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Thread: The Big Un's

  1. #17
    Hermopolis's Avatar
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    Quote Originally Posted by Av8tor1 View Post
    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.
    Efficiency is irrelevant when it concerns cost to operate. Both magnetic and electronic ballasts rated at 400W input will cost about the same to run. Your output efficiencies will be different, but the cost to run will be roughly the same. The objection of the original poster was that of cost. 400 watts of incandescent bulbs costs the same to run as a 400 watt refrigerator. 400 watts is a unit of consumption NOT efficiency.

    Quote Originally Posted by Av8tor1 View Post
    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
    What's your source? T5's are only more efficient than T8's at their peak operating temperature of 35 degrees Celsius, otherwise their efficiency is roughly the same. While I think that T5's are excellent light, I also think it is important to separate the data from the hype as well. T5's generally get 70-100 lm/w, while MH's get 65-115 lm/w. Furthermore, T5's also suffer from lumen maintenance issues, although they do last 33% longer than T8's. And when using T5's instead of MH's, while I admit this can be done, people often don't use nearly as many tubes as they need to really get the job done, using say 4 or 6 tubes when they really need 8 or 10. So, while T5's are appropriate for terrarium less than 18 inches tall, they are often rendered inadequate by improper implementation.

    I'm not saying that MHs are the be all and end all, but only that they can be appropriate for some situations and don't cost nearly as much as some people make them out to cost. I normally recommend that people starting a new terrarium use T5's, because (a) they are efficient and (b) a wide variety of tube color temperatures are available, which can contribute to a highly aesthetic color of lighting. However, I have used MHs for years and have not suffered from the issues often described on the CP sites.

    In the end, it depends. You have to use what is appropriate for your situation. If you have a hammer, one tends to see every problem as a nail. Likewise, if one has T5's, it is a mistake to see them as the answer to every lighting problem. Sometime it is. Sometimes it isn't.

    -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.

  2. #18
    Tony Paroubek's Avatar
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    T8 tubes are lower in lumen output than the t12 because they use less power. A 4' T8 is 32 watts vs 40 watts. I would not bother with them for your plants. Many buildings use them because you will hardly notice the lower light ouput and they will save 8 watts/bulb. Your plants will notice the difference though!

    They do make electronic ballasts for MH systems. The problem with your setup is the length. You would need a bunch of lower power MH bulbs to evenly light the 8' length. And to get the proper light for the depth of it I think you would want something with more intensity than normal fluorescent. You can't make up for the distance by simply adding more normal tubes. You need a brighter bulb to do that. Which means more electricty....So until LED or Plasma lamps are perfected you are stuck with power hungry HID or HO fluorescent
    Is that a Nepenthes in your pocket or you just happy to see me?

  3. #19
    Av8tor1's Avatar
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    Quote Originally Posted by Hermopolis View Post
    Efficiency is irrelevant when it concerns cost to operate.

    -Hermes.
    Wow... now that is a statement

    when you go buy a 400w MH they are referring to the bulb wattage, not the actual wattage of the fixture. If that was the case then the bulbs you buy would be rated less... and be rated depending on the specific ballast you were using.

    T5's aren't the right fixture for everyone, and you sure are right...there are lots of incorrect hype and tribal knowledge...

    T5 is 54w, T8 is 32... T5 is 5/8" T8 is 1"

    So the t5 is dissipating more energy over a smaller surface are... intensity is higher, and the smaller diameter increases reflector efficiency as well

    so on several levels T5 is more efficent the T8

    What source?... how about common sense for one



    Av

  4. #20
    Hermopolis's Avatar
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    Quote Originally Posted by Av8tor1 View Post
    when you go buy a 400w MH they are referring to the bulb wattage, not the actual wattage of the fixture. If that was the case then the bulbs you buy would be rated less... and be rated depending on the specific ballast you were using.
    Ah, if you were a professor worth your salt, then you would have been careful about reading my post and noticed that I was referring to input wattage of the ballasts. I made no reference to the bulbs themselves. Now, you are quite right some input wattages of ballasts do vary, which is why I qualified my post with the words "about the same." However, if I have a MH ballast is rated for 400W bulbs that draws 456W watts input then it should cost slightly less than an array of T12s that draw in 480W watts input. To say otherwise is magical thinking.

    Quote Originally Posted by Av8tor1 View Post
    Im just a licensed deep and surface mine electrician, ISCET certified industrial electronics tech, FAA A+P licensed, FCC GROL license, licensed Infrared Thermographer etc.

    Oh and for a living I'm Professor of Industrial Sciences..

    But obviously I'm way out of my league...
    Good for you. And maybe some day you'll have a college degree to go with all those licenses.

    BTW, I don't have anything against electricians. My father is an electrician. I just dislike people who parade certificates in lieu of arguing the facts of the case. Appealing to authority is just another kind of faulty reasoning.

    -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.

  5. #21
    Av8tor1's Avatar
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    Quote Originally Posted by Hermopolis View Post
    Ah, if you were a professor worth your salt, then you would have been careful about reading my post and noticed that I was referring to input wattage of the ballasts. I made no reference to the bulbs themselves. Now, you are quite right some input wattages of ballasts do vary, which is why I qualified my post with the words "about the same." However, if I have a MH ballast is rated for 400W bulbs that draws 456W watts input then it should cost slightly less than an array of T12s that draw in 480W watts input. To say otherwise is magical thinking.



    Good for you. And maybe some day you'll have a college degree to go with all those licenses.

    BTW, I don't have anything against electricians. My father is an electrician. I just dislike people who parade certificates in lieu of arguing the facts of the case. Appealing to authority is just another kind of faulty reasoning.

    -Hermes.
    LOL, oh i have the degrees... but they are in aerospace and electronics

    You do dance well, so it doesnt matter what the bulb does, or how it performs in your arguments

    Here is a white paper on T5 vs Super T8's vs. HM

    if you read it you will see MH has a 35 % reduction in output at 40% life

    Whereas the T5 and super T8 is less then 10%, It also describes the increase in efficiency

    Efficacy, in review, is an expression of relative lamp efficiency. Expressed in lumens of light output per watt of electrical input, this useful metric is similar to “miles per gallon.” As lumen output decreases over time, efficacy decreases because wattage says the same.

    400W probe-start metal halide has an initial lamp-ballast system efficacy of 79 lumens/W. Although well below the efficacy of Super T8 with its efficacy of 99 lumens/W, it is only 7% less efficacious than T5HO with its efficacy of 85 lumens/W. However, initial efficacy is virtually meaningless because efficacy changes during operation. At 40% of lamp life, considered the design average, the efficacy of a 400W probe-start lamp-ballast system drops 40% to 51 lumens/W, while T5HO and Super T8 efficacies drop 5% to 81 lumens/W and 94 lumens/W respectively.

    http://www.aboutlightingcontrols.org...-low-bay.shtml
    (super T8's are not the typical T8 but a high output version)

    Heliamphora have long been considered the gold standard when it comes to CP light requirements,
    Ill show you mine and you can show me yours, lets put our money where our mouth is

    I just dislike people who parade certificates in lieu of arguing the facts of the case. Appealing to authority is just another kind of faulty reasoning.
    Oh i totally agree... thats why i tried to edit it before anyone saw it... my apologies

    But as you can plainly see, its all about efficiency... to just compare input watts as a way to select a good plant light is as you say "majical thinking" and "faulty reasoning"

  6. #22
    Hermopolis's Avatar
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    Quote Originally Posted by Av8tor1 View Post
    Heliamphora have long been considered the gold standard when it comes to CP light requirements, Ill show you mine and you can show me yours, lets put our money where our mouth is
    It would not be a fair contest since I'm only restarting my collection. But I will be posting pics of my terrarium in the not too distant future. Although I don't have any heliamphora to do a proper comparison... would you care to toss one of your extras my direction? Even if I'm wrong, I might still be able to get a free heliamphora out it.

    Nevertheless, you are certainly a worthy mind, a scholar, and a gentleman.

    -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.

  7. #23
    swords's Avatar
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    If you can't get them arguing politics get them arguing lamps!

    Not quite how I envisioned the post would go...

  8. #24
    Tony Paroubek's Avatar
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    More power through the lights = HO and VHO. And yes.. they use more electricity.

    You really need to shop around, for example the normal 8' T12 comes in 60 and 75 watt tubes.
    High output 8' T12 comes in 95, 110, 185, and 215 watt tubes. The difference, aside from the obvious much higher lumen output for the higher wattage tubes, is the high wattage tubes are designed to hold up to the higher output ballasts. If you put a normal tube in a HO fixture it will light but it will burn out faster.

    For your setup though I think you will have to make it a DIY system. Select the bulbs and number you want based on your lighting needs and then get the proper ballasts to power them. You may also need a different end cap than the typical bipin fixture. Some of these HO bulbs have different pins/connectors on the ends. Compare ballasts carefully as well because there are many different makers and they will vary on their power consumption and other factors such as magnetic vs electronic, rapid start, instant start etc. All of which can effect bulb life among other things.
    Is that a Nepenthes in your pocket or you just happy to see me?

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