LED lighting question

[crunkzilla]

Anyone here have recessed LED lighting? Would like to know if yours are hot to the touch when on.

Bought the following http://www.amazon.com/Lightkiwi-PAR3...pr_product_top

and noticed that the heatsink is very hot and can barely keep my fingers on it when operating. Previuous flood lights that were in the can were listed as 85W 130Volts, while the new LED ones are listed as 14w 120volts.

Im a little concerned about the heat produced because I have other LED lights that are regular light-bulb shaped that are cool to the touch when operating.

 

[Greenman]

They get hot, that's why they have that big heat sink on them.
I wouldn't worry about it, the can should have a thermal switch in it.

 

[shortylickens]

That just happens to be the one I have. It does get a little warm, but since its recessed its not like I can tell. Never seems to cause any problems. My mom doesnt like the cool white light, but the halogens she had before were drawing WAY too much current.

 

[Jeff7]

Incandescent: The filament gets up to a few thousand degrees, which is what makes it glow in the visible spectrum. The idea then is to keep that heat in there, so it doesn't incinerate everything around it.

LEDs: The die shouldn't get too hot. Maybe up to boiling. Lower is better. So that heat needs to be pulled away from the emitter as effectively as possible - quite the opposite of what incandescent lighting needed. If the heatsink is hot, and the entire thing isn't on fire^_^, that's one way to see that the design is doing a decent job of getting the heat from the LEDs into the heatsink to be dissipated into the air.

LED lights that are cool to the touch may be rated for much lower power usage, or they might have poor thermal design, meaning the LED dies will run hotter, and will likely begin to experience diminished output more quickly.

That just happens to be the one I have. It does get a little warm, but since its recessed its not like I can tell. Never seems to cause any problems. My mom doesnt like the cool white light, but the halogens she had before were drawing WAY too much current.

LED lighting manufacturers like to use cool white emitters because the lumen ratings are higher, and bigger numbers make things easier to sell. White LEDs use a blue emitter, and then pass that through a phosphor coating. Some of the blue gets absorbed and re-emitted up in the yellow range; your eye sees the resulting mixture as white light. If more of the blue is simply passed through, it's more efficient in terms of total light transmission, but the light looks more blue/cool. I've seen white LEDs at the 2700K color temperature, which should be right in line with an incandescent bulb.

 

[olds]

Never used LED lights, I would assume they run cooler than a regular light.
Was watching a home improvement show a while back where the homeowner had insulated over the top of the can lights that he installed. The insulation was scorched. He's lucky he didn't start a fire.

 

[harrkev]

Old-fashioned bulbs put out a LOT of infra-red light, so they are pretty inefficient. The infra-red, however, spreads out, so the "wasted" energy goes all over the room.

LED lights are more efficient, but no IR light at all. Any inefficiencies show up as heat at the die -- so you need the huge heat sink. LEDs still use less energy, is it just that it has a harder time getting rid of the waste.

 

[Mixolydian]

I have recessed LEDs in one room, made by Cree. They barely get warm to the touch.

 

[edro]

If you can't hold your finger on it for more than 5sec., it is likely over 140°F (60°C).
That is pretty warm, but not nearly hot enough to ignite anything.

Those LEDs are cheap Chinese LEDs, so the life of 30,000 hours doesn't tell me much.
If they were decent brand (Lumileds, Cree, etc), a 30,000 hour life would indicate they are being driven very hard and very hot.

I wouldn't worry about it.
There is nothing in a recessed can that can catch fire near the lamp base/reflector.

 

[Sho'Nuff]

That just happens to be the one I have. It does get a little warm, but since its recessed its not like I can tell. Never seems to cause any problems. My mom doesnt like the cool white light, but the halogens she had before were drawing WAY too much current.

They make warm LED lights now.

My local home depot had these in stock for 16 bucks a pop and a 5 dollar instant rebate.

http://www.amazon.com/Philips-409904...ight+bulb+warm

 

[SandEagle]

i'll be mounting an LED work lightbar on my truck soon. It's got 6000+ lumen output with 9-24 VDC and current consumption < 4 amps.

 

[edro]

"Warm" color temperature LED lights are starting to come out because efficiency is rising.
To make LED light warm, you need to dope with more phosphor. Natural LED light is blue. (on most modern LEDs)
Adding more phosphor reduces the light output. Since LEDs are more efficient now, they can add more phosphor and still get enough light out to be useful.

Philips remote phosphor lamps (look yellow when unlit) are just a different method of mixing the phosphor layer with the raw blue light from the LED die.
There isn't much of an efficiency benefit to remote phosphor... it's just a different manufacturing method.

 

[Jeff7]

"Warm" color temperature LED lights are starting to come out because efficiency is rising.
To make LED light warm, you need to dope with more phosphor. Natural LED light is blue. (on most modern LEDs)
Adding more phosphor reduces the light output. Since LEDs are more efficient now, they can add more phosphor and still get enough light out to be useful.

Philips remote phosphor lamps (look yellow when unlit) are just a different method of mixing the phosphor layer with the raw blue light from the LED die.
There isn't much of an efficiency benefit to remote phosphor... it's just a different manufacturing method.

One benefit is that it makes it flexible in terms of the light source: You don't need a "white LED." You just need some kind of blue LED underneath the remote phosphor. It can be a Rebel, Rebel ES, something by Cree, something from Everlight...take your pick. Put a bright royal blue LED source under there, let it excite the phosphor, test it, ship it.

 

[Mark R]

One benefit is that it makes it flexible in terms of the light source: You don't need a "white LED." You just need some kind of blue LED underneath the remote phosphor. It can be a Rebel, Rebel ES, something by Cree, something from Everlight...take your pick. Put a bright royal blue LED source under there, let it excite the phosphor, test it, ship it.

The other advantage of remote phosphor is that it provides strong diffusion without much additional light loss - so it's slightly more efficient that using white LEDs and a separate diffuser.

This is particularly important because white LEDs, even the 2700K ones, have a terrible spectrum which is severely deficient in red (and also cyan, but this isn't really a big deal). This gives poor colour rendering of skin tones giving an anemic appearance and grey skin coloration. To get around this, high-end LED lamps also include red LEDs - but this needs strong diffusion to avoid uneven color in the beam. Philips use their remote phosphor to good effect in their "red-enhanced" lamps.

 

[werepossum]

Anyone here have recessed LED lighting? Would like to know if yours are hot to the touch when on.

Bought the following http://www.amazon.com/Lightkiwi-PAR3...pr_product_top

and noticed that the heatsink is very hot and can barely keep my fingers on it when operating. Previuous flood lights that were in the can were listed as 85W 130Volts, while the new LED ones are listed as 14w 120volts.

Im a little concerned about the heat produced because I have other LED lights that are regular light-bulb shaped that are cool to the touch when operating.

Pick up a Kill-A-Watt meter, put the lamp in a, um, lamp, and measure its wattage. Some cheaper brands are highly inefficient, and you might well find that the 14W is the power consumed by the LEDs, not the lamp itself which includes driver losses. Not all LEDs are efficient. A couple years ago when looking at fixtures to specify I saw one with no easily accessible information, and when I finally got efficacy figures it was 10 lumens per watt - about half the efficiency of the best halogen lamps! It's still not uncommon to see major lighting companies pushing products under 40 lumens/watt. The specs on this one look pretty good, although I'm not familiar with this brand, but when the DOE tested LED lamps a few years back almost none of them performed as specified.

An LED should never get too hot to comfortably touch. Is there enough room around the heat sink for air to flow? This looks like a PAR-30S (short neck) rather than a true PAR-30, although that's very hard to tell from photographs, and if your downlight is designed for PAR-30 or even PAR-38 only you may not have sufficient air flow. In that case the heat is being trapped, which will degrade the life of your LEDs and especially your driver. But as Edro indicates, likely they are simply overdriving the drivers and skimping on the aluminum. Especially if they are using older generation LEDs and drivers, it's difficult to get enough aluminum and air flow within the envelope of the lamp.

 

[Sho'Nuff]

"Warm" color temperature LED lights are starting to come out because efficiency is rising.
To make LED light warm, you need to dope with more phosphor. Natural LED light is blue. (on most modern LEDs)
Adding more phosphor reduces the light output. Since LEDs are more efficient now, they can add more phosphor and still get enough light out to be useful.

Philips remote phosphor lamps (look yellow when unlit) are just a different method of mixing the phosphor layer with the raw blue light from the LED die.
There isn't much of an efficiency benefit to remote phosphor... it's just a different manufacturing method.

Just to clarify, when you say "efficiency" you are referring to conversion efficiency, right? And when you say "dope with more phosphor," you mean that higher concentrations of phosphor are used in the phosphor conversion layer (regardless of whether remote conversion or chip layer conversion is used), not that you are "doping" the phosphor more (e.g., with higher amounts of a dopant such as Ce), right?

Remote conversion does open some interesting backscattering issues. Can be a benefit or a curse, depending on the lamp configuration. At least from a luminous efficacy standpoint.

 

[RossMAN]

They make warm LED lights now.

My local home depot had these in stock for 16 bucks a pop and a 5 dollar instant rebate.

http://www.amazon.com/Philips-409904...ight+bulb+warm

Thanks for the tip and link, I'll be visiting HD tomorrow. Do you own these?

Is the light focused? Looking for a decent replacement for our CFL recessed lights.

 

[Sho'Nuff]

Thanks for the tip and link, I'll be visiting HD tomorrow. Do you own these?

Is the light focused? Looking for a decent replacement for our CFL recessed lights.

I own one of them, which I use in a recessed lighting canister in my kitchen. It is a vast improvement over the LED light it replaced, which made my kitchen look like a morgue.

The bulb itself is a bit odd to look at, so I would not use it in a location where it would be exposed. The light does diffuse fairly well, though it is not as good as a CFL, halogen, or traditional bulb.

One thing that irritates me is the lumen ratings on LED bulb packaging are not accurate. 800 lumens from a LED bulb does not look anywhere near as bright to me as 800 from a halogen/standard bulb.

 

[crunkzilla]

Pick up a Kill-A-Watt meter, put the lamp in a, um, lamp, and measure its wattage. Some cheaper brands are highly inefficient, and you might well find that the 14W is the power consumed by the LEDs, not the lamp itself which includes driver losses. Not all LEDs are efficient. A couple years ago when looking at fixtures to specify I saw one with no easily accessible information, and when I finally got efficacy figures it was 10 lumens per watt - about half the efficiency of the best halogen lamps! It's still not uncommon to see major lighting companies pushing products under 40 lumens/watt. The specs on this one look pretty good, although I'm not familiar with this brand, but when the DOE tested LED lamps a few years back almost none of them performed as specified.

An LED should never get too hot to comfortably touch. Is there enough room around the heat sink for air to flow? This looks like a PAR-30S (short neck) rather than a true PAR-30, although that's very hard to tell from photographs, and if your downlight is designed for PAR-30 or even PAR-38 only you may not have sufficient air flow. In that case the heat is being trapped, which will degrade the life of your LEDs and especially your driver. But as Edro indicates, likely they are simply overdriving the drivers and skimping on the aluminum. Especially if they are using older generation LEDs and drivers, it's difficult to get enough aluminum and air flow within the envelope of the lamp.

The ones Im using in the cans are on for about 3-4 hrs at night and get really hot and can feel the heat off it if I put my hand near it. The old incadescents bulbs that were in there used to shutoff when it got too hot, so hopefully these LED ones do the same thing.

 

[Squisher]

Thanks for the tip and link, I'll be visiting HD tomorrow. Do you own these?

Is the light focused? Looking for a decent replacement for our CFL recessed lights.

I have one in a table lamp, they are a replacement for normal incandescent light bulbs. So, no, they are not focused.

I did not get the instant rebate. If they're going to start giving these out for $10 then I want to pick up more.

 

[Sho'Nuff]

I have one in a table lamp, they are a replacement for normal incandescent light bulbs. So, no, they are not focused.

I did not get the instant rebate. If they're going to start giving these out for $10 then I want to pick up more.

The instant rebate was offered by New Hampshire power companies. Might not be available in your area.

 

[RossMAN]

The instant rebate was offered by New Hampshire power companies. Might not be available in your area.

If HomeDepot.com prices are accurate in my area they're still just under $40 and I doubt any local utility incentives would be more than $5 - $8 off.

Waiting for these to hit $15-ish before I buy a few.

 

[torpid]

I've been researching LEDs as recessed bulbs and I'm seeing a fair number of people say that it's probably not a great idea unless your housing has been fitted for LED because the heat is made to go towards the housing and not outwards. Thus, the light is likely to last way less long than you'd want from an expensive LED because, even with a heat sink, it's still accumulating in an area you don't want it to and not able to escape easily.

Anyone seen this or is this more of an urban myth type of thing?

 

[Squisher]

If HomeDepot.com prices are accurate in my area they're still just under $40 and I doubt any local utility incentives would be more than $5 - $8 off.

Waiting for these to hit $15-ish before I buy a few.

The 12.5 watt LED which is equivalent to a 60 watt incandescent is ~$15 at Home Dept, but then the prices jump through the roof. I think the 15 watt LED (75 watt) is ~$40.

Right now the best bang for the buck is having fixtures that use multiple bulbs.

 

[edro]

I've been researching LEDs as recessed bulbs and I'm seeing a fair number of people say that it's probably not a great idea unless your housing has been fitted for LED because the heat is made to go towards the housing and not outwards. Thus, the light is likely to last way less long than you'd want from an expensive LED because, even with a heat sink, it's still accumulating in an area you don't want it to and not able to escape easily.

Anyone seen this or is this more of an urban myth type of thing?

Anything UL or CSA listed is thermally tested in the orientation and housing it is expected to see (worst case) in the field.
The LED junction temperature, thermally stabilized in these tests, is how the life data is calculated.
Good companies do this properly.
Cheap companies lie, or simply state a generic number such as 50,000 hours life!

If you see a Lighting Facts label on the product, it is probably a reputable company and their data has been checked.

 

[Fanatical Meat]

I have a 40 watt equivalent led running 24/7 for 1 year now. The bulb is always cool to touch. Before anyone asks it used for the cat so he can poop without missing his litter box.