LEDs

20 Watts? Is that the power to run it?

I have seen 3 Watt LEDs that provide enough candela to read by.

Can have a photo & specification sheet? at least make & model numbers?

here are the spc.LU 1400-1600 F.Volt 12v- power 20W light angle 140deg and here is a pic.

Got it! The heat is from LED power supply; LED are normally cool; Lessons learned - Do not go blindly with LED lamps! They give excellent service life but not the power supply that drives them; LED are cool but not their driver circuits.

Published specifications for a bare LED emitter are "nominal" -- the actual power usage is entirely dependent on the efficiency of the driver electronics. That also applies to the light output. Published specs from even highly respected manufacturers have been known to be "optimistic".

I've found DIY forums with excellent information from hobbyists/experimenters. There are a surprising number of folks building high-power LED flashlights. They are experts at maximizing lumens per watt, and handling heat dissipation.

http://www.candlepowerforums.com/

http://www.instructables.com/

http://www.hackaday.com/

The led is on a 5 inch long by 1 inch wide heat sink which is attached to a metal light housing.Even with all that the housing get a little warm, Not hot.So to me the led's wast too much by means of heat that is energy. I know that their not prefected yet, and everyone is trying to make money off them.

As long as the design is not a bad one, LEDs use far less power than any other lighting technology.

As long as this thread is going, I won't start a new one.

I've been looking at LEDs for my lighting project. Why are they so incredibly expensive?

I'm hesitant to go with incandescents, because with the sweeping power that the EPA has been granted, I can see a real possibility of them being banned in the next ten years. Plus, I'm always interested in reducing my power bill.

CFLs have been a major disappointment. I don't like the color of the light, they can't be dimmed, and they've cheapened the quality of them to the point that they're toast within two years.

The only other choice I see is the small halogen bulbs.

Any thoughts?

The problem is two-fold.

One, the manufacturing process is still expensive to make the LEDs so that they are both bright and robust.

Two, the NRE (Non-Recuring Engineering) costs are/were high and it will take some time to pay that cost off.

The idea is that it will pay off because the sheer volume will make up for the big costs up front.

A third, but less important reason is that there is already a market embracing them despite costs. That market is aircraft, safety (i.e., stop lights), and obstruction lighting. Even though the up-front cost is higher than a standard bulb, the long term replacement and maintenance cycles are much cheaper. In the end it saves money - big money.

LEDs have revolutionized the aircraft industry. Modern lamps are now all LED. That includes interior lighting and exterior lighting. Those super bright strobes you see on aircraft wings are most likely now LEDs!

Lower power consumption for aircraft translates into lighter wiring harnesses and much longer lamp life.

Personally, I chose LED bulbs to first reduce heat. The extra heat with incandescent lamps is just another waste of air-conditioning money to cool my house in Florida.

My office gets hot and running incandescent bulbs at night just makes it worse.

Lastly, the automotive market is cashing in on these.

They are the best option it seems.

I was looking at the fairly lame selection at Home Depot. I like the amount of light that can be had from very small, unobtrusive recessed ceiling fixtures. Not only can they be dimmed, but the beam can be adjusted from narrow to wide, which is cool.

When the time comes to purchase, I'm sure I can find much better prices on line than at the big box stores.

Thanks

Yes, I am sure you will see some fancier LED systems with adjustable color. Not only can you dial in intensity, but the color of the light, too.

The Boeing Dreamliner does this inside the passenger cabin.

Don't count on Home Depot or Lowes to have the most up to date or inexpensive LED out there for a bit more time. Look to on line stores or directly from MFG to purchase.

LED's still have a ways to go, they are gettiung better and closer to what we require in lighting an area. I use LED's every day at work, just not for lighting an area. For that, I still use T5HO's. Still the best bang for the buck or best Lumen for the buck. And they can be dimmed, although the fixtures are still quite expensive. I gave up on CFL's since they have been mass produced by China. They don't even last 3 months, but now they only cost $2.00 Ea...

Yep, CFLs are junk now. I feel bad every time I throw one away. I know the bulb is still good, it's the components in the base that crap out fast. Now I'm tossing mercury and plastic in the trash.

Another great "green" idea that's backfired. But think of it this way. At least the short lifespan of the bulbs will help the President's darling company, GE, remain profitable. Plus they have been a huge job creator...............................in China.

There's no way it's going to be fluorescents. The wife would never go for it, and I would have to agree. Whatever it is, is going to have to be aesthetically pleasing.

If it's really such a big deal buy a few 100 incandescents

I'm not sure why you think the idea of increased light per watt is a fail?

I haven't had nearly the CFL attrition everyone is complaining about

change is scary, suck it up

GE is every presidents darling & have been for 100 years

I actually like saving electricity and running as efficiently as possible. It saves money.

CFLs may work fine in some applications. My basement isn't one of them. They continually burn out. Unfortunately, I think this is more of a quality issue than anything else. They've just become another piece of junk that is churned out by China with the proud GE label on them.

You must have some serious power issues, or just bad luck. The shortest lived CFL I've had was about 5 years old, it was for an outdoor light run on a dusk-dawn lamp even during the cold PA winters. Avg LED have had was about 6 months. LEDs cost twice as much, less light, and died faster. Oh I forget also made in China.

Maybe just bad luck. They don't like it in my basement. Someone told me it may have to do with the on/off cycling.

I have been told that florescent bulbs do not last long if mounted sticking straight down, as might be expected in a basement. If fact, I too have had a lot of them fail in my basement. When mounted in a horizontal position they seem to last much longer. I have had a light mounted as an outside light for several years and it has lasted fine (on all the time).

CFL lamps -

1) don't like on/off cycling - don't use them in halls, baths closets

2) need ventilation - don't put them in a can where the heat is trapped

3) don't do well in the cold - a CFL porch light in Nome, Alaska is a bit stupid

4) do contain very little mercury - if you eat fish once a week you get far more mercury than will come from your lamps

I have yet to change a CFL lamp (except one someone broke) in the past 4 years and I have many, many installed

Yep, they're upside down.

So my next question, is where do I get an "L" shaped screw in adapter to put them in a horizontal position? Sounds like a money maker if it hasn't been invented yet.

Upside down makes no real difference if the heat can escape. I have used them in all orientations with good success.

In a can in the ceiling the heat just builds up - unless it leaks up into the attic.

Although I have no explanation for why, it seems to be the case for me. The upside down ones in the basement are always burning out............plenty of space around them for heat to escape. The sideways ones in my kitchen, that are contained within a ceiling fixture, (more heat), have lasted for years.

And right you are:

All that nonsense about CFL

I have 76 of those in and out the house for years and I do not buy more than 5 replacements a year. And many are cC ** .............................**(cheap Chinese)

Go on Ebay and search for the type of led you want. I have purchased directly from Chinese mfgr.s for about 10% of the cost of obtaining them here through distributors stateside. The only drawback is shipping time can be a few weeks. It's quite easy to build your own custom lighting systems, and you can mix colors to obtain the right color for your setting. As mentioned above, there are many DIY sites devoted to this.

I read somewhere that many incandescent lamps use only 5% of the energy to produce light, the rest goes as heat.......

You forgot automotive and marine applications for LEDs. In short, anywhere that you use DC power LEDs are the obvious choice for cost and battery life. In residential applications where AC is supplied the transformer and rectifier circuit add complexity and cost while decreasing expected life span.

CFL's can't be dimmed?

http://www.amazon.com/Lutron-DVCL-153P-WH-Dimmable-Dimmer-White/dp/B004DZOMKC

or is that just the wireless remote stuff?

Yes, there is a special type that can be dimmed. I actually bought a couple for my stairwell going upstairs, tried them, and returned them the same day. They work alright, but the color is terrible. Just cold white light. I went with regular incandescents.

http://www.amazon.com/Feit-Electric-BPXN50MR16-GU10-120-Volt/dp/B0013G3HWI/ref=sr_1_2?ie=UTF8&qid=1318761253&sr=8-2

as a halogen replacement

to me the fixture [when using CFL's] makes a huge difference on how pleasant the light is, the packages aren't always clear on what color light the bulbs produce

The xenons look like a possible alternative.

I bought some the other day for a track fixture

no chance to put them in yet

the missing wall in the living room seems more important

You too!!!

I just finished wiring and sheetrocking a wall yesterday in the kitchen. Installing a hutch today. It's been bare studs for 8 years. It's a wonder I'm still married.

I keep waiting for that remodel TV show with the big truck to come bail me out. Unfortunately, after watching a couple of episodes, I think I have to die first.

At least you just moved in. You've got a little time before the wife starts going nuts.

we are enjoying the open airy feeling

it's hard to keep the dogs inside though

after the rotten sheetrock was removed, but before I ripped down the rest of the wall

the walls aren't load bearing the old telephone poles hold every thing up

the last owners installed a slab behind [left the form in] which funneled all the water to the wall & under the house. took about 15 years to destroy the area. I'm installing a footer & small curb when the sun comes up

I will never buy another fixer upper. Once this place is done, that's it!

Are you sure that's a dog? Kinda looks like a kangaroo.

italian greyhound/rat terrier

the squirrel population is greatly reduced, he works in tandum with our giant poodle [don't look Kris]

Iggy flushes em, Lucy Kills em

I have Last month, purchased a new 3 BHK Flat. My wife and son decorated every room with LED lamps & CFLs under the false ceiling. I managed one T-5 Florescent lamp in each room. Now my wife & son felt the difference & and rarely use LEDs and CFLs.

Why not use straight fluorescent lamps, 18W and 36W? You can get different temperature (and thus colour) ratings. They last a lot longer than CFL, but use more power and take up more room.

SOME CFLs can be dimmed, color choice is limited but there.....

About dimming, you must read the packet carefully......

For LEDs, top quality power supplies are needed to reduce power loss.....they simply cost more, but I am of the opinion that even with a less than perfect power supply, the overall power usage will still be far less for the same light output.....

Using a 20watt LED for reading is a slight overkill on the part of somebody.....was it the OP?

Correct! I think LEDs should be preferred where just light is required, say gang ways path, etc. Where good illumination is concerned one should not go for LEDs.

Wattage is important. I bought an LED lamp, shaped like a standard incandescent bulb, covered in LEDs, rating 6 watts. The resultant lighting was disappointing. I recommend no less than 12 to 15 Watts in LEDs for adequate illumination over a small area.

As you get older 20 watts may be a good idea for reading small print. Here in Australia, I have to take my new telephone directory (with the extra small print) outside to read it, or use a magnifying glass.

I just bought a 3.8W LED in an MR16 configuration to play with (cost $8). It runs on 12V AC/DC (no external driver - all electronics are in the base). Just for fun I compared it to a standard 14W CFL. At ~250mm distance I measured ~500 LUX from the LED, and ~100 for the CFL. Of course these numbers are crude since the CFL emits light in all directions (most of it doesn't go where I'm looking) while the LED is more of a flood with ~120° cone. The lamp has been on for several hours now and is just barely warm to the touch. So as far as I can tell the LED wins if the power supply or transformer is more than ~20% efficient. The light is 'pleasant' compared with either soft-white or daylight CFLs. The only real drawback I find is that it is painful to look directly at it.

If it gives off less heat energy than an alternative of the same lumens output, then there is a point: greater efficiency. In this case, maybe somewhat better than a CFL, and considerably better than an incandescent; but properly comparable numbers are needed in order to tell.

Sorry, The LED power supply will be ~95% efficient if changing the voltage from 12/24/120/240 to the actual voltage needed. If the LED runs right from, say 12 volts, it will just have a hard wired current limit (to avoid thermal runaway in the LED)

LEDS do make heat, but a lot less than incandescent and somewhat less than conpact fluorescent

www.ledsmagazine.com

LED Efficiency

LED Supply...

I was at IKEA yesterday and was surprised by the large selection of LED "bulbs" that they now have available on their shelves. It's become quite easy to simply unscrew, twist-out or pull-off existing bulbs and replace them with LEDs (well, at least it is over here in Europe).

"incandescent"?? What's that? I've heard that it's something like gathering sticks (or dried animal dung) and lighting a fire in the middle of a room, right?

Incandescent, fluorescent, LED, mercury, sodium, halogen, arc(!)--what a load of piffle. Sunlight, firelight, candlelight...

All flourescents need to be returned to the shop when they are defective to make sure that the mercury does not end up poisoning this world (anymore than it already has!!)

I wonder how a 100W incandescent lamp adjusted with a dimmer to the 60W lumen level would compare to LED's and CFL's as far as heat, life and energy consumption is concerned.

It would generate 60% of the heat that it did when running at full output plus some heat generated by the dimmer.

Very badly I believe as you would be operating the filament colder, so a lower resistance, less "light", more heat!!

You should test it out!!

Good thought, but if he does as he stated and adjusts the light output to match a 60 Watt bulb why would you not expect the same ratio of heat dissipated?

I would expect more energy to be used in heat than light pro rata with a lower voltage, not forgetting the energy wasted in the dimmer either.....

You could drop the light to nothing - black, but still use some power and still have the element too hot to touch......that's the way I am thinking.....then its 100% heat 0% light....

Whereas LEDs give just reduced light with reduced voltage....but the colour of the light remains approximately the same, whereas the filament changes colour.....

You wrote, "then its 100% heat 0% light...."

Actually, you still have light, but at a lower wavelength than the eye can detect - infrared. So the emission frequency shifts downward, no?

.....and you have infra red eyes?

Hallo Superman!!!!

Your comment did not bring us even 1 mm further on!!!

I have an old English three-speed bicycle with a generator hub. The orginal bulbs didn't put out enough light unless you were going real fast. I found some screw-base LED flashlight bulbs at Super Bright LEDs and they start flickering at a fast walk and become a steady glow as I pick up speed. But cars still liked to pull out if front of me at night so I got the brightest LED headlamp I could buy and now I look them right in the eyes it may be rude but at least I get their attention.

While I was at it I ordered LEDs for my flashlights to upgrade them rather than buying new ones. A couple of them were flashlight/floodlight combinations with a flourescent bulb so now I have the best of both worlds.

I was at an EMC conference last week and saw a demonstration by one of the exhibiting companies, a test house specialising in EMC.

They had been asked to test a floot lamp designed for use with LED bulbs...and it failed. They tried with several other LED bulbs and only one passed. Their demonstration was to turn the lamp on and off whilst a DAB radio didnot/did play.

They tried stripping down the bulb and retesting and found that it was the power supply (transformer I think) that was causing the problem.

EMC Fundamentals

I want to help, I've been heccled on my invention in (sustainable engineering) because I can't spell ! Bla Bla, LED are in most cases more efficient that's fact, they use considerably less power but provide the same amount light... But a 20W LED will youse exactly the same amount of power that a 20W oldy fashioned type bulb will youse, I'm no expert, and I hope this helps you. And for any of you SMART ALEX, I'd you to note my explanation was presented with NO SARCASM, we should help our less knowledgeable brothers and sisters without RUDENESS, if you can't help without a tease then don't

Absolutely correct, though many won't understand why!!!

Usually (so that more understand it) the wattage is also given in a manner that allows a comparison to a conventional lamp's light output.....easier for the masses to understand.

Something like an 11 watt LED gives a similar amount of light as a 75 watt incandescent for example....(this is only an example, it may not be entirely exact for any particular make of LED lighting).

Still not sure how all this works.... Was the comment you made.. When u said "absolutely right" in support of wot I'd said about sarcasm?................. have an iPhone , it's rubbish, non logical, I can only see a small part of anything I look at and zooming around I kinda lose the thread, also the sentences I make all just get bunched into one BLOCK of txt, so I hope my punctuating makes it clear, And who puts in all those lovely little sayings, ie "why do we fall, So we can get back up again" etc etc, r they computer generated or wOt

What you said was true.....I was not being sarcastic.......or did you write what you wanted to say wrongly.......

With regard to Apple products, anyone who buys ANYTHING from Apple has only themselves to blame.....

Fantastic dude, and thanks for your support, I'd give u a little yellow smiley face but I'm not that cleva yet, wot should I have bought, I make all my own power yousing 3x55watt p/v's ok solar panels!, so I really do only have wot I collect, .... So power is my main concern, Death to apple and it's useless products, a real shame cuse they could have been the best, I'm sooo glad I can have a bash at these people in public,....in Fact MY APPLE IS A LEMON' oh that feels good

youse obviously are on the wrong forum

look up on the editor bar & you will find the speel chunker [ABC w/ a check mark underneath]

I once kept a LED circuit flashing for 6 months with an AAA battery. I find it hard to say that an LED is in efficent.

Ron