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Kichler LED Fixtures - True Wattage

Discussion in 'Landscape Lighting' started by JimLewis, Dec 22, 2010.

  1. JimLewis

    JimLewis LawnSite Fanatic
    Messages: 6,872

    Something I learned yesterday about the Kichler LED light fixtures kind of frustrates me. I am told that when designing systems with their LED fixtures, you have to account for more wattage than the fixture is actually labeled for. For instance, if you're using their 8.5 watt spot light, you need to account account for 12 watts. I was like, "Huh???" The rep. (from my supplier, not from Kichler) explained to me that he didn't understand it perfectly either but from his understanding it was something about how the LED fixtures aren't as efficient. So while they put out 8.5 watts of energy, they use 12 watts of energy to do so. Something about using more amp watts than a normal fixture??? That's when I got really confused. Not sure what amp watts are.

    Anyway, WTF? If the fixture consumes 12 watts, then why not just call it a 12 watt fixture? Why label it 8.5 watts but then tell everyone "Oh, sorry. That's just on the output side. You're actually going to need 12 watts to power it." Just call it a 12 watt fixture then, right?
  2. Tomwilllight

    Tomwilllight LawnSite Senior Member
    Messages: 284

    As I understand it, there is always some power lost to (or "used by") the driver in an LED lamp. This is very similar to the Ballast Loss issue when calculating loads for HID and Fluorescent lighting. Ballast Loss varies depending on the type of ballast used to power the light source.

    The takeaway: unless the LED's specifications list the System Watts, the manufacturer may not be disclosing the actual watts used to power their lamps. They are listing the watts consumed by a portion of the system only - the LED(s) - not the entire system (driver + chip) required to make the lamp work.

    Somebody who understands the calculations for Power Factor should step up here and help us out. I'm over my head trying to balance my check book.

  3. JimLewis

    JimLewis LawnSite Fanatic
    Messages: 6,872

    Yah, that's basically how it was explained to me too. But regardless of why, it's all sort of B.S. to me. Just call it at 12w fixture, if that's what it uses.
  4. sprinklerchris

    sprinklerchris LawnSite Senior Member
    from Georgia
    Messages: 281

    Most of the other LED manufacturers are rating their fixtures at actual watts consumed. Wonder why the desire to be misleading?
  5. S&MLL

    S&MLL LawnSite Senior Member
    Messages: 751

    They don’t desire to be misleading. In many of the catalogs it puts a chart right next to the LED section. Part of a installers job is to know the product he is installing. This is something they cover in slideshow they do at open houses. So maybe the problem falls on your distributor. Kichler tells there reps to tell the distributor. Distributor tells you….. And its less then 10 percent. But let me ask you this question. Are you designing a system with such tight tolerances that you cant allow for something so small? 9 watt is really a 12.4 . That is 3.4 watts.

    And just a fyi Im pretty sure for the past 2 years they have had them labeled them correctly. 12.4 watts is what its called in every book in my office and on their website.
  6. bcg

    bcg LawnSite Bronze Member
    from Tx
    Messages: 1,865

    There are actually 2 ratings on the fixtures, the wattage and the VA (volt amps). In most cases, wattage and VA are the same but when you have the driver or ballast, they are not. You always need to design to VA, not wattage. It's always going to be the higher number and shows your true power comsumption.
  7. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Messages: 4,102

    Check your math there: 3.4 watts discrepancy on a 9 watt rating is 37.7% 3.4 watts discrepancy on a 12.4 watt rating is 27.4 %

    Either way you slice it, it has the appearance of being somewhat inefficient. It would be more concise and accurate if the product is labeled and rated for the total power it consumes.
  8. S&MLL

    S&MLL LawnSite Senior Member
    Messages: 751

    You caught me :hammerhead: My math was not to good on that one. But still 3 watts is not gonna kill you.
  9. JimLewis

    JimLewis LawnSite Fanatic
    Messages: 6,872

    When you multiply it by 20 or 30 fixtures, that 3 watts can make a difference, yes. It makes a difference on which transformer you purchase or budget for. And it would suck to get that far into a job just to find out that you need to upgrade to a larger transformer. Customer isn't going to be too happy to hear about an upcharge.
  10. emby

    emby LawnSite Senior Member
    from Ontario
    Messages: 380

    If you really want to see what its drawing use your amp meter around one of the wires feeding the light. Find out the exact voltage and use OHM's law to find out the wattage. I(amps) x E(voltage) = P(watts)
    When we first started replacing incandescent lamps in the electrical field we performed this test and we were very surprised of the results compared to the marketing information provided. Some of the electronics consumed more wattage than the LED itself.
    Any how I hope that helps for the people wishing to perform the experiment themselves.


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