Re: LED info Reply #25 – January 28, 2013, 11:29:03 am Yahoo Message Number: 136472Thanks for the correction. On insulating the strips from the reflector, Andy recommends routinely adhering strips of shipping tape to the reflector to ensure insulating the strips. Wouldn't that be a "best practice", regardless of the appearance of the paint on the reflector?Ted
Re: LED info Reply #26 – January 28, 2013, 08:03:57 pm Yahoo Message Number: 136480QuoteOn insulating the strips from the reflector, Andy recommends routinely adhering strips of shipping tape to the reflector to ensure insulating the strips. Wouldn't that be a "best practice", regardless of the appearance of the paint on the reflector?Ted Well, here's the deal on that - LEDs generate a very small amount of heat, compared to other lighting devices. However, the active area of the devices is very tiny, creating an area of high heat density, i.e. high temperature. As solid-state devices, temperature is the enemy, which means providing a good heat conductor at the device active area is vital. Now the devices themselves are designed to sink heat away from the active area, which then is drawn away by conduction through the adhesive tape and mounting surface, and by air convection. Adding an additional layer of thermally poor conductor beneath the strip - such as shipping tape - will allow the devices to run at a higher temperature, which could reduce their lifetime. As a practical matter, I don't know how serious an issue this is, but another benefit of reflector mounting IS the thin paint layer, providing electrical insulation without excessive thermal resistance. Mounting the devices directly on the fixture aluminum frame would require providing some sort of insulating layer, like tape.Steve
Re: LED info Reply #27 – January 28, 2013, 08:15:47 pm Yahoo Message Number: 136481"I don't know about the size of the soldering iron tip. I ordered the red butane one from Radio Shack that Andy uses (see Eureka!). Hope that will work." The butane-powered iron from Radio Shack (part #64-2188) has a narrow, conical tip that will work just fine for this kind of soldering. Keep the iron's power setting between low and medium; the copper foils on these LED strips are pretty thin, and are easily separated from the substrate if you overheat them. But don't worry--if that happens (as it did to me when I was doing my first conversion), you can simply solder your wires to a different area of the strip. Any exposed copper trace on that side of the LED strip is fair game.Andy Baird http://www.andybaird.com/travels/
Re: LED info Reply #28 – January 28, 2013, 08:20:50 pm Yahoo Message Number: 136482"clean the reflector thoroughly with rubbing alcohol before sticking the strips down, and note if any paint is missing under where the strips will be mounted. Bare metal can short exposed contacts." As Ted mentioned, an easy way to ensure this doesn't happen is to lay down a strip of clear 2" wide packing tape on the reflector, and then stick the LED strips to that.Andy Baird http://www.andybaird.com/travels/
Re: LED info Reply #29 – January 28, 2013, 10:01:46 pm Yahoo Message Number: 136485Here is a video that shows how to by-pass the Ballast and how the strips go in the light. http://www.youtube.com/watch?v=HlDGW2lPUkU
Re: LED info Reply #30 – January 29, 2013, 11:10:00 am Yahoo Message Number: 136488Thanks again, Andy and Steve for further guidance. I get nervous when the experts disagree, so try to take a middle ground. In the absence of any objection, I am inclined to apply very thin, clear pressure sensitive tape (not reinforced) to ensure insulation while minimizing (I hope) resistance to heat dispersion. We'll see how it goes when I get the materials. Will report back. Perhaps my amateur's experience will help other amateurs hesitant to try this. On the other hand, my experience may lead them to reaffirm their hesitancy. We'll see.Ted
Re: LED info Reply #31 – January 29, 2013, 12:16:37 pm Yahoo Message Number: 136489QuoteThanks again, Andy and Steve for further guidance. I get nervous when the experts disagree, so try to take a middle ground. In the absence of any objection, I am inclined to apply very thin, clear pressure sensitive tape (not reinforced) to ensure insulation while minimizing (I hope) resistance to heat dispersion. We'll see how it goes when I get the materials. Will report back. Perhaps my amateur's experience will help other amateurs hesitant to try this. On the other hand, my experience may lead them to reaffirm their hesitancy. We'll see.Ted Another option - When making cabinet lights using 3-LED strips, I made a mount from lengths of aluminum u-channel. I then lightly spray-painted the inside of the bare channels with white Rust-o-leum enamel before sticking down the strips. No problems, but give the paint a day or so at room temps to cure before attaching the strips.Steve
Re: LED info Reply #32 – January 29, 2013, 07:07:59 pm Yahoo Message Number: 136497I don't think you need to worry about heat sinking. The LEDs are used in many situations with no heat sinking, such as the 28 5050s on the bayonet bulb replacements I use, or on the 5050s mounted in arrays on circuit boards. They are spread out a lot more on the strips in the fixtures than in the bayonet bulbs and boards, so should cool better. The thin tape will not impede the cooling significantly.Eric Greenwell
Re: LED info Reply #33 – January 29, 2013, 09:04:36 pm Yahoo Message Number: 136498Thanks, Eric. Now I can proceed with less trepidation. BTW, could you provide a link to your source for the the bayonet-mount bulbs (I assume 1141s)? What are the lumen and kelvin ratings? Thanks--Ted
Re: LED info Reply #34 – January 30, 2013, 08:25:51 am Yahoo Message Number: 136500QuoteI don't think you need to worry about heat sinking. The LEDs are used in many situations with no heat sinking, such as the 28 5050s on the bayonet bulb replacements I use, or on the 5050s mounted in arrays on circuit boards. They are spread out a lot more on the strips in the fixtures than in the bayonet bulbs and boards, so should cool better. The thin tape will not impede the cooling significantly.Eric Greenwell Actually, those devices ARE on heat sinks - the circuit boards. While you might not think of fiberglass as a good heat conductor, it is still better than the thin tape of the strips. Remember, the amount of heat is not great - it simply needs to be conducted away from the active area of the device rapidly. Once the heat has spread out and the active area heat density is low enough, air circulation should be adequate. Having to address the issue of heat dissipation while designing small laser and LED mounts in my former career, I am pretty familiar with this topic. A good test - which I have not done - would be to use a remote IR thermometer, off-axis, to monitor temperature of the devices mounted and unmounted. Of course the reading will not be accurate with an inexpensive thermometer, since the active areas are too small, but a relative idea of heat-sinking success is still useful.SteveSteve
Re: LED info Reply #35 – January 30, 2013, 09:58:26 am Yahoo Message Number: 136501Hi Ted, I tried two styles, both were available in warm white (looks like the tungsten bulb) and cool white (brighter, cheaper, but almost bluish white). This one with 36 LEDs, which is indistinguishable from a tungsten bulb in color and intensity when it's in the fixture, cost $6 at the time, but doesn't seem to be available now - 3000K/200 lumens: BrightChoice LED BA15s Bayonet Base 36LEDs SMD Bulb - 2nd Generation with 36 LEDs - Replacement for #1156 1141 1073 1093 1129 93 - Warm White Color : Amazon.com : Automotive http://www.amazon.com/gp/product/B008XB9BJY/ref=oh_details_o06_s00_i01> The other style has 66 LEDs and is noticeably brighter than the tungsten bulb, but is more expensive - 3000k/300 lumens : The Brightest Ba15s LED Light Bulb Replacement - 2nd Generation with 66 LED's - Single Contact Base - 10-30V DC - Warm White Color : Amazon.com : Automotive http://www.amazon.com/gp/product/B009DRJ16U/ref=oh_details_o05_s00_i01> In the dual bulb fixtures, I used one cool and one warm, which gives a light color I like; single bulb fixtures, I used warm white; the outdoor porch light, I used the cool white because it was the cheapest at the time. As you can see, these have the LEDs very close together, with no real heat sink, and intended to be used in fixtures with small air spaces compared to the florescent fixtures. I assume that if they can handle the temperatures they generate in those conditions, the strip LEDs in the florescent fixtures will have no problems, whether they are mounted directly on the painted metal, or have a strip of tape between them and the painted metal.Eric Greenwell As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
LED info Reply #36 – January 30, 2013, 10:34:45 am Yahoo Message Number: 136502Good points. I'm going to be tearing out the cool white strips in our dinette light fixture in order to replace them with warm whites. Since I'll have two extra 16" strips of 24 LED diodes, rather than throw them away, I figured I could jury rig some simple outdoor Chinese lanterns. Originally, I was just going to fold the strips in half to create 2-sided 8" strips of 12 LEDs per side. After reading your message, I'm going to get a thin piece of alum channel in which to apply the strips on either side. Besides, it will make the strips hang perfectly straight inside the lantern itself, instead of curling to one side or the other. As for wiring, I got 20' of 18g lamp wire for $.40/ft. I used a butt connector to crimp on a 2 amp in-line fuse and soldered on some alligator clips to hook to the coach battery. Each strip draws .5 amps, so the two lanterns will draw 1 amp.K
LED info Reply #37 – January 30, 2013, 10:34:52 am Yahoo Message Number: 136503Good points. I'm going to be tearing out the cool white strips in our dinette light fixture in order to replace them with warm whites. Since I'll have two extra 16" strips of 24 LED diodes, rather than throw them away, I figured I could jury rig some simple outdoor Chinese lanterns. Originally, I was just going to fold the strips in half to create 2-sided 8" strips of 12 LEDs per side. After reading your message, I'm going to get a thin piece of alum channel in which to apply the strips on either side. Besides, it will make the strips hang perfectly straight inside the lantern itself, instead of curling to one side or the other. As for wiring, I got 20' of 18g lamp wire for $.40/ft. I used a butt connector to crimp on a 2 amp in-line fuse and soldered on some alligator clips to hook to the coach battery. Each strip draws .5 amps, so the two lanterns will draw 1 amp.K
Re: LED info Reply #38 – January 30, 2013, 11:12:59 am Yahoo Message Number: 136504Quote"clean the reflector thoroughly with rubbing alcohol before sticking the strips down, and note if any paint is missing under where the strips will be mounted. Bare metal can short exposed contacts." As Ted mentioned, an easy way to ensure this doesn't happen is to lay down a strip of clear 2" wide packing tape on the reflector, and then stick the LED strips to that.Andy Baird Clear packing tape may not be a good long term option, as it's durability can be iffy - - On older tape jobs I've seen the clear layer come cleanly away from the adhesive layer (which leaves a hard residue behind that's akin to concrete). In any case, the LED strips I used already have a thin layer of '3M' tape for mounting. I cleaned the reflectors with alcohol and then used hot melt glue for strain relief under the ends of each strip and also to tack down the wiring.bumper[Non-text portions of this message have been removed]
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Topic: LED info (Read 37 times)
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