# LED heating up



## vallyfarm (Oct 24, 2006)

I thought LEDs are so efficent because they convert almost all power into light. I installed a 13.5 watt, 800 lum into a table lamp, but the light was too directional. The "light bulb guy" at the store said it would be perfect.  Well, if I was trying to light the ceiling he would be spot on. So I went to put it into a reading lamp, but after just 5 min The big base of the bulb was hot. I mean HOT. Like as if it were an incandescant bulb. The base looks like a heatsink, but are they meant to be this hot? Mike


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## Ross (May 9, 2002)

Apparently so as the few I have do this too. Still a lot of light for the wattage and heat's not so bad in winter.....


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## DaveNay (Nov 25, 2012)

LED is several times more efficient than incandescent, but it still is no where near 100%. I think they are somewhere in the 25%-35% range. This still means 65% or more of the power consumed is turned to heat.

Incandescent bulbs however are in the 8%-15% efficient range.


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## davebrik (Nov 18, 2012)

Despite the higher cost, these LED bublbs are more power efficient and offer lifespan more than 30000 hours, but it reduces if LEDs operate at a higher temperatures than specfied. That's why they have heat dissipation elements like heatsinks and cooler fins on them. Compact fluorescents offer about 8,000 hours of work. LEDs are also mercury free which is better to environment. I hope we will see further improvements in this technology.


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## oregon_prepper (Nov 16, 2010)

First, congratulations, on trying out new technology!

I want to do a series here on some of my thoughts on this, but first your issue!

I have been doing study on LED technology for about Ten Years now, along with off grid/cross grid living. The most recent changes in LED lighting is as you have found out, hotter than one would think, and that is in regards to heat, not color rating. There is a difference in temperature of the fixture, or lamp, and its Kelvin color output, also some times labeled as a "heat" (cool white, or 'warm', as examples).

The reason they are hotter, is a basic change from either Single LED Bulbs, or Multi-Bulbs, which were once wired with external circuits, to being placed upon a "chip" and having an internal "circuit" to make it both more powerful, and efficient, at the same time. LED lighting comes from a very Unique type of diode construction, and its end product ~LIGHT~ is different than what diodes usually provide a user, hence, you are seeing circuitry in a different method, than older LED technology!

Your lamp needs more Air around it, so it can drive off the heat, which is currently (no pun intended) confined in the lamp your bulb was installed into.

Now, please understand, unless your into touching the lamp 'shade', (to adjust where it shines "best"), you are in no serious danger from its heat, other than the confined heat WILL shorten the life of the bulb.

Those heat fins are meant to dissipate the heat, just like the heat fins fins on a desk top computers CPU, and for the same reason, efficiency!

In fact, not to go to far off the topic, but PV panels are also affected by Excess heat, they work Best, on clear cooler days, than clear hotter or even warmer days.

You have no fear of catching anything on fire, versus an Edison style (filament) bulb, but you *will* benefit from providing more air movement over those fins, or changing that bulb to another location. It is the inability for the air to leave/move that makes it hotter, with air movement, the bulb will run cooler, but only by a small measure of difference. that the bulb HAS fins equates to "I am a heat producing bulb".

FYI, Home Depot, my local big box type store has a huge selection of LED bulbs, at a reasonable pricing, both in 12 VDC & 120 V AC power options.

You will find there, newer style LED bulbs, enclosed within a Plastic "bulb" looking more like the older Edison Bulbs. *These will have the proper Kelvin & lumen output*, for *reading*, or _general purpose lighting_ needs, *Without Excess Heat being given off*.

'Batteries Plus' stores, also have a small selection of *LED* AC & DC bulbs, at 120 & 12 volt power consumption.

I have no financial interest in any store(s) I mention, I am only a dedicated LED light user! (I abhor florescent lights).

One last thing, you can and will find 12 Volt AC/DC bulbs, that can use Both current styles. often used for exterior accent lighting, I will be doing a post or two on them, later!

I do hope this helps your needs,


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## Jim-mi (May 15, 2002)

This heat you talk of is all from the built in "power supply" . . . . . .To change the 120 vac down to a DC voltage.

One bulb I have, I left on for over 3 years . . It was never warmer than a couple degrees above room temp.......never.......
Why . . because it is powered by 12vdc...........

(it still works just fine . .I'm just not using it as a night lite any more.)

That heat issue bothers me. . . . .
If there is that much heat it surely will decrease its life........

Thanks for the info...
Think I will stick to the 12 vdc bulbs..........


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## oregon_prepper (Nov 16, 2010)

Jim-mi said:


> This heat you talk of is all from the built in "power supply" . . . . . .To change the 120 vac down to a DC voltage.


Partly correct, partly incorrect. It is the Style of the specific LED, commonly called CREE with an added designator number, *CREE being a class of intense output LED 'bulb' or light provider*. CREE's are all made in SMD style, that is *Surface Mounted Diode*, that provides more milliamp's in, due to the copper sheet of the circuit boards being used as heat sinking, as well as no wire leads out of the LED, which would be a poor method of heat sinking. 

The reduction of Voltage can be handled straight across via power resistors mated to the mA needs of the light source.

As I read your post, I immediately touched the surface of a 120 VAC LED, I use it as a reading lamp, _a similar bulb is used on my Band Saw, for specific area light needs_. The bulb "looks like" an Edison Bulb (filament) but its PLASTIC globe has such little warmth as to be considered negligible. 

It has Multiple SMD's but none are High Powered Cree's, which typically use a full Watt or more of power!



> One bulb I have, I left on for over 3 years . . It was never warmer than a couple degrees above room temp.......never.......
> Why . . because it is powered by 12vdc...........
> 
> (it still works just fine . .I'm just not using it as a night lite any more.)


very little Lumen output in a night light, regardless of power source, is there?



> That heat issue bothers me. . . . .
> 
> If there is that much heat it surely will decrease its life........
> 
> ...


I agree with this, only to the extent that I make my own 12 Volt power!, I used the term ~cross grid~ in my post, for folks like me who use both concepts!

While I have Utility Company AC, I use it responsibly, in my opinion.

In this post, we are discussing LIGHT's. Edison Lights produce Light, by first creating Heat. IF you do not desire the heat, it is a poor design!

On my Band Saw I have a mounted 12 Volt 18AmpHour Gel-Cell battery. It powers Three things:

1. a 3/4'' diameter High Lumen LED, it spotlights the cutting area, just a three inch diameter, ultra bright spot of light! A switch for turning it on and off is at close reach. After a fifteen minute use, you would not wish to touch this unit, in fact, I have it mounted in a very nice Oak mounting, which is mounted to the Saw guide, so when I cut thicker material, the bulb is lifted per need, the wood also provides insulation from the heat! the bulb is a single unit CREE, but an unknown model of CREE.

2. a 12 Volt Computer Fan, very silent, but provides me with a flow of air, to keep dust moving away from my eyes. 

3. A fan assisted Respirator, to provide good air flow while filtering my air for breathing!

But I always have that above mentioned 120 Volt LED light *ON*, as a general area light, for my Band saw area needs. It has NO heat output, which would bother me, due to its location, close above my head.

In todays technology, we can ~choose~ our products per needs in USE and not by what older technology provided us, regardless of design factors.

That is true ~Cross Grid~ living.

BTW, that band saw spot light, when aimed from "table height" UP, will light the whole ceiling, with both direct, and ambient (Bounced) light, (in an average sized room). I use one for that purpose, instead of Utility Board provided electric lights, when it is Storming outside, because our Rural Electric Company looses power quite often, that way, I am prepared ahead of power outage for power loss!

It is also produced as an 12 Volt AC/DC unit, for garden lighting often uses 12 Volt AC, for limited voltage drop while its wires are far from the power source.

I do hope that helps.


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## Jim-mi (May 15, 2002)

I was not talking about a single little LED night light . .

The bulb I mentioned has at least 25 LEDS . . .and would serve well as a reading / task light over my desk.

. I aimed the fixture at the ceiling on purpose to give a whole lot of "night light"


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