LED not that efficient.
 

After reading around on the Internet I was finding that LEDs are supposedly good gor around 100 lumend per watt. I thought that's pretty good. So I went around checked one of each kind of LED I have, most of which were bought last year. They are only doing 65 to 80 lumen per watt, or 60 to 76 per volt-amp.
Volt-amp is a better measure of somethings power supply inefficiency, plus I have found the power company charges for watts but penalizes for low power factor when your volt amps are higher than watts.
For example CFL with their tiny cheap ballast will use 23 watts and 40 volt-amps on a 100w replacement, so they are really only about double the efficiency of a regular 100w light bulb which also uses 100va.
A 100w replacement LED will use less than 20va so it's a little more than 5x efficient than an incandescent, and at least double the efficiency of a CFL. Which is pretty good.

But I don't know where any of these unicorn 100 lumen per watt LEDs can be purchased.
I got looking into this because I was told that my T5 lights were inefficient, outdated florescents and that I should replace them with LED. Well it turns out that my T5 lights are doing 90 to 105 lumen per volt amp depending on if it's a high output or standard.
Way more efficient than any LED I can currently buy.
All the ones that I can find do well under 100 lumen per watt, then I see some cheap Chinese crap claiming to do something like 160 lumen per watt I'm suspicious that they just wrote numbers on the box to move product.
I have found lots of complaints about no name Chinese LEDs being comically over rated.
So for now I'm going to keep using my T5 fixtures.
I'm glad I didn't just assume LED were more efficient and go waste money replacing my T5 lights with them.

Yes, but a factor you're missing in your T5 fixture calculations is that florescents radiate light omnidirectionally. This means a shocking amount of their light just bounces around the fixture and never leaves it. To the tune of 30-40%.

Likewise, the rated lumens on a fluorescent tube are for its initial light output (light output after 100 hours of "seasoning"). The actual mean light output will be approximately 10% lower.

Finally, and this is a biggie, buy dimmable LED tubes. You'll be surprised just how little time you need the full blast output... most of mine have the dinner set to around 50% and that'll go to 80-100% maybe once a week.

EDIT: LEDs also don't leak nearly as much UV as fluorescents. My work still uses T8 tubes, and anything you print in ink will be faded garbage after only a year or two :-/

I could get dimmable T5 ballasts for my dead fixtures, but I don't want them.
I don't know how the light would bounce around in the fixture half of its open.
Cheap Chinese tubes fade after a little use, I use mostly 30,000hr German tubes.
T8 tubes suck.

Another concern is the upper operating environment temperature limit on my LED tube is only 113°F.
My shed is easily go to hit that this summer. My garage, hopefully not.

T5 run in a 120°F environment no problem.

Maybe it is the type of bulb? Are you trying to find LED tube bulbs to retrofit old fluorescent fixtures?

My Cree A21 (traditional incandescents looking) bulbs are 1700 lumens / 15 watts = 113 lumens per watt

EDIT: It might be color too. The "Soft White 2700K" version of my bulbs are only 100 lumens per watt.

I found this out a while ago. LEDs are not rated the same as Incan or flour because they don't "burn out" but instead just get dimmer and dimmer. Caveat emptor. I bought LEDs from a big box store and their output dropped 20% in a month.

But how many volt-amps are the 100+ lumen per watt lights using?
Cheap power supply inefficiency is a big part of the problem.

I bought some Sylvania "250 watt replacements" about 4 years ago back when they were pushing $44 each after sales tax.
Then I moved, took the old LEDs with me and installed them at my new place, then went back and bought more of the exact same led floods when I installed more lights, now $33 each.
As far as I can tell the new and old ones don't look any different from each other.
But the old ones were also on a timer, so they were rarely ever on more than 30min. So they may still be like new.

The Cree 15 watt bulbs are in the ceiling so we will have to be content with the smaller bulbs from the lamps.

CREE: 860 lumens / 9 watts / 120V / 75 mA / 5000K (95.5 lumen / VA)
FEIT: 1600 lumens / 15 watts / 120V / 140 mA / 5000K (95.2 lumen / VA)

Where do I get these and how much are they?

The power company sells by the watt, not by the volt-amp...So, unless they're lying as to the actual power consumption of each bulb, the stated wattage is what you will be paying.

As far as I understand it, the power difference between V-A and watts isn't lost, so presumably the power company gets it back (minus losses), and just sells it to someone else. If it doesn't get dumped in to some other part of your circuit, like some purely resistive load that doesn't care.

Now, for someone who isn't connected to the grid, I'd assume power-factor has a HUGE impact on efficiency. Which is probably why you've taken note of it.

I would assume, like most things, that the PF (Volt-amps vs actual watts, for those reading) for LEDs is mostly determined by the tiny built in power supply that converts the AC in to whatever voltage DC needed to "Drive" the LEDs. Correct me if I'm wrong, but I would assume the inefficiencies you're pointing out come from said power supply, not from the LEDs themselves. Simple power supplies (like a transformer) tend not to be very efficient. I would assume for the sake of cost-savings, that LED bulbs use cheap - not very efficient - power supplies.

If they were powered from DC from the start, you wouldn't have any of this power-factor issue. That being said, there are ways to convert A/C to DC efficiently, with a power factor of 1 (to 1)...I would think if you used one of these to power/drive all your LEDs off one such source, it would be quite efficient over-all. You could power each bulb individually, but it would probably be cost prohibitive.

The chargers for my EV use switching power supplies and have a PF of 1, or darn close. This helps maximize how much power coming out of the outlet actually gets in to my batteries. It means I can use a 15-amp circuit instead of a 20 (or more) that would be needed for a cruder charger. Also means I don't have to use oversized wires to carry the extra amps moving back and forth.

For those reading who want to understand it...If you tried running 1500w worth of these bulbs off a 15 amp, 120v household circuit...you'd blow your breaker and overload your wiring. You wouldn't be pulling the ~12a that you would with a PF of 1 (like a purely resitive load, like an incandescent bulb or an electric heater)...you could easily be pulling twice that amperage. Half of the power would go right back up the line back to the power company...but they would only charge you for the power(watts) used.

Anyway, to most people, they will never know the difference, particularly with something like a light bulb. To the occasional person who is running thing off an inverter or generator, it can really matter.

Seems the OP knows most of this.

Regarding 100 lumens per watt...you might find the LEDs themselves are actually this efficient. The 110v LED bulbs I use are rated at 7-800 lumens and supposedly consume 8 watts. It's pretty close. And, as you point out, it's the power supply that is killing the V-A. Perhaps it would be as simple as applying ~110v DC to them and you would be free of the V-A inefficiencies. And perhaps the power supplies simply wouldn't work on DC, and the only way you'd be able to do it would be to bypass their power supply and drive them directly. (sounds like a lot of work). You'd need a good, efficient switching power supply if you're starting with AC.

(You used to be able to buy CREE bulbs...as far as I'm concerned, they were the original LEDs that allowed actual bulbs to be manufactured. Other brands have since come out with similar output LEDs, so they're no logner the only option)

How does the utility penalize for low power factor? I thought the meter measures watts, and that's what you pay for?

Concerning T5, I probably wouldn't install them in my garage these days. I wasn't happy with how quickly one of my bulbs went out, and they don't perform so well in cold temperatures, and they take a while to reach full brightness. I'd probably go LED now.

AFAIK, it's only relevant to commercial/industrial usage.

The digital meter I had at my last house had two additional readings that read "KWH 80% P.F." and KWH 60% P.F.", in the world of electrical generation and distribution there aren't very many things that could mean.
Then I have tested an old electro mechanical utility meter powering a 140w 500va 120v welder at no load versus light bulbs.
I found that a 200w light bulb didn't spin the meter nearly as fast as the welder. But the welder spun the meter as fast as a 500w halogen work light.
If the meter only counted watts then the 200w bulb should have spun the meter faster than the 140w 500va welder.
The only logical conclusion is that electromechanical and digital meters do read volt-amps.

As far as I can tell I am the only person to have ever actually tested this.

T5 high output is much better in the cold. I have fired mine up at about 12°F and they came right on, came up to full brightness in about 3 minutes.
But I'm also using enclosed commercial grade HO ballasts and German tubes in most of my fixtures.

My new place came with a pair of standard T5 fixtures with cheap Chinese ballasts and tubes, yeah i agree those are junk. So I know what you are talking about.
I may end up gutting them and putting in 120v T5 LED tubes in them.

It may be that the RATED OUTPUT of your welder was 140w. It may be that it pissed away another X00 watts as waste heat in the transformer/circuitry, and had little to do with power factor. It may also be that just because 140w is it's RATED usage, it can and could put out a lot more for a brief period. Like a typical motor can put out 2 or 3x it's rated output for a limited period.

Or you could be spot on with your deduction. Rather hard to tell without further testing.

140w 500va was what the kill-a-watt meter was showing.
Not ratings on the machine it's self.
That waste heat is physical manifestation of low power factor and excess volt amps.
Going by what the machine name plate says is a rookie mistake. The only things I have found that consistently near name plate is lights and heating elements.
Next?

Random info:

The max that an led can generate is ~680 lumens / W. For green light. In this case you would have 0 heat being generated.

https://www.amazon.com/100-watt-Dimm...electric+bulbs

Sadly, in the name of cheapness, all these multi-pack bulbs forgo the beefy heatsinks of their forbears and have half the rated lifetime.

Something like my flood lights that are outside, only get used when it's cooler out at night and are on a timer the big heat sinks could be foregone.
But inside lights where they could be left on for 24hrs, kind of need the big heat sink.

The CREE bulbs were purchased 4 years ago at Home Depot for about $8 each. That was when 5000K (Daylight) bulbs were hard to find so I splurged and purchased them for the living room. (The rest of the house got 3000K FEIT bulbs for about $2 each)

The FEIT bulbs were purchased at Costco this year for $2 each (after about a 66% credit from Energy Trust Oregon) They are about $7.50 at Home Depot. I replaced all my 3000K bulbs with 5000K and gave the old bulbs to a friend that was still using incandescents.

The older CREE have a beefy heat sink / the FEIT do not.

https://images.homedepot-static.com/...100-64_145.jpg https://images.homedepot-static.com/...-10-64_145.jpg

a lot of white light LED are actually ultra violet LED shining through a micro dot florescent medium.
The medium will burn away over time leaving more and more UV and less white light. the amount of light being generated stays the same.
You just can't see it.
I believe this is caused by the relatively high intensity of UV

Wait, you said you replaced the 3000k FEIT bulbs with the 5000k Cree. The FEIT are the newer bulbs and the Cree older. But then you said you gave the old bulbs (Cree) to a friend, which would leave you with the newer 3000k FEIT.

Anyhow, the main thing missing is which are more energy efficient.

Is this still the most popular way to produce white light from an LED? The other method, and I believe is more efficient, is to combine RGB LEDs into a single package that gives the illusion of white light.

I replaced 4 year old 3000k FEIT bulbs with new 5000k FEIT bulbs

I still have the 5000k CREE bulbs

I don’t care one bit about any marginal difference in efficiency between the 3000k and 5000k bulbs. I was just happy to get rid of the dingy yellow light from the 3000k bulbs. In both cases the LEDs replaced incandescent.

I'm just going to have to go to the store and open boxes to check efficiency to make sure of what I am getting.

I've opened a "burnt out" Feit (or otherwise identical) recently. It was just a bunch of 5630 LEDs fanned out in a circle on a flat piece of aluminum.

Unless the florescent medium is built in to the relatively tiny LED itself, they don't use anything like that.

Maybe the CREE ones do...they tend to have a large hump on top, rather than the totally flat 5630s. (I assued this had to do with spreading the light out)

The phosphorescent white LED were the most common. Don't know if they are falling out of favor.
I think the move away from phosphorescent light emission is the only way LED is going to get a big efficiency jump over tubes.

I pulled the bulb off of one of mine (Luminus brand from Costco, not Fiet).

http://ecomodder.com/forum/attachmen...1&d=1517398104

Still works:

http://ecomodder.com/forum/attachmen...1&d=1517398113

Meaning there's no phosphorescent lining to the inside of the bulb, as I was starting to wonder. I can't see there being enough phosphor on top of those tiny chips, either (but correct me if I'm wrong).

Longevity seems ok, in spite of not having a huge heat sink. I've had to replace 1 that I know of in the past ~2 years, on lights that stay on 24/7. Not completely conclusive, but at least comparable to CFLs, which always seem to croak after a couple of years.

I'll re-purpose this bulb. 800 lumens at 9.5 watts (though double that volt-amp wise) for a couple of bucks? Drool!

Edit: They may very well have a phosphor lining built in to each LED...when you cut the power, the LEDs fade to nothing over a half a second or so. (or does the power supply have a capacitor that takes a moment to discharge?) Might explain the yellow you see on modern LEDs? (they used to all be clear just a few years back). Then again, I have red and yellow LED bulbs that are yellow on top.

Welp, I'm now thoroughly confused. Someone enlighten me!

Edit: it inst a persistent glow, like a CFL...I'm going with capacitor discharge.

Ok ladies and gentlemen, let me clear up some questions surrounding this new LED light fad.

I didn't know this thread existed until I got a message from somewhere else. I don't know if this thread or the other one on ecorenovator got started first, but they are both headed the same direction. Let me tell you this: there is nothing much different than the path LED lighting is on than the path that fluorescent lighting has already traveled.

Ok, so the thing about Cree is that they have expanded their offering by gobbling up their competition. The market has opened up for them in the downward spiral towards Walmart. They still make firefighter headlamp LED stars and off road vehicle light bars and stadium spotlight modules, but now they make a boatload of thirty eleven brands of COB lights. They pioneered the market and have the rights, so now that it has exploded they are getting their cut. Most of the big knock off brands have been assimilated at the source in China.

As you should know, there is no such thing as "pure white" light. White light is a mixture of a broad spectrum of many wavelengths of light. LED lights are made to produce a narrow output at high efficiency. The only way to produce "white" light from them is to either mix emitters or use scintillating phosphors.

The major innovation in LED lighting came in the mid 90's with the refinement of inexpensive blue emitters. It is the blue LED emitter, combined with a yellow phosphor, that makes it economical to produce a single source "white" emitter. The blend of phosphors used determines the "color temperature" of the observed light. So with all of the white emitters, we have a blue LED and a varying amount of different scintillating phosphors used to render a wide range of color temperatures.

As far as raw efficiency goes, we usually get what we paid for. Why would a manufacturing company stick research grade emitters in a lamp they can only sell for a dollar or two? It's just not economical to do so. Like I said, the market is wide open for them in the flea market direction. Ching chong works for Cree now...

Why do you believe LED lighting is a fad? What do you thing will replace it?

I wouldn't be able to stand being in a room with 5000K lights for more than a few minutes. I like 3000K-3500K "halogen" color range; everything higher looks cold and blue to me.

The lights I noticed dropping in intensity were big-box PAR30 long neck replacements. They advertised output rivaling my old halogens, and they delivered it -- for about a month. Now they are putting out far less. They still work, naturally, but I almost wish they'd quit. As to usage, they're in a dark kitchen and are on probably 12 hours/day.

I've resigned myself to paying a premium for Soraa bulbs. So far I'm pleased. They've tended to start out brighter than advertised and then settle into a lower, but still sufficiently high, output. Plus I can pick from a range of color temps and CRI levels.

The yellow part on top of the chip is the phosphor.

But as blue LEDs have become cheaper, UV chips were phased out for blue color with phosphor conversion to the other colors. In filament type bulbs, the phosphor coats the whole stand.

Interesting. Thanks.

Wondered what was up when my 12v leds started showing up with yellow tops. My older ones were all crystal clear. I take it that different phosphor can put out different colors, not just white?

Hey, whatever works. Gonna have to find an old bulb and compare the light output vs a fresh one.

As Jeff points out, the creation of the blue LED was crucial to developing white LEDs. Both methods of producing white light require the blue LED. Combining blue with red and green LEDs creates white light, as well as converting blue to white light using a phosphor.

My assumption is that the phosphor energy conversion involves more loss than combining red/green/blue LEDs to produce white. I would further assume phosphor is the cheaper way to manufacture the light as only 1 PN junction has to be made rather than 3. Don't have time at the moment to research these assumptions, but I'm eager to learn.

I don't see the LED going away anytime soon. What else rivals the efficiency, longevity, and cost? Adjusting intensity using PWM is very efficient.

I am unaware of anything that could replace LED.

Heck my 250w replacement LED floods were originally $44 each they do about 65 lumens per volt-amp.

Sunday I brought out a cheap Harbor Freight dual flood light to work on the car. One of the halogen bulbs went out. What an annoying hassle. I'd pay more up front to not have to replace bulbs and save electricity.

If you have halogen work lights do what I do and get rough service replacements.
I was replacing my 150w motion detector halogen lamp every 2 or 3 months, then I put in a 100w rough service lamp and have not changed the lamp in 3 years.
On a side note I recommend installing a timer on halogen work lights. It will save power and reduce fire hazard.

Longevity is most definitely a part of efficiency. Having something fail, having to toss it and buy a new one of something definitely effects operating cost.
For example, LEDs loose efficiency if they are ran too cold, but the cold doesn't kill them, so they last just about forever.

The only disadvantage I can think of is your led never burns out, so you keep using say 60lumen per volt amp lights even as 150+ lumen LEDs come available, because your old ones just won't die.
But it's going to be a while before high intensity high efficiency compact white LEDs are available.
To get a lot of light from an LED and have it be highly efficient the LED pretty much needs to be its own fixture, that way you can have a huge array of low power LEDs working together to make a lot of light.
The best efficiency is had when you are running less than 10ma across your PN junction.
Run more than that and quantum physics starts cutting into efficiency.

As I understand, the extended life halogens simply output less lumens per watt at the benefit of being more durable. Everything is a trade-off.

I'd just rather not mess with filament light anymore. The work light was my Dad's, so when it comes time for me to get my own, I'll go LED.

Spot lights probably should just be an array of many low power LEDs, each producing either red, green, or blue to produce the desired light output. Perhaps it would cost a bit more, but it would be efficient and long lasting.

RBG is the most efficient way to use LED lights but it more expensive in assembly time

would be a good DIY project you can still get high power LED by the bag
in red blue and green

I made a bunch of 12v LED rings for a friend
it was enjoyable

Back around 2003 I made this LED brake light and turn signals for the motorcycle. Previously I had replaced the license plate bulb with white LEDs, which were fairly new at the time. There were no automotive bulbs, so I crushed the glass bulb and replaced the filiment with 3 LEDs and a current limiting resistor.

Turn signal
http://ecomodder.com/forum/member-re...8-img-7704.jpg

144 LEDs, each one lightly sanded to diffuse the light
http://ecomodder.com/forum/member-re...ummer08272.jpg

Over 300 solder connections
http://ecomodder.com/forum/member-re...ummer08270.jpg

Running light
http://ecomodder.com/forum/member-re...7-img-7701.jpg

Brake light
http://ecomodder.com/forum/member-re...6-img-7695.jpg

License plate LEDs
[IMG]http://ecomodder.com/forum/member-re...52-prom061.jpg[/IMG]

Nice work. Too much work for my tastes, though! I buy LED "dome light" panels in red for my 3rd brake light and such.

http://thumbs3.ebaystatic.com/d/l225...J1zExfv0CQ.jpg

They come in different sizes; if one wont fit properly, I've used two smaller ones side by side instead. Very effective. (I usually go for 5050 LEDs for this purpose)

I only did it because they didn't make LED lights for automotive use back then, and I worked a night shift that had tons of down time. The internet didn't have so much content then, so once I reached the end of it, I needed something to do.

Back in 1998 I paid $8 per white LED and converted my headlamp. I had been going on night hikes every day, and would chew through a set of AA batteries on each hike. Having no money, this was unsustainable.

Rough service bulbs I'm familiar with have heartier filaments with extra support. The idea is that they can take more jostling, not that they put out less light.

I started putting CFL bulbs in my work lights years ago. They don't have to be "rough service" to withstand hard use. But they are starting to die! So are other CFLs in my house.