It has been a long time, but I am back. I hope to keep this blog more up to date.
Today I would like to talk a bit about a thread on TheOilDrum about LED lighting. I put in my two-cents worth, but was shouted down for the most part by people who think they know about LEDs. So what did they say?
DaveMart asked about a press release about Delta's new LED products. AlanfromBigEasy responded with his view of LEDs and how they fit in today's world:
"I use a mixture of LEDs and CFLs at home. It is interesting if a 5 watt LED can put out slightly more light than a 5 watt CFL, but hardly a revolution yet.
Such a 5 watt LED will cost more than $20 (perhaps $50 or $100) vs. a few $ for a good 5 watt CFL. A lot of money for slightly more lumens. ... And for enough lumens to light a room enough to read by, a LED has heat dissipation, as well as cost problems. ... AFAIK, no one has put out an Edison base LED that can put out 700 or more lumens. The reason is heat dissipation (which kills LEDs).
I have a USB powered LED task light for by keyboard and a 7 watt CFL for the area. I have a 0.7 watt red LED bulb besides my bed so I can see enough to turn on a "slow on" CFL (13 watts ?). A "Y" adapter for the bathroom light. A 1.4 watt LED for quick visit, I quarter twist a CFL for bathing, shaving, etc. (CFLs do not like quick on/off cycles, they die quickly). [also have] A 1.4 watt (I think) yellow LED over the door outside.
LEDs have a few useful niches such as where low light levels are all that is required, colored lights, where vibration is an issue (cars) and frequent on/off cycles. BUT CFLs have a larger niche."
Alan confuses the value of LEDs over that of CFLs by measuring value by the relative cost/lumen. He fails to consider lifetime and environmental factors. He also worries about "heat dissipation" problems with LEDs and uses that for the argument that larger LED fixtures are not possible -- but he is wrong. Finally, he argues that LEDs have "a few useful niches" where low light levels are all that is required. He does not realize LEDs can produce as much light as needed with the proper design.
I agree that CFLs have a large niche, but that is because WalMart and Costco have been pushing on the marketing end.
Marco comments on Seoul's new 4die LED at 900 Lumens (@ 90 lm/w) and Paul at HereinHalifax comments about issues regarding typical light flux, color temperature, life expectancy, and lumen maintenance. He adds the comment
"Lastly, there's the issue of fixture optics. LEDs can be a great choice where a moderate amount of light is concentrated in a narrow beam (e.g., a torch light), but they're not well suited for general illumination, as in the case of a table or floor lamp. Given the nature of their light distribution, I don't see how LEDs will ever replace general service lamps."
Once again we have a case where people are talking about LEDs when they have not seen the full range of product. LightBlasters' HyBright LEDs have a 150 degree cone of lighting and are not focused into a narrow beam like the last generation of LEDs have required. LEDs do replace general service lamps! I responded
"Paul, your last comment is incorrect. LEDs WILL replace general service lamps. We are doing this already in RVs. What is required is to use the latest generation of HyBright LEDs used in LightBlasters' nexLED products that spread their 20 lumens of light over a cone of 150 degrees out from the surface of the chip. Earlier generations of LEDs are limited to as few as 15 degrees at only 3 lumens."
I then went on to say
"I offer my experience.
I live entirely in an LED environment, having replaced all my incandescents bulbs and fluorescent fixtures with LED equivalents. The amount of light I have is the same as what I had before. The power consumption is about 15% of what I used before, low enough that I easily run on batteries charged by solar power during the day for my lighting at night.
The keys to doing this are 1) having a 12-volt DC electrical system available, 2) having a different attitude toward lighting, and 3) not trying to illuminate a 4,000 sqft McMansion with light I will never use.
My first secret is that I live in an RV (fifth-wheel trailer in my case). It has a basic 12-volt wiring system throughout, and all my LED lights run on that 12-volts DC system. So the conversion to LEDs was rather simple. In a "stick-home" with 120VAC system, it is necessary to convert the AC into the DC that the LEDs require (though some LED products can operate attached to an AC line by clipping out only that part of the current when the polarity is right. The problem is they flicker at 60 cycles per second.)
There are a number of low-voltage converters (120VAC to 12VDC) available on the market. Many of the lawn lighting systems use such converters. It is possible place such a converter into a strategic cupboard and to extend the wiring from that unit throughout a house to make the power available where you need it. The good thing about LEDs is that they typically require only milliamps of current, not amps, so smaller wire can be used. For isolated local applications, I also use a very small converter plugged into a wall socket.
The second secret is attitude. I want my light where I need it. Low-level ambient light around the room is okay, but I use light to see to read, or to build small electronic toys. My wife uses light to sew and to cook and do the dishes. We use a light over the dining table to eat. There is no need to have a bright 300watt bulb lighting the far corner of the living room. The intensity of the light from a bulb falls off as the inverse of the distance squared, so the closer the source is to where you need it, the better. Put your lighting fixtures close to where you need them. I also like to use linear light rather than point light. We have lightstrips around the mirror of our vanity rather than six large, bright incandescent bulbs with their six points of light. They spread the light out and make the area much more useful.
The third secret is space. It helps that I live in 320 square feet of living space. Of course, it also helps that I have the Cleveland National Forest (or wherever we happened to be camped) just out my front door as my yard. Don't live in more space than you need. Don't try to light space that you do not need.
Now one of the questions was the brightness of the LEDs compared to CFLs or incandescents. Products are available that produce as many lumens of good "white" light as a CFL where you need them using only one-third the power. You also don't have to be concerned with the bit of UV from a fluorescent or the bit of mercury in the CFL when it dies. And the LED will last 20 times longer than a CFL. When you compare the LED to incandescents, you use 15% of the power for 100 times the lifetime.
Another question was cost. Yes, good LEDs are expensive (unfortunately, most of the really cheap ones are dim and failure prone). but the payback comes from long life and much less power consumption. At this point, good 12-volt DC LED lights retail for about $10 for 50 lumens (using about 0.7 watts of power), and you can add more LEDs to build lamps with 300 or more lumens (4.2 watts for $60).
And by the way, incandescent lights create 7 times the heat as LEDs for the same amount of light. Unless you are heating your home by turning on the lights, you may need to run the air conditioner to remove that extra heat. Use the rule of thumb that it takes twice the energy to remove the heat as to generate it.
I believe the future of lighting is in the LEDs (unless it turns out to be a wood fire). It should be what you go for now.
Sam Penny
the Prudent RVer"
There is more in the thread, but it gets off on the color rendering index and other specifics.
It was a good discussion about LEDs, and there need to be more on similar forums. Keep your eyes open for such discussions; people are beginning to be more aware of the place of LEDs in our future.
Sam Penny
the Prudent RVer
