Shop lights

The part that creates the light. I don't know what sort of ribbon light this is but if it's designed for illumination, you can bet the junction is getting quite hot. If it's just for looks, it may be much lower power.

Correct, most High output Leds have heat sinks and the lights themselves get hot.

A friend bought me a Nitecore flashlight for woodworking I did for him and some machining. The light from it can light up a building 600 feet away like daylight. When it's on highpower the glass on the front gets hot, and the front end gets hot.

Also if you look on youtube you will see led flashlights that require cooling.

Power supplies are sources of heat, but more likely the devices heat sink is extended into the base where the power supply is enclosed.

The LEDs used in ribbons are not high power devices and there are hundreds of them on a standard 16' reel. Each individual LED is only dissipating a fraction of a watt.

-BR

At least for consumer lighting, the failure point is typically the power supply, more specifically the electrolytic capacitors which dry out and are degraded by heat. The LEDs do fail, mostly from the same heat degrading the thermal bond between the actual LED emitter and the heat sink, but often the root cause of this is poor assembly. LEDs as devices are very stable and robust, as long as they operate within there design specs for maximum junction temp.

-BR

The "better" LED lights are those designed as a fixture with the LEDs separate from the power supplies. It's all heat management. Trying to cram lots of Lumens into a standard dimension Edison style bulb that is crammed into a fixture that has no provisions for air flow is really pushing it.

-BR

I use a lot of these LED strips in lighting projects, never need any heat sinks.

Specifically the typical LED used in strips is the "3528" surface mount device. 4 to 8 Lumens at 0.06 to 0.08 Watts of power. Even the "high density" strips with 600 of these parts (over 16') dissipates less than

-BR

On 11/19/16 9:54 PM, Leon wrote: s.

Those LEDs (3528s) have ceramic cases. The heat is conducted through the electrical contacts to the copper traces in the ribbon. At 0.08 Watts, that heat is dissipated quickly.

-BR

The point where the light is emitted from will be hot. Getting rid of that heat is the secret of semiconductor life. How much current is at each led will determine how hot it is, well designed leds lights will not burn you a bad one will. The higher the current at the led the shorter the life of the led.

In other words you picked the right led lighting system.

Mark

Based on forensic analysis of how many failures of consumer LED replacement bulbs over what span of time?

Exactly.

Well, not for looks, these light up our kitchen counter tops and the length of my wife's long arm machine. Lighting is critical on the long arm machine. But there are hundreds of LED's on that ribbon, IIRC 3 per inch along 11 feet.

Even still, dissipated quickly or not one would think that if you are touching, pressing your finger hard enough into the ribbon to leave an imprint that you would feel something.

I have to think you have the answer. ;~)

Either way, these are the last set I bought, the previous set was from LeeValley. These weare about 1/2 price compared to :LeeValley

Understood but the point I am trying to make is that not all LED lighting gets hot. I have single bulbs that get hot at the base and some at best get ever so slightly warm after touching for several seconds. All of the cool ones are attached to a wood product and stay on for hundreds/thousands of hours at one time. I get more warmth from my LCD computer display screen.

No, it's all heat management. Separating the supply from the business end may, or may not, be part of that.

No, all get hot. How hot is the difference between ones that will last and ones that won't. Note that "not that hot" may be enough to burn a finger (100C or above), if you could touch it.

I going to agree that hot is relative. My LED's don't get much more than room temperature.

Again, the surface may not be much more than room temperature but the surface temperature of the fixture isn't important to the LEDs reliability.

I follow the LED industry as part curiosity and I also build some custom LED lighting devices. This means I read a lot of stuff about failures and always read through the various "tear-down" articles where they dissect new lamps and also do forensics on failed units. With anything electronic, the manufactures produce reliability figures (MTBF, mean time between failures) for components and also degradation numbers tied to life-killers like heat.

Some of the trade journals touch on this stuff. If you are really curious (or really bored 8^)

Some general info, seems reasonable given the source:

-BR