100Watt Floodlights Without LED Driver, Gets too hot

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  #1  
Old 06-30-16, 04:44 PM
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100Watt Floodlights Without LED Driver, Gets too hot

Got these off eBay and decided to look inside before installing them. Two thing are making me weary about installing them -
1-They have no LED driver, only a circuit of some sort
2-Testing them for 10 minutes they got so hot (on the back) to the point you cannot rest your hand on them.
So are these 2 observations normal for these units?

Trying to be cautious here, I am afraid to install them until I know if they are safe.





 
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  #2  
Old 06-30-16, 05:52 PM
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It is probably a series connected string with a simple AC rectifier and current limiting resistor instead of a constant current driver. Not unreasonable for an inexpensive floodlight.

If it's really 100 watts (which means it should be really, really bright, like 8000 lumens), most of that is dissipated as heat, not light. So imagine a 90 watt incandescent bulb in that small housing. It's going to get quite hot. Probably not so hot that they are dangerous, as long as they are installed in the open, but hot enough that the lifetime will be poor.
 
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Old 06-30-16, 07:32 PM
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Did any of their literature state the lumens as CT stated.

If you are looking for an equivalent 100 watt flood light, then it should only be 23 watts (or so) of electricity. What is your application?

Bud
 
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Old 07-01-16, 04:43 AM
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Thanx for fast replies guys-it's why I like this forum, and good teachers.
The lights are bright but didn't take my breath away. A single one does not turn my backyard into a daylight. In fact beyond 30ish feet it's brightness is not that effective.

@CarbideTipped
Great explanation, but a little over my head.
1-What does a limiting resistor, and a constant driver do?
2-Would it improve anything if I could add/install an LED driver? In other words what is the difference (general, electrical performance, brightness) between this light and one with an LED driver?
3-Considering it has this type of circuit is it possible to add an LED driver?

@Bud9051

Application : I was just looking for bright lights to replace the lights above the garage door.

Here is what I can gather from the listing,

Details:
Power: 100W
Emitting Color: Cool White
LED Color: 6000K-6500K
Input Volatge: AC 110V
Lumen: 8000-9000 Lumens
Size: 286*237*65mm (L x W x H)
Waterproof : IP65 to protect against ingress of dust and against standard water jets with a nozzle
Life time: > 50,000 hours
Lens covered with waterproof material
Shell material: Aluminium
 
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Old 07-01-16, 04:53 AM
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The circuit board you are seeing is the LED driver. It might not be a separate circuit board but it's performing the function of a driver. So, adding another driver would cause a problem unless you remove the LED emitter from it's current driver board.

What you've got is a 100 watt light. It's not a 100 watt equivalent which is actually running at 20 watts. The data plate is saying it draws 100 watts. So, you're going to get a lot of heat and it looks like they are using the housing as the primary heat sink for cooling. I would certainly mount it so the back is an inch or so away from anything to allow for good airflow to aid cooling.
 
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Old 07-01-16, 05:41 AM
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8 to 9,000 lumens seems like an overkill and 100 watts defeats the objective of an economical flood light, IMO. I installed this one a year ago at my daughter's house and I was glad it was up high, peak of tall gable. Shop Utilitech Pro 180-Degree 2-Head White LED Motion-Activated Flood Light at Lowes.com I would not want to look at that light straight on very often. At 2,000 lumens it did a great job of lighting up the entire front yard and having 2 heads gave it a wide display, probably a 50' x 50' area.

As PD said, what you have is probably safe to use, but it will get hot.

One of the problems with LEDs is they are so new few of us can relate to what we are buying and buying different lights just to try is not practical.

Bud
 
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Old 07-01-16, 06:50 AM
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Good points but maybe the objective actually was to
turn my backyard into a daylight
in which case it's probably a better choice than an old-tech sodium light.
 
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Old 07-01-16, 12:33 PM
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ok. Sounds like the lights are safe to use. I was worried if the amount of heat is a fire cause risk. I have and will create ample spacing.

BTW If I removed that circuit and added an LED driver would that be beneficial in any way? (Risk of fire is my main concern because my lights run 9pm-6am thanx to TXU energy free nights plan)
 
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Old 07-01-16, 01:06 PM
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That is a self contained self ballasted unit. You cannot modify it or change it and have it work reliably. That light is designed to produce 100 watts of light as such will produce 100 watts of heat in the process. Those LED's are in a series string with a current limiter.

An LED driver is a fancy name for power supply. Most LED drivers are used with single LED fixtures.
 
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Old 07-01-16, 03:52 PM
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One more question - my buddy says they have a CE listing I guess accepted in Europe but are not UL listed and thus, not accepted in US. Should that be a cause for alarm not to use them?
 
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Old 07-01-16, 05:40 PM
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Now you are worried about a UL or TUV CE logo? If you have spent this much time worrying about this light and seem hell bent to re-wire/re-engineer it with another LED driver why not just go get another light. Something you are comfortable with.
 
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Old 07-02-16, 04:44 AM
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Not worried but cautious before I do stupid, only because my buddy pointed that. So I thought I would run that by you guys. I am a new home owner, and DIY enthusiast in a completely different line of work. So just now I am learning there's a quite a bunch I don't know about these stuff. From everyone's advice I won't re-wire them. I am pouring every $ into the mortgage, so when I saw 2 of these for $35 I thought it's a deal. Now I realize I put my cart in front of the horse. I can only ask. But appreciate everyone's input.
 
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Old 07-02-16, 05:03 AM
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Hi bambata,
There is a learning curve to everything and certainly owning a home. As for modifying anything electronic it shifts all responsibility for any future problems, like a fire, to you. A UL listing isn't a guarantee but it does say the equipment has gone through some level of testing and it is something insurance companies look for in case of a claim.

As for finding a flood light at a good price, that long warranty is also part of the value and when purchased online from XYZ company, who would you go to for a warranty claim. In my area I will frequently use the big box stores and save the receipt and bar code cut from the packaging. But even with that, many of these claims of 30 plus years will never be challenged.

Enjoy your new home,
Bud
 
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Old 07-02-16, 06:59 AM
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when I saw 2 of these for $35 I thought it's a deal.
It is actually a deal. A good deal... probably not.

I install parking lot lighting and based on the cost of those fixtures I would severely doubt the longevity of the ones you were interested in. You mentioned they run extremely hot and that would indicate a short expected life.
 
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Old 07-02-16, 08:36 AM
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LED units do give off some heat. The ribs on the back of the unit tell me that there is considerable heat and the ribs give the back more surface area for heat dissipation. All the diodes (the yellow dots) so closely spaced tell me that a lot of heat is being generated within a small space.

For any given floodlight light fixture or lamp, the light intensity diminishes with the square of the distance. So your 8000-9000 lumen fixture actually consuming 100 watts should deliver about the same light intensity at 30 feet as a 1/4 strength (2000 lumen or thereabouts) "100 watt incandescent equivalent" LED fixture of the same geometric shape and size delivers at 15 feet.

It's too early to say and there is not enough information given us to say whether your fixture is "China made quality" so as to not last as long as a fixture with a better LED driver. For typical LED fixtures (and CFL fixtures) the ballast or driver is usually the first to fail when the lamp or LED unit is installed in too close a space.

You will need electronics engineering experience to substitute an alternate LED driver.

Given one of your fixtures (100 actual watts) compared with four or five fixtures of similar physical size and 1/4 to 1/5'th the actual wattage and lumens each (e.g. 20 to 25 actual watts; about 100 watts incandescent equivalent, 2000-2500 actual lumens), the single fixture is more apt to fail sooner because all the heat is generated in one place.

A resistor (as a current limiting device) can be a very simple LED driver. It can be very energy inefficient since much of the power in the lighting circuit might be dissipated in the resistor as heat (depends on supply voltage versus LED voltage requirements and LED configuration. This is in addition to the heat given off by the LED diode itself. Circuits (say, on circuit boards) are designed to give the LEDs the proper voltage and current while dissipating less heat within such circuits compared with plain resistors.
 

Last edited by AllanJ; 07-02-16 at 09:05 AM.
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Old 10-18-16, 01:16 PM
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UPDATE:
I installed this light above the garage door since the end of June. So far it has worked flawlessly. The light is bright & powerful enough that it lights up all way to the garage doors of my immediate, and 2 opposite neighbors. They would be just fine if they didn't light up their floodlights. So I have decided to add another unit to the backyard.

Thanx everyone for your input.
 
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Old 10-19-16, 06:36 AM
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If you get bored look at bigclive.com and his Youtube channel. He's en English guy who has done a lot of videos about that style and other LED lights. He has test equipment and runs them through their paces. It's amazing how many poor quality LED panels are out there and there output is nowhere near what they claim.
 
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