Led actual watt/power
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Old 02-24-2013, 06:50 PM   #1
Jnad
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Led actual watt/power


Hello!

Different led light is flooding our hobby, many are good products and some not so good. Often i see led products labeled 10, 20, 30, 50W of power and so on.

I am an electrician ingeneer and i have done some mearsuring of some led products when i was in to saltwater tanks. Actually i have tested three led fixtures/bulbs for the actually power, and i have been diseapointed.

I would encourage those of you that can to do som tests for the actual power, I am especially suspicious of those chinese led flood lights that claims 20W and above.

If someone do some tests i hope you will post it here.

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Old 02-24-2013, 10:37 PM   #2
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Much more important than the power consumption is the PAR they produce at the appropriate distance for your tank. LEDs seem to be described as X watts based on simply multiplying their maximum forward voltage drop times their maximum current. But, the LED bulbs that contain a LED driver as well as the LED junctions, may not run the LEDs at their maximum power consumption.
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Old 02-25-2013, 05:37 PM   #3
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But, the LED bulbs that contain a LED driver as well as the LED junctions, may not run the LEDs at their maximum power consumption.
Not to mention there can be 100% variation in PAR among different bins for one single model of LED, run at a given power level. Start comparing different models or manufacturers of LED (even when run at the same power level) and the variation can be many hundred percent. And then there's the fact that LEDs are, inherently, able to run happily over a wide range of power levels (unlike, say, Florescent or metal halide lighting) and things get even more complicated. An LED sold as a "3w" LED will be perfectly happy (and more efficient) run at 1w.

For me, all this boils down to this - if you are trying to compare different units, you MUST be sure you understand the specific numbers and what they mean. Even if a bunch of different fixtures did actually consume the power they were rated - say, 50w - the output in terms of PAR could be worlds apart. Wattage only matters in terms of how much it'll cost on your electric bill. It's a very, very, very poor indication of what it'll mean as far as growing things in an aquarium. If you're going to compare different LEDs or different fixtures, PAR is a much more meaningful number (though, again, even with PAR there are issues).
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Old 02-25-2013, 07:56 PM   #4
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Hello and tanks for answers!

I perfectly see and agree in the two post above, par is the most important.

But what i wanted to say with my post is that products very often is not what the ad says it should be, ads often are very misleading. For example when a flood led bulb ad says 30W power, the ad is formulated a way to make us consumers assume that this product is 30W of actual consumed power of light. But this is not always the reality.

Just wanted users of this forum to be aware of this, even though par is the most important i belive most of us still looking for watts beacuse it is not so many led products that is labeled with real par values. Of course there also is serious products out there that is labeled with real par values.

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Old 02-25-2013, 10:58 PM   #5
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A multiple LED junction light bulb could be made that would consume say 10 watts, or 20 watts, and still produce the same amount of light. In other words, the LED driver circuit can be made to be very efficient or very inefficient, and the cost and heat problems are what will determine what the manufacturer will do.
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Old 02-26-2013, 04:23 PM   #6
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I think i understand what you saying, my English is not so good

But, you say that for example a led bulb could have leds rated for 3W but the led driver running the leds for only 1w. In some cases beacuse of poor driver, and sometimes it could be intended to for example save the leds for longer life.

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Old 02-26-2013, 05:01 PM   #7
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I think i understand what you saying, my English is not so good

But, you say that for example a led bulb could have leds rated for 3W but the led driver running the leds for only 1w. In some cases beacuse of poor driver, and sometimes it could be intended to for example save the leds for longer life.

Jnad
The designer of one of those LED bulbs would make the decision about how to drive the LED junctions based mostly on the costs involved. If the bulb is intended to sell very cheaply the driver circuit will need to be very cheap to make, and the heatsink requirements must be very easy to meet. I suspect this will always cause the designer to use much less than rated power for the LED junctions. But, the people who sell the resulting bulbs will want to claim whatever will cause more people to buy the bulb. Obviously that will mean they will claim the highest power rating for the bulb that they can get by with. So, they will multiply the maximum power rating of the LED junctions by the number of LEDs and claim that as the power rating. And, of course, those sales people are unlikely to even know they are being deceptive.
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