Remember watts are watts.
When you hear about a “14W” LED lamp, that means that the LED itself is dissipating 14W. With well-engineered heatsinking LED lamps should be able to last their rated lifetimes - 20-50,000 hours. I just built a dusk-to-dawn LED floodlight using two 4W Acriche LEDs. The LEDs are heatsunk to the case, and the LED package temperature only rises about 10°C over ambient.
what is “hot” to you or me is not necessarily “hot” to a semiconductor or a piece of metal.
well that is certainly a realistic statement and if I remember correctly beowulff designs LED lights so all your input is absorbed. But my meaning of hot is well above ambient temperature +10C. The lights I’ve seen on display are hot to the touch. About as hot as my 60 watt equivalent CFL’s. The heat sinks looked like they were ceramic.
The other problem with LED technology is that I can buy CFL’s for 26 cents as part of a state mandated incentive program.
Currently, it’s hard to beat CFLs in W/$. LEDs might have a slight edge when energy costs and lifetime is figured in, but I doubt it. CFLs are a pretty mature technology - LEDs for area lighting are really only a handful of years old.
A lot of thought goes into making a LED lamp that is designed to replace an incandescent one. Here is some discussion (long, technical): http://www.led-professional.com/downloads/LpR_13_468932.pdf
Here is a lamp with active cooling: http://www.earthled.com/evolux-led-light-bulb.html
I think LEDs will really take off when they are designed into new light fixtures specifically designed for them. Expecting them to replace standard “A19” lamps is really asking a lot.
FWIW, I did a video of the teardown of my cheapo Chinese LED lamps - here: http://www.youtube.com/watch?v=BKUEgnLpeQo
wow, those things are crap.
by the way, this is a teardown of the Philips LED bulbs I use:
http://www.edn.com/blog/PowerSource/40512-Remote_Phosphors_Philips_LED_bulb_Tear_down_Part_II.php
I’m not sure if they’re yet available in 230 VAC regions.
Aren’t they?
I’ve also only just learned that the CE symbol on these devices isn’t anything to do with the European standards mark ( here: CE marking - Wikipedia ), but is in fact a 'China Exports symbol designed to resemble it.
(I mean, I didn’t expect the genuine CE mark to be meaningful if found here - anyone can apply a sticker - but this is a marking designed to be mistaken as something else - an institutional problem)
How good are the Philips lamps? Can you use them in an enclosed fixture? Do they throw light in all directions? Are they indistinguishable from an incandescent in an adjacent socket? I’m tempted to buy one now to play with.
I still maintain that if we’re in fact going to ban incandescent lamps it would be better to ban the socket rather than the bulb. The phaseout would take a a lot longer but in the first place we could put high quality ballasts in the fixture instead of cheap junk in the bulb, and ensure the fixtures and bulb are designed for each other as far as heat, size, light throw, and such. That’s the approach being used with mercury vapor lamps; replacement fixtures and ballasts have been banned since 2008. As often as people seem to replace light fixtures it would be only a matter of time till most people have fixtures that use and were designed for energy saving bulbs.
I picked up one of the Philips lamps since Home Depot had them for $15.00. I’m going to play around with it some, but my initial assessment is the light quality is vastly better than any CFL I’ve seen, but they still only dim down to 10% or so and can’t be used in enclosed fixtures which preclude widespread use at my house. The package says “for leading edge dimmers”. I don’t know what type of dimmers my Insteon dimmers are, but whatever it is they do work fine apart from the around 10% cufoff. One good place for them might be the coach lights since LEDs aren’t bothered by cold, the lights burn from dusk till 10:00 every day, and although the coach lights are on a dimmer like every other Edison socket in the house I actually don’t care how much or even if they dim at all.
I decided it was time for another try, despite my negative experience and naive hopes regarding the cheapie Chinese bulbs.
The 4ft fluorescent tube fitting in my kitchen failed last week, so I replaced it with this - it’s got a Phillips switched mode PSU in the central unit and each of the swivel heads has three LEDs in it.
I am quite impressed with this - it’s nice and bright - the coverage of light is obviously more uneven than it was with the old fluorescent tube, but that’s not actually a bad thing - in this case, it adds mood. I’m very pleased with the colour and spectrum of the light - it’s quite a warm colour, but it seems to give a very natural even lighting effect - and objects of any colour look properly illuminated (to the extent that it even works for simple digital photography - the camera’s white balance kicked in, but the result still looked natural - which is not often the case for artificial lighting)
It wasn’t cheap, and the individual LEDs don’t seem to be replaceable, but it’s guaranteed for 20 years.
That is about $141 US. Not bad for a such a fixture that you’re not suppose to have to worry about changing bulbs and over 20 years would pay for itself versus incandescent bulbs at very least and maybe the fluorescent tubes also. A standard 4 direction fixture could run the same price and at least half as much. Tube lights tend to not look very nice in living areas and are more industrial, office, shop or garage appropriate.
I have one LED standard fixture bulb in my bedroom that I really like so far that I got at Home Depot for $10. The dimming is not as good as I would like but good enough and so much better then my attempt with a dimmable CFL.
I also had 3 EagleLight brand LEDs that have been terrible. 2 burnt out, it was extremely hard to get a replacement and then they only sent one. The light is dim and the company has no quality control from what I can see. I still have the dead ones, I think I will take one apart.
I plan to buy a few more of the other LEDs from Home Depot. I am really impressed with it overall.
ETA: The bulb I like is a 40w equiv http://www.homedepot.com/Electrical-Light-Bulbs-LED-Light-Bulbs/h_d1/N-5yc1vZbm79Z12kx/R-202188260/h_d2/ProductDisplay?catalogId=10053&langId=-1&storeId=10051
I have virtually the same complaint with the fluorescents here in Thailand. I constantly remark how they are somehow able to make a room look darker and more dismal when you turn them on. The reason is because they create such a bright spot in the ceiling fixture that your view of the room is “overexposed” because you always seem to have a bright spot in your field of view. Making matters worse, many houses here seem to install fluorescent bulbs inside recessed ceiling light fixtures. A recessed fixture needs a unidirectional light source, like a spot light. Omnidirectional fluorescents have no business being stuck up inside a hole in the ceiling.
There is a room in my house that has six of these recessed fixtures in the ceiling, controlled in pairs by three switches (I guess that’s their version of dimming). But even with all six lights on, I often need to grab one of my super-bright LED flashlights if I want to get a good look at anything that doesn’t happen to be positioned directly under one of the six ceiling fixtures.
OK I’m done ranting about fluorecents now. Aside from that, I’ve had the same experience with LED replacements. I’ve tested a handful of them and they always end up in task lighting like desk lamps, under-cabinet lights and reading lamps, where I’m not expecting them to light up a room.
And those small circuit boards remind me of boards from the 70’s and 80’s when engineers were still trying to figure out how to put big things (like 10W metal film resistors) into small places.
I just took apart that Eaglelight bulb and it is amazingly flimsy wiring inside, $ store quality in my opinion. However, sadly that was not the problem. It appears that amid some sloppy looking soldering on the board, the tiny IC chip that probably does the job of the AC-DC rectifier is the culprit. I had my hopes it was just the wiring and I could fix it. I actually got the unit to flash once but not again. The larger components all appear to be fine on testing; a capacitor and 2 transistors. Though to be fair, I did not do a good test on the cap and it could be the problem, it would even possibly explain the brief lighting I saw.
CFL and LED both come in a reflectored bulb package (PAR). i don’t have experience with any.
I could have picked up a similar-looking fixture (or one with six lights) for about one third of that price (or half, once I’d bought the bulbs), but that would have been GU10 halogen spots, which are 50W per bulb. This one is 4 x 7.5W - which I think is about the same as the fluorescent tube it replaces - although fluorescents consume a big gulp of power on startup - and where the LED unit is instant-on, there’s not so much temptation to leave it switched on when leaving the room for a short time.
Sounds like what I found inside the corncob bulbs I bought and ultimately tore down. The little chip thing is probably a packaged bridge rectifier (like this?)
That is it and the likeliest problem. It looked like this one.
If that’s all there is to the conversion from AC then there should be an industry standard replacement system that allows you to replace it like a plug-in fuse. That would go a long way toward making these things functionally useful. I’d be much more likely to spend $100 on a bulb if I could service the whole thing for $10.
I guess - although the fact that it failed is perhaps indicative of it not being the ideal solution.