Re: [Elecraft] totally OT, except to the extent that it's QRP: LED lamps
On Apr 3, 2009, at 5:22 PM, Don Wilhelm wrote: Wayne, that may be fine for your warm California weather, but for other places the wattage benefit is not as great. Consider that, during cold weather, the heating plant must now make up for those 234 watts no longer being dissipated by the bulbs. :-) You laugh -- But! My father was a Chemistry professor at a small college in West Virginia. In the late 60's they designed and built a new Science building, which opened in 1971. In the mid-70s, during the energy crisis, the college decided to try and save money by turning off all lights in the building at night. This was OK until winter came. They found that the heating system in the new building was running 100% of the time overnight, but the building temperature was still in the low 60s in the mornings. It turns out that the architects of the building had factored the heat output of all the florescent lighting in the building hallways. In fact, the lights were positioned just below the air returns for the HVAC system for this purpose. It was actually a brilliant bit of engineering. So, they ended up leaving all the lights on in the winter. Bill Coleman, AA4LR, PP-ASELMail: aa...@arrl.net Web: http://boringhamradiopart.blogspot.com Quote: Not within a thousand years will man ever fly! -- Wilbur Wright, 1901 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] totally OT, except to the extent that it's QRP: LED lamps
Perhaps the time is now right to replace domestic lighting circuits with 12V supply, then the cost of the fitments will come down, ie no need for 110/240V conversion to low dc for the leds. Safer, cheaper, more reliable, less raw materials. At those power levels, you could probably keep the original house wiring and just fit a 12V transformer/rectifier. Easier to use alternative power sources, too. Be nice if we had your prices over here. David G3UNA - Original Message - From: wayne burdick n...@elecraft.com To: Elecraft Reflector elecraft@mailman.qth.net Sent: Friday, April 03, 2009 9:59 PM Subject: [Elecraft] totally OT, except to the extent that it's QRP: LED lamps I just replaced four gas-guzzling incandescent lamps in my dining room chandelier with four LED lamps that screw into the same bases. Went from 240 watts to 6 watts, total. The usual complaint about LED lamps is the cost. But prices are coming down fast: these were only about $4 each at Costco. Each contains 21 white LEDs, and they basically last forever, which means I won't constantly be replacing lamps in this fixture. If the world converts to LED lighting, we won't need to build any more power plants, and we can all use KW amps guilt-free :) Wayne N6KR __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] totally OT, except to the extent that it's QRP: LED lamps
I think that's 50, MTBF. I've got one here that stopped working after a week - I guess there is a 100,000 hour unit waiting to be picked up out there :-) Hmm. It does say 'RoHS' on the base... Pete F5VNB wayne burdick wrote: Hi Allen, The new LED bulbs are rated for 5 hours, but this is a guess, because they haven't burned out yet even in accellerated life tests :) __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
[Elecraft] totally OT, except to the extent that it's QRP: LED lamps
I just replaced four gas-guzzling incandescent lamps in my dining room chandelier with four LED lamps that screw into the same bases. Went from 240 watts to 6 watts, total. The usual complaint about LED lamps is the cost. But prices are coming down fast: these were only about $4 each at Costco. Each contains 21 white LEDs, and they basically last forever, which means I won't constantly be replacing lamps in this fixture. If the world converts to LED lighting, we won't need to build any more power plants, and we can all use KW amps guilt-free :) Wayne N6KR __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] totally OT, except to the extent that it's QRP: LED lamps
How are the power supplies in these little beasties? Are they noisy? Could they be? Buck k4ia k3#101 In a message dated 4/3/2009 4:58:06 P.M. Eastern Daylight Time, n...@elecraft.com writes: I just replaced four gas-guzzling incandescent lamps in my dining room chandelier with four LED lamps that screw into the same bases. Went from 240 watts to 6 watts, total. The usual complaint about LED lamps is the cost. But prices are coming down fast: these were only about $4 each at Costco. Each contains 21 white LEDs, and they basically last forever, which means I won't constantly be replacing lamps in this fixture. If the world converts to LED lighting, we won't need to build any more power plants, and we can all use KW amps guilt-free :) Wayne N6KR __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html **Hurry! April 15th is almost here. File your Federal taxes FREE with TaxACT. (http://pr.atwola.com/promoclk/100126575x1220714320x1201367638/aol?redir=http:%2F%2Fwww.taxact.com%2F08tax.asp%3Fsc%3D084102950001%26p%3D82) __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] totally OT, except to the extent that it's QRP: LED lamps
I haven't heard any noise from them yet. Since they run directly from 110 VAC, I imagine it's just a bridge rectifier, a resistor, and a filter cap. I wouldn't expect any RF noise. Wayne On Apr 3, 2009, at 2:03 PM, k...@aol.com wrote: How are the power supplies in these little beasties? Are they noisy? Could they be? Buck k4ia k3#101 --- http://www.elecraft.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] totally OT, except to the extent that it's QRP: LED lamps
Sorry, I just can't resist ... Wayne, that may be fine for your warm California weather, but for other places the wattage benefit is not as great. Consider that, during cold weather, the heating plant must now make up for those 234 watts no longer being dissipated by the bulbs. :-) Actually, we heat our home with geo-thermal energy and have a good solar room, so for those with similar efficient heating systems, those lower wattage lamps may create a good savings for both my electric bill and the planet. 73, Don W3FPR wayne burdick wrote: I just replaced four gas-guzzling incandescent lamps in my dining room chandelier with four LED lamps that screw into the same bases. Went from 240 watts to 6 watts, total. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] totally OT, except to the extent that it's QRP: LED lamps
I don't know about the rest of you but I turn on an incandescent light when I go into my radio room. It gets the chill out of the air. Currently it is snowing and it has been snowing intermittently for the last week. Winter still holds a tight grasp on this mountain. Since I heat with wood not all rooms are the same temperature. The radio room is normally closed so it can be 40 degrees in there when I open the door. That incandescent light has made life much more comfortable at the paddles. Since solid state gear does not throw off as much heat as tube gear I cannot warm my fingers between stints of sending by holding them over the rig. I am very glad I use that light. It is only 60 watts but I can direct it at my hands and it does offer the side benefit of providing extra light ;) 73, Kevin. KD5ONS -Original Message- From: Don Wilhelm w3...@embarqmail.com Sent: Apr 3, 2009 5:22 PM To: wayne burdick n...@elecraft.com Cc: Elecraft Reflector elecraft@mailman.qth.net Subject: Re: [Elecraft] totally OT, except to the extent that it's QRP: LED lamps Sorry, I just can't resist ... Wayne, that may be fine for your warm California weather, but for other places the wattage benefit is not as great. Consider that, during cold weather, the heating plant must now make up for those 234 watts no longer being dissipated by the bulbs. :-) Actually, we heat our home with geo-thermal energy and have a good solar room, so for those with similar efficient heating systems, those lower wattage lamps may create a good savings for both my electric bill and the planet. 73, Don W3FPR wayne burdick wrote: I just replaced four gas-guzzling incandescent lamps in my dining room chandelier with four LED lamps that screw into the same bases. Went from 240 watts to 6 watts, total. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] totally OT, except to the extent that it's QRP: LED lamps
I hope you have good luck with longevity. We replaced hundreds of exit light bulbs with LED types at my previous job. They did not last long enough to pay for any energy savings. Granted, that was 10 years ago, maybe technology has improved to a point that they are a viable option. I will be interested to see what your opinion is in a year or two. At my home I have changed over to compact fluorescent bulbs, decent light, good life, the only bad I have found is that they take a few moments to come up to full brightness (temperature really affects this). wayne burdick wrote: white LEDs, and they basically last forever, which means I won't constantly be replacing lamps in this fixture. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] totally OT, except to the extent that it's QRP: LED lamps
On Fri, 2009-04-03 at 13:59 -0700, wayne burdick wrote: I just replaced four gas-guzzling incandescent lamps in my dining room chandelier with four LED lamps that screw into the same bases. Went from 240 watts to 6 watts, total. The usual complaint about LED lamps is the cost. But prices are coming down fast: these were only about $4 each at Costco. Each contains 21 white LEDs, and they basically last forever, which means I won't constantly be replacing lamps in this fixture. If the world converts to LED lighting, we won't need to build any more power plants, and we can all use KW amps guilt-free :) Wayne N6KR Do they really last forever? I have had bad luck with LED night lights gradually getting dimmer over a period of a few months. Do the incandescent replacements have any specs on that? Al N1AL __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] totally OT, except to the extent that it's QRP: LED lamps
Hi Allen, The new LED bulbs are rated for 5 hours, but this is a guess, because they haven't burned out yet even in accellerated life tests :) Your older LED lamps probably failed because they were using a very small number of LEDs, driven to very high current. Newer LED bulbs use dozens of LEDs, each running at low current. 73, Wayne On Apr 3, 2009, at 2:40 PM, Allen Wisbey wrote: I hope you have good luck with longevity. We replaced hundreds of exit light bulbs with LED types at my previous job. They did not last long enough to pay for any energy savings. Granted, that was 10 years ago, maybe technology has improved to a point that they are a viable option --- http://www.elecraft.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] totally OT, except to the extent that it's QRP: LED lamps
There's a Department of Energy report at http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/lifetime_white_leds_aug16_r1.pdf on white LED lifetime. Their conclusion is that if the LED is properly heat sunk, (heat sinked?) the lifetime should be around 35,000 - 50,000 hours. I suspect that there's a you get what you pay for in this regard, in that cheap LED lamps are not going to approach these figures but properly designed and manufactured ones will. I've disassembled a couple of cheap CFLs and I strongly suspect they won't last very long. The ones I disassembled failed for several reasons, including a drop onto the floor, but running them with base up is deadly - apparently the CFLs are designed with the assumption that they will be run base down for proper cooling. Some CFLs are expressly rated for base up operation and should be used when that's the operating mode. Jack K8ZOA Alan Bloom wrote: On Fri, 2009-04-03 at 13:59 -0700, wayne burdick wrote: I just replaced four gas-guzzling incandescent lamps in my dining room chandelier with four LED lamps that screw into the same bases. Went from 240 watts to 6 watts, total. The usual complaint about LED lamps is the cost. But prices are coming down fast: these were only about $4 each at Costco. Each contains 21 white LEDs, and they basically last forever, which means I won't constantly be replacing lamps in this fixture. If the world converts to LED lighting, we won't need to build any more power plants, and we can all use KW amps guilt-free :) Wayne N6KR Do they really last forever? I have had bad luck with LED night lights gradually getting dimmer over a period of a few months. Do the incandescent replacements have any specs on that? Al N1AL __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] totally OT, except to the extent that it's QRP: LED lamps
Many years ago I managed the optoelectronics portion of a large U.S. semiconductor operation. We weren't very good at what we did and I suffered through several quality issues as a result, so I feel I have some backside expertise in this area. The lifetime of an LED is a function of four things ... the size and density of crystal lattice defects in the chip itself, the current density through the junction, the temperature of the chip, and the reliability of the connections to it. While current density typically determines the temperature of the chip, high current density alone will propagate crystal defects even if the temperature is held very low in a cold liquid. There are various methods for creating the semiconductor junction of an LED and some are more efficient than others in terms of light per watt, but lattice defects negatively affect power out efficiency in all cases, and it is the propagation of those defects that causes the devices to dim over time. In recent years, process design and control has improved to the point where light output efficiency has reached levels I never dreamed were possible, which almost for sure means that lattice defect densities (and therefore device lifetimes) are much improved. And as Wayne says, that higher efficiency allows the devices to be run cooler ... which also would make them live even longer. It seems to me that the life of modern LEDS should mostly be determined by how hard they are being driven (several LEDs driven moderately versus a few being abused), the effectiveness of the heat sinking for the LED package and whatever it is fastened to (I suspect most designs rely on the leads to carry away the heat), and the interconnections to the chip. With reasonable design margins and not too much carelessness on the packagings side, I'd expect them to last a very long time. By the way, I don't think a bridge rectifier is really needed. If I were doing the design, I'd probably just use two strings of LEDs back-to-back across the AC line ... driven slight harder but with an inherent 50% duty cycle. The distributed heat dissipation of several LEDs might be easier to deal with than the dissipation in the single bridge rectifier. It would probably be prudent to include some sort of current limiting to protect against line surges, but since LED forward I-V curves are not very sharp even that might not be needed in some cases. I would bet that there is more variation in individual LED brightness than there is in the forward voltage curves. In my opinion, there are very good reasons why automobile tail lights and traffic signals almost universally use LED lamps now. 73, Dave AB7E wayne burdick wrote: Hi Allen, The new LED bulbs are rated for 5 hours, but this is a guess, because they haven't burned out yet even in accellerated life tests :) Your older LED lamps probably failed because they were using a very small number of LEDs, driven to very high current. Newer LED bulbs use dozens of LEDs, each running at low current. 73, Wayne On Apr 3, 2009, at 2:40 PM, Allen Wisbey wrote: I hope you have good luck with longevity. We replaced hundreds of exit light bulbs with LED types at my previous job. They did not last long enough to pay for any energy savings. Granted, that was 10 years ago, maybe technology has improved to a point that they are a viable option --- http://www.elecraft.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
