grass withers, the flower fades. But the word of our God stands forever." (Isaiah 40:8)

    My Grow List Updated Oct 22/2010.

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    Av8tor1's Avatar
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    Quote Originally Posted by Hermopolis View Post
    No, a 400W MH ballast does consume 400W and should not cost you more than running 480W of NO T12s. The watt rating for MHs is the total power of the ballast/bulb combination and will not run you in excess of that rating. [http://www.nationalgardenwholesale.c...plemental.pdf]

    -Hermes.
    I have to respectfully disagree, you take 2 400w MH bulbs, run one in an old fashioned magnetic ballast and run one in a new electronic ballast... due to hysteresis, power factor and other losses the magnetic ballast will be considerably less efficient.

    big problem with MH is the lumen maintenance, they lose efficiency very quickly and the overall efficency is considerably less then T5.
    their typical PAR efficiency measured in uE/s/Watt is 0.48 when compared to a common T8 (i dont have T5 data handy) it's 1.2, over twice the efficiency...and even less efficent when compared to T5

    the increase in efficency is the reason industry is replacing their HD with T5's



    Av

  7. #15
    swords's Avatar
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    So are NO T8 or T5s 32W better than old timey NO T12s even though they don't have the same lumen output? Just curious as I've always been a T12 man going by the lumens rating.... Since I can grow and flower Neps, Orchids and succulents with NO T12s.


    Back the the MH for a sec, I was calculating on the number of tubes and the power bill. It would be interesting to see what the dif in power bills would be between the old style MH and the newer ones. I'm not in contact with the guy I bought the MH from to see if switching reducing his running costs for his reef.

    OFF TOPIC: The guy had an overflow that dropped through the living room floor to a 100+ gallon refugium / sump in the basement and then back up to the display tank in the living room - that was wild!

  8. #16
    Tony Paroubek's Avatar
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    Wattage of the bulb is simply how much the bulb uses to light properly. For the real power consumption you need to look at the ballast and find the INPUT wattage.

    A magnetic ballast for a 400w MH bulb will typically be around 460 input watts.
    A magnetic ballast for 2 4' 40w T12 fluorescent tubes is about 86 watts. x 5 = 430 watts
    An electronic ballast for 2 4' 40w T12 fluorescent tubes is about 72 watts x 5 = 360 watts
    Is that a Nepenthes in your pocket or you just happy to see me?

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