From: John De Armond Newsgroups: rec.outdoors.rv-travel Subject: Re: LED light results -- short Date: Thu, 30 Mar 2006 00:14:39 -0500 Message-ID: <bopm22p1jshj9u554du015m399b0e70ka1@4ax.com> On Wed, 29 Mar 2006 19:50:04 -0800, "Sorobon" <Sorobon@AOL.com> wrote: >I know this will cause some disagreement. > >I have replaced more than half the lighting in my trailer with LED's. A >little more than a year ago, I read reports on this group, of failures of >the replacement LED clusters -- 24 LED's per bulb in my case. I have used >these lights for 9 months now, over the course of 2 winters. I have had no >failures and have converted some of my friends to their use. The new -- >second generation white LED's have a less blue light and are closer to >normal indoor lighting. One light, I left on all summer while I was on >shore power at home, it still works fine. The LED's are not as "pleasing" >as regular lights. Most of the incondesant fixtures in my trailer had 2 -- >1141 bulbs I replaced 1 bulb with 6 LED's in each fixture. > >If you are boondocking LED's are the way to go, if you staying in RV parks >don't waste your money on LED's. > Actually, LEDs are a poor way to go for boondocking. They're only a little more efficient than incandescents. The way to go for low power is with fluorescents. Especially the compact fluorescents because the rare earth tri-phosphors they use are more efficient than the old halo-phosphates that most conventional fluorescent lamps still use. I have a nifty little 7 watt 12 volt-operated, bayonet-base CF that was sent to me for review (by an importer that went out of business, unfortunately) It outputs many times more light than 7 watts' worth of LEDs. And it's a much more pleasing light, having a spectrum similar to incandescents. Even more efficient than CFLs are the CCFLs (Cold cathode fluorescents.) They achieve better efficiency by virtue of using cold electrodes with no filaments to heat. Here are some examples: 5 whole watts: http://www.blackenergy.com/store/tcpcoldcathodealamp-p-890.html 8 Watts http://www.buylighting.com/ These work just fine when operated from a cheap inverter. If you troll around some of the B2B sites for chinese manufacturers you'll see that these CCFLs are on the next wave of ChiCom invasion. Expect to see CCFLs as cheap as CFLs within a couple of years. John From: John De Armond Newsgroups: rec.outdoors.rv-travel Subject: RV lighting Date: Sun, 30 Apr 2006 22:02:54 -0400 Message-ID: <kuqa52pintulfjh0esjanj3gv4uhevscjm@4ax.com> I got this inquiry in my private mailbox. I thought the answer might be of enough general interest to post a copy of my answer here. ---------------- On Sun, 30 Apr 2006 05:31:02 -0700, someone wrote: >John, > >You have published various bits of very useful info about cold cathode >lighting in the past on RORT. I (and I bet many others who dry camp) am >very interested in low power consumption good quality lighting. I would >love to see a more detailed posting on your web site (with a RORT >pointer when it is there.) You're most welcome. I have a whole bunch of stuff to post to my website once I get some round tuits. I expect to have lots of those while sitting on my butt in my truck passing the DOT quiet hours :-) >I would *like* to see something on ready built stuff or complete >directions for fixtures, ballasts, bulbs and covers (if needed.) Like >many I am reasonably handy and can do my own wiring (and basic handy-man >repairs,) but don't have any cold cathode or significant circuitry >expertise. Designing cold cathode driver electronics to avoid electrode darkening and mercury migration (causes one end of the tube to go dark) is non-trivial so I highly recommend using commercially available stuff. I certainly do. There are basically two types of "cold cathode lighting". One is the traditional neon style, made to order by neon craftsmen. The other type is the high intensity, defined life, small tube diameter stuff as is used in scanners, copiers, computer case lighting and increasingly, general lighting. The difference in the two major types is in the electrode design. Neon electrodes are designed to keep the current density below the level where metallic sputtering occurs. Sputtering occurs when energetic ions impact the electrode with enough energy to knock off atoms of metal or emission coating Sputtering degrades the electrode and buries noble gas atoms under the coating as it plates out as dark areas on the tube. The small tube defined life CCFL uses a much smaller electrode and much higher current density, typically a pin protruding through the glass seal. The diameter pin is nearly that of the tube. The tight fit between the cathode and glass tube somewhat limits ionic velocity that causes sputtering but the end of the pin still sputters so the tube has a defined life, typically 18,00-25,000 hours. That's a lifetime for intermittent use but not all that long for 24/7 operation that many neon sign tubes operate. The small tube CCFL typically runs at a higher current level than conventional neon and that combined with the small tube diameter results in very high surface brightness. The lamp is essentially a line source which makes it handy for things like scanners and copiers. Traditional neon is characterized by larger tube diameters, lower surface intensity (lumens per square inch) very high efficiency and essentially infinite life. Yet another difference is that the small tube CCFL has to warm up to build mercury vapor pressure before it achieves its full light output. it has this characteristic in common with hot cathode CFLs. Traditional neon warms little to none at all so the initial intensity is its normal intensity. OTOH, traditional neon does not do well in cold weather because the mercury vapor pressure drops so rapidly and because the tube generates little heat. A CFL (hot or cold cathode) will generally operate to far below freezing if the tube is surrounded by still air. Traditional neon CCFL pretty much has to be made to order by a neon craftsman. Expect to pay around $30 minimum per tube for simple straight line units. A little more if the tubing is to be bent to fit something. A little less if you buy many at a time. A group buy would great for this. Small diameter CCFL is mass produced and so is available in either straight units or spirals like CFL twister tubes but not in custom shapes unless you're a Hewlett-Packard. Many different "colors" (called color temperature) of white are available with traditional neon tubing. A very pleasant one is 2700 deg K tubing which duplicates the color temperature of incandescent lamps. Warm and comforting. 4-8000 deg K is various shades of "cool white", the higher ones being bluish-white like sunlight. This is good for doing detailed work and reading but it isn't very relaxing. "High CRI" (color rendering Index) white is available for where accurate color comparisons are necessary. Women like high CRI lamps for applying makeup that is to look good outdoors. The "OTT Light" is an example of a commercial product. Such phosphors also usually contain a longwave UV emitter that makes whites pop and text jump off the pages of coated paper. That "high brilliance" paper that the office supply companies sell is coated with a blue dye that responds to this long UV. Under black lighting, that paper is blindingly bright blue! Small tube CCFLs are generally available in 2700, about 5000 and 8000 deg K plus primary colors. CCFL requires a high voltage, low current driver. A 15 mm diameter tube will typically require 400 volts per electrode plus 400 volts per linear foot. Drivers are constant-current devices so it's OK to put fewer feet of tubing than specified on a driver. The voltage per foot goes up as the tube diameter goes down. Drivers can be solid state or traditional coil-and-core transformers. I like C&C for line-operated devices, as they're more rugged, cheaper and don't generate EMI. They are heavy and slightly less efficient than solid state devices and tend to buzz when powered from pseudo-sine inverters. Solid state drivers can be had for anything from 12 volts DC to about 277 volts AC. For mobile use, I like the Tech-22 drivers (http://www.tech22.com) These are small, reliable, dimmable and modulatible (just in case you want your lighting to throb to the music :-) He makes both 12 and 24vdc and 120vac units. Coil and core transformers are usually bought through sign supply companies like Reece Supply, Neon Engineering and Tubelite. I think Tubelite has an on-line store now. Another supplier, West Coast Custom Designs (google for the URL) imports Chicom units that aren't bad. There's a guy in Lubbock, TX that imports ceiling fans from China, of all things, who also imports some nice and very cheap small coil and core units. Small tube CCFLs come either as an assembled unit ready to apply power to or with a matched driver. Linear tubes are widely available both as surplus and for geeks who like to light up their computer cases. I'm pretty sure I posted earlier this year a URL for a company making small tube CCFL lighting fixtures for RVs and boats. I'm not on-line at the moment so I can't look it up. I know that Austin Electronics in Atlanta (770-449-8697) has been selling about 1 ft long small tube CCFLs with the driver, last time I checked for about $12. He has a website now but I don't know the URL. The proprietor is Lloyd Carver, a super guy. Ready-made CCFL lamps are making a traditional ChiCom mass invasion right now. Only available on the web right now; look for 'em at Camp Wallyworld next year :-) They look like CFLs but are lower wattage and have very long lives. Here are a couple of sources of ready-made screw-in CCFLs: http://www.blackenergy.com/store/tcpcoldcathodealamp-p-890.html http://www.buylighting.com/ I have purchased one time from buylighting.com and have been satisfied with the service. I have not bought from blackenergy.com, though I've heard that they're OK. The disadvantage of this kind of CCFL is, of course, that it won't fit very well in the RV environment, at least not with regular size RVs. A couple of years ago I replaced the RV type incandescent 12 volt fixtures in my rig with those ThinLine hot cathode fluorescent fixtures. I'm now going back and replacing the fluorescent lamps and ballasts with traditional neon type CCFLs and Tech-22 drivers. (Maybe I can Sleazebay the ballasts as spare parts :-) There are several reasons. First, the ThinLine ballast, while a quite clever design from a cheapness standpoint, is not regulated, nor is it filtered. That means that the light varies intensity with incoming voltage. Worse, over- or under-voltage rapidly shortens the fluorescent tube's life from sputtering. And with no DC filtering, in those RVs with Magnetek converters that supply unfiltered DC to lighting circuits, the lamps flicker badly AND sputter the lamps quickly. Plus, mine give off significant RFI. The Tech-22 driver is regulated and filtered, is dimmable and generates no flicker. The RFI level is quite low. His dimming technique is clever, involving pulse width modulating the full voltage signal rather than decreasing the voltage drive like traditional neon dimmers. This means that the brightness can be reduced to almost nothing without flicker. I'm putting a U-shaped run of 10mm 2700 deg K (AKA "incandescent" color) tubing on each side of the dual lamp fixture. One driver will run both. When you look at my rig from the outside at night, it looks like it's lit with incandescent lamps. Nice! On the agenda is miniature cove lighting under the cabinets and around the ceilings. For the cove, I'm using thin wall PVC tubing split down the middle and painted to match the interior of my rig. The interior of the tubing is lined with this stuff: http://www.mirrorsheeting.com/ I'm using the double-sided 100% reflective stuff held in with Scotch 77 aerosol adhesive. The highest powered Tech-22 Driver can drive maybe 20 ft of 10mm tubing so one driver can run a whole side's worth of tubing. I'd rather have one driver for each side of the RV rather than have to run high voltage wiring across the ceiling. You've probably already seen my outside neon lighting. There I use 6500 deg Kelvin rare earth TriPhophor (more efficient than the old halophosphate phosphors) tubing encapsulated in thick walled polycarb tubing. The high color temperature results in details being resolvable at lower light levels (things like roots and stobs sticking up to trip you) and makes reading possible at lower light levels. The polycarb tubing protects the glass tubing and contains the heat so that the tube can operate at lower temperatures in the winter. I put a little Xenon gas in these tubes to raise their resistance and generate a little more heat than plain argon/mercury does. One Tech-22 driver runs the whole mess. I made some for my mom's MH that fits nicely under her awning and reflects off the inner surface of the fabric when the awning is extended. >Thanks already for your other very helpful electrical and lighting posting. You're most welcome. This article is of general interest so I'm going to post a copy without your name attached to RORT. > >And good luck with your switch from restaurateur to trucker. Thanks again. I like to change careers every 10 years or so. So far nuclear engineer->software engineer with a detour into magazine publishing->restaurateur with a detour into neon and now truck driver. Who knows what comes next? :-) I have a nice little side practice of power quality and energy audit consulting. If I don't retire completely, that may be next. John |
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