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 Post subject: Home Depot led light bulb
PostPosted: Jun Wed 12, 2013 4:55 am 
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Location: saginaw, mi USA
Bought 4 60 watt equivalent led dimmable bulbs from HD at $12.97 ea. Puts out a nice equivalent light. 800 lumens @ 9.5 watts. My question is there is considerable heat put out on the heatsink next to the screw in base. How much of that is being taken from the 9.5 watts. Is there any way to determine this or am I being anal. I can measure the temp.

Keith


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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Wed 12, 2013 5:11 am 
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Our house will be 15 years old in a few days. We still have many of the original light bulbs. How can these tremendously expensive new CFL & LED ones ever make sense? I just replaced one of the originals, a 65 watt flood light in our downstairs corridor. I got a laugh when I saw that the box of new ones (regular incandescent) stated they are good for two years.

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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Wed 12, 2013 6:42 am 
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Location: Perrysburg, OH, U.S.A.
Unfortunately, not easily.

There are three ways I can think of to figure the power lost to heat. First would be to measure the temperature as you alluded to. You would need to measure the ambient air temperature and the bulb case temperature. BUT, you would need to know thermal resistance of the bulb case to air, Rca, at the point at which you measured the case temperature. You don't know Rca, so that's out.

Second, you could convert the light output of 800 lumens to watts of light output. This is a hairy conversion at best, converting a photometric quantity (lumens) to a radiometric quantity (watts) and is not for the faint hearted. You would need the solid angle of dispersion, the spectra of the light (not constant with dispersion angle), various correction factors for the human eye response and THEN solve a triple spherical integral.

The third method has the greatest chance of success. Find an insulating liquid (transformer oil?) with a known specific heat capacity, C (in units of Joules/kg-K). Find an insulated container big enough to easily hold the LED lamp and a socket wired to a plug. The bigger the container, the better here, because you want the insulating liquid to be the greater part of the total mass. Weigh the insulated container with the LED lamp and its socket.

Measure out enough insulating liquid to completely immerse the lamp and socket and weigh everything again. The difference in measured weights will be the mass of the insulating liquid, M. (Yes, for the purists, it's just the weight of the liquid and not the mass, but here it won't matter.) If the M is in pounds, multiply it by 2.2 to find the weight in kilograms. Wait at least an hour and measure the temperature of the insulating liquid. Call this Ts. Plug in the lamp and wait an hour or more (more if you have a large amount of liquid). Record this length of time in seconds. Call this t. Measure the temperature of the insulating liquid again. Call this Te. The temperature difference, Td = Te - Ts, is rise due to the heat lost in the lamp. If the temperatures are measured in degrees Fahrenheit, simply multiply Td by 5/9 to find the difference in degrees Celsius.

Finally, find the power lost to heat: W, watts = C x M x Td / t

John

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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Wed 12, 2013 12:35 pm 
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Definition of the Lumen here:
http://en.wikipedia.org/wiki/Lumen_%28unit%29

Note the part about lumens per watt when the energy is all at the peak of the eye response (555 nm): 683 lumens / watt. LEDs have the potential for high efficency because they can put all the light** at visible wavelengths.

Start with the part about "60-watt equivalent": Using that and the output of 800 lumens, we see that the incandescent bulb would be doing 800/60 = 13.33 lumens/watt.

An "ideal" bulb will use just over 1 watts to get 800 lumens (using the number from wikipedia: 800/683 = 1.3 watts. This implies that your LED bulb is putting 9.5 - 1.3 = 8.2 watts into heat. A CFL is (i think) something like 14 watts to get 800 lumens, but there the excess power does not all go to heat in the lamp (it goes to non-visible light**)

How does this relate to the original question, you might ask?........If you could measure the total radiated power, you could subtract that from the AC input power, and you'd have the dissapation in the power conversion between AC line and the actual lamp (LED)


**I'm using "light" to mean radiated energy---a bit imprecise since light is really defined as what we can see.

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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Wed 12, 2013 12:37 pm 
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FStephenMasek wrote:
Our house will be 15 years old in a few days. We still have many of the original light bulbs. How can these tremendously expensive new CFL & LED ones ever make sense?

In principle, is it not a good thing to have higher efficiency in lighting? It is good to use less energy----I think maybe the real issue is who pays.......

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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Wed 12, 2013 2:09 pm 
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I would just get a Kill‑A‑Watt meter and plug the old and new lamp into it and see what they draw. That's what counts as far as savings. If the lamp says it draws 9.5 watts then that's what it should draw. If the heat it produces is adding to that 9.5 then they are fibbing about the amount of savings. Your eyesight will decide if the new one is enough light.

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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Wed 12, 2013 4:35 pm 
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Location: alameda,CA
I'd like to get some LED lights, but more for the outside of the house. Its just that I can't seem to find any that can be used in fully enclosed fixtures as it says on all the packages I've read not to use them for those.


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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Wed 12, 2013 4:54 pm 
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Location: La Porte, IN, USA
I have been using several different brands (purchased on sale at Lowes and Menards) of LED bulbs for several years.
I would call the results nothing less than excellent. Out of perhaps 24 bulbs, I have had one (1) failure. It failed within a week of purchase, and was returned to Menards for a refund.
On sale, all these bulbs were either $8.99 or $9.99, and all are Dimmable (I have a number of dimmers throughout the house).
I measured actual current/wattage on several and they were indeed as advertised.
I have two on dusk-to-dawn outdoors on the garage and one inside the garage for over a year.
I have two more on 24/7 in the basement for about a year.
The light from a 10 watt LED is easily eqiuvalent to that from a 60 watt incandescent bulb, though slightly directional.
Because my wife is sensitive to color temperature when doing her make-up, I have had to search for "Warm white" bulbs. They are available, on sale.
These things are the future, in my opinion.

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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Thu 13, 2013 12:22 am 
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Location: SOUTHLAKE, TX, USA
I have a 100W incandescent bulb in the ceiling of our shower. It has been in service since 1983!!!
BOB


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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Thu 13, 2013 2:11 am 
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Location: Mission Viejo, southern California
pixellany wrote:
FStephenMasek wrote:
Our house will be 15 years old in a few days. We still have many of the original light bulbs. How can these tremendously expensive new CFL & LED ones ever make sense?

In principle, is it not a good thing to have higher efficiency in lighting? It is good to use less energy----I think maybe the real issue is who pays.......
Money is a handy thing, as it allows us to easily compare many things. I pay, and the incandescent costs less. The power company charges show all of tbsir costs. I could have an engine as efficient as the best racing engines on my vehicle, but the cost would far exceed the fuel savings. We only spend $70 per month on electricity, and have two offices with office machines at home.

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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Thu 13, 2013 2:33 am 
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I bought one of these a few days ago to try out. The light is a little on the blue side for my taste but it is bright.

The ceiling fixture I took it out of had two 60w bulbs in it, the nut holding the glass on was so hot I nearly burned my fingers taking the cover off, if nothing else I should save some energy not having that much heat dissipating into the house, if I buy a second one to put in this fixture that'll bump it up to 18w compared to the 120 it was using. 8)

At work I use an LED Flashlight, that thing totally makes an incandescent Flashlight obsolete!
The Bulb is far brighter (though more focused) it never burns out even if you drop it and the battery lasts for days on one charge.
Same thing with the rechargeable LED Drop Lights, the only drop light I've ever had that is actually worth a damn. Incandescents are always burning out or breaking, not to mention hot! and the Fluorescent type are always breaking or the fixture they are in falls apart, they are also big and awkward.


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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Thu 13, 2013 3:35 am 
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I said this in another thread and I'll say it again -- different bulbs for different purposes. There are certain instnaces where only an incandescent will do. However CFL's and LED's have their merit, and I'm sure as time goes by you will see more and more of these. Plus, as I've said in the past, as the LED's go down in price and up in popularity, the concept of the removable light bulb will be replaced by light fixtures with built-in LED's. Imagine a chandelier with hundreds of tiny lights instead of three or four bulbs. Imagine the creativity in bathroom fixtures or outdoor lighting. Just like plug-in tubes were replaced with soldered-in transistors, I think you'll see more and more permanent solid state lamps.

I'll also agree it's a bit silly to spend big money on bulbs to replace those that have lasted 25 years. BUT -- most likely the reason they lasted so long is that they're rarely used. Closet lamps for example. I've got a hallway light that doesn't see much use. But suppose they DO burn out -- it's a judgement call as to whether you want to replace it with another conventional lamp or a more modern type. If it's really hard to reach, an LED could be the ticket, just so you'll never have to deal with replacing it again.

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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Thu 13, 2013 12:02 pm 
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Those LED flashlights work great. I now only buy the metal ones with one high intensity LED. I have a five D cell mag light which is about a foot long and cost $20 without the batteries. A $5 (with batteries) three double A high intensity single LED flashlight blows it away and is only six inches long. I just bought two small single AA high intensity flashlights (with battery) for $2 each and they are brighter than the five D cell Mag light. They are going in the tool boxes.

Just a note - Don't use Duracells in any of them. Duracells leak more than any other brand of battery I've ever used. I don't use them in anything anymore that might sit unused for awhile.

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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Thu 13, 2013 1:17 pm 
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pixellany wrote:
In principle, is it not a good thing to have higher efficiency in lighting?

Not at the expense of fire danger (CFL, ask me how I know) or RFI emissions (LED). All this hype over LED bulbs is nice but the fact is the RFI emitted by most (all?) is unacceptable. I have tried several in the lighting above the workbench and every single bulb interfered with nearby receivers. I finally moved the bulbs to the basement. It seems that nothing coming from China is being tested for RFI. I was disappointed to see that Consumer Reports recent review of LED bulbs did not even include RFI in the testing. That omission makes the review worthless, IMHO.

Larry

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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Thu 13, 2013 1:40 pm 
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Location: 48314
FStephenMasek wrote:
pixellany wrote:
FStephenMasek wrote:
Our house will be 15 years old in a few days. We still have many of the original light bulbs. How can these tremendously expensive new CFL & LED ones ever make sense?

In principle, is it not a good thing to have higher efficiency in lighting? It is good to use less energy----I think maybe the real issue is who pays.......
Money is a handy thing, as it allows us to easily compare many things. I pay, and the incandescent costs less. The power company charges show all of tbsir costs. I could have an engine as efficient as the best racing engines on my vehicle, but the cost would far exceed the fuel savings. We only spend $70 per month on electricity, and have two offices with office machines at home.


Using the example of a table lamp that you use for 4 hours a night with a 60W bulb, that works out to 87.6kWH/year for the incandescent and 13.1kWH.year for the LED. At .15/kWH that is a savings of $11.17/year meaning the LED is paid off in less than a year at which point you are now saving that much each year, for each LED bulb used.

I swapped out two 60W dust-to-dawn lamps on my garage a few years ago. They are on an average of 12hrs/day. At $9.99 they paid for themselves in 100 days and I am now saving $67/year on just those two bulbs.

Where LED's don't make sense are in applications that are rarely used like a closet since the payback period would be much to long.

Darryl


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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Thu 13, 2013 2:17 pm 
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Location: Biloxi, MS
I bought one LED 40W (equivalent) bulb just to see how long it'll last. I think the packaging said it should last 23 years. We'll see about that, but I'm not too confident. It's above a vanity in our bathroom and gets about 2-3 hours use daily.

On the subject of LED flashlights, I can't say enough about how great these things are, particularly the type that uses the CREE LED "bulb". I have low vision in dark and near-dark situations so I rely on it and usually keep it handy. I bought a cheap one from Amazon and literally burnt the LED from heavy use. It literally turned brown, resulting in a yellowed and diminished lumen output. I went back to Amazon and splurged on a $60 model (crazy for a flashlight, I know) and it's been fantastic, and it'll run for 2-3 months off of 2 AA Energizer Lithium batteries. I use it a lot, including up-close electronic repair work. It's so bright I can light up my whole back yard at night, about a half acre.


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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Thu 13, 2013 6:25 pm 
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I didn't think this was going to generate so much conversation. I am very happy so far with the Home Depot bought bulbs and as stated by a prior post about Cree manufactured flashlights these are also Cree. They emit a light very comparable to a incandescent bulb, even looking at the bulb directly it appears to be a filament in a frosted bulb. I will need to experiment on the actual wattage usage. As in my original question/thought was about how much wattage went to heat generated and appreciate the answers and opinions expressed. I am thinking that since the LEDs in the bulb pull very little that the bulk of the 9.5 watts is going to heat. The electronics in the base must be the true source of the heat.

Keith


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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Thu 13, 2013 7:42 pm 
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Location: Dunnellon FL USA
I haven't brought myself to buying any LED lamp-type bulbs, mostly due to their very high price. My home is lit with a mix of CFLs, incandescent and straight fluourescent lamps, and we are happy with the results. We also added two Sola tube skylights that both us are still, after 10 years, trying to turn off when we leave the room. So far, the only leds in the house are the little red indicators on various electronic devices.

That said, two weeks ago I added 4 high intensity LED driving lights to my Gold Wing motorcycle. All I can say is "WOW!" These things are 10 watts each, about an inch across, mounted in custom made reflector assemblies, and project a pure white 6000k light down the road. My first comment was "The days of incandescent lamps are numbered." The installation was forced by a senior moment I experienced when I inadvertantly rode over one of those concrete bumpers at the end of a parking slot. Smashed the bottom of the lower cowl that contained the original incandescent driving lights. I bought a replacement cowl on EBay and had a shop about 100 miles south (Clermont FL) build the new set. Wow. The new units are far more effective than the incandescents, lighting up more of the roadway and making us more visible (less hit). Plus I can sell the old system to some other Gold Winger at our chapter's next yard sale.

Were they inexpensive? Definitely not, not with having to buy a new cowling, and have the custom made fixtures installed. Also these after market units were less expensive than having a dealer do the repair. Were they worth it? Absolutely, as being seen and thus being less hit is very much less expensive, and less painful.

Life is good..now if I could only get a cellphone jammer added to the bike.....
Ride safe..
John L


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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Thu 13, 2013 8:22 pm 
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Since we're onto 12V automotive LEDs ;) I've also swapped out the incandescent "peanut" #193 bulbs in the footwells, mirror/map and dome lights in my truck. It's so darned bright in there it's almost daytime. They're still pricey, but with the way LEDs are finding their way into replacing everything incandescent, they won't be expensive for long.


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 Post subject: Re: Home Depot led light bulb
PostPosted: Jun Thu 13, 2013 11:58 pm 
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I replaced all the incandescent lamps with LEDs in my camper last year to conserve the batteries when boon docking. I can now have 8 or 9 of them on at once and they still draw less than just one of the incandescents.

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