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Car Forum / Driving, Maintenance, Tuning / Driving / May 2008are any LEDs any good?
Hi all, in the interest of satisfying my curiosity, I was placing an order for some cheap Chinese crap that I couldn't find anywhere else from dealextreme, and figured I'd see if there was anything else that tickled my fancy since everything on the site was so damn cheap. I ended up buying a couple packs of LED automotive light "bulbs," one 1157 red and one 1156 amber (the latter was a mistake; I was thinking of using them in the Stude, and I didn't notice that the amber version was an 1156.) I remember a couple years ago I bought a pair from superbrightleds and they lasted about 5 minutes in my car because they were such a disappointment. Very dim and narrow viewing angle. In a word, crap. This time around, things are not so clear cut. The ones I got had (I think, without looking it up) 45 LEDs; I think 12 or 13 on the end and the rest mounted radially. This resulted in a light pattern closer to a regular incandescent. I mounted one of the 1156 ambers in the rear turn signal of the Porsche, and fired up the hazards. The LED actually looked really, really good - better, in fact, than the incandescent - and the very smooth light pattern and fast rise time made it really tempting to leave it in there. However, overall brightness was still noticeably dimmer than the regular P21W on the opposite side. I do see that there are "57 LED" versions available from various vendors - probably from the same factory in China - and there are other options, like single 3W Luxeon wide-angle LEDs and round LED clusters. Question is, I've been googling my little fingers off, and I find lots of hype and not a lot of data. Are any of the current LED "bulbs" worth spending the $$ on, or are my only options for brighter taillights either the halogens that I've been using (the heat bothers me, we're talking about 50 year old plastic lenses here) or a scratch built LED circuit board? The stock taillights on the Stude are a little dimmer than I'm comfortable with even with a 12V alternator and a standard 1034/1157 bulb. If there were any really good ones out there, I'd be sorely tempted to buy them for all my cars. The fast rise time alone could save your butt from an inattentive tailgater... One thought I had was buying a pair of those standard oval big truck taillights and using the naked circuit board in the Stude taillight housings... think that'd work, or just look like butt? nate  Signaturereplace "roosters" with "cox" to reply. http://members.cox.net/njnagel The light fixtures on most cars are designed to work with lamps that emit light in a uniform spherical pattern. They include a reflector and refractive lens optimized for this pattern. LED typically emit light through a narrower beam angle and, as a result, require optics designed specifically for them. Most (if not all) LED bulb replacements do not properly emulate an incandescent lamp's characteristic pattern and, as such, do not work well. LEDs do work well in fixtures designed to use them. SignaturePaul Hovnanian mailto:Paul@Hovnanian.com ------------------------------------------------------------------ How do I set a laser printer to stun? > The light fixtures on most cars are designed to work with lamps that > emit light in a uniform spherical pattern. They include a reflector and [quoted text clipped - 6 lines] > > LEDs do work well in fixtures designed to use them. I understand your point, I bought the ones I did specifically because they appeared like some thought had been given to that issue. They looked like this: http://www.virtualvillage.com/Items/002510-120?sck=11408822&caSKU=002510-120&caT itle=2X%2057%20Amber%20LED%201157%20Bulbs but with one fewer "stack" of radial LEDs. I don't have instrumentation to measure precisely, but based on simple visual observation their main drawback was simple overall brightness. The light actually filled out the lens very nicely so that it almost achieved the goal of having the light appear to be a uniformly glowing piece of plastic rather than being illuminated from behind. If they were brighter I would have left them in and bought more. I guess I was expecting to be disappointed but was curious enough to give them a try, and they were almost acceptable and that's made me wonder if an actual viable product has been made yet. It'd be really great if I could get some LEDs for the truck also, as I've got a dome light in the camper shell which is powered off the parking light circuit so until I get a wild hair up my butt and run a +12V wire to the back of the truck (which will probably be about the same time that I run a wire for a trailer brake controller) low current draw would be a real selling feature there. nate Signaturereplace "roosters" with "cox" to reply. http://members.cox.net/njnagel > The light fixtures on most cars are designed to work with lamps that > emit light in a uniform spherical pattern. They include a reflector and [quoted text clipped - 4 lines] > bulb replacements do not properly emulate an incandescent lamp's > characteristic pattern and, as such, do not work well. I have modified LEDs to flood rather than spot, for a small aircraft panel lighting application. The end of the LED is usually hemispherical, which focuses the light to that familiar narrow angle, Grinding that hemispherical end flat will allow the light to spread out nicely. Leaving it with the sanded surface diffuses it; I didn't try polishing it to see what it would do. Dan > . The end of the LED is usually > hemispherical, which focuses the light to that familiar narrow angle, > Grinding that hemispherical end flat will allow the light to spread > out nicely. Leaving it with the sanded surface diffuses it; I didn't > try polishing it to see what it would do. That's pretty sharp thinking. I think I'll try buzzing down this 1156 replacement that's been sitting in my desk drawer and see what happens. A pad sander should make quick work of it, as they all stick out very evenly. (The graphical security code for this posting in Google Groups is "sperse" -- shoulda been "disperse"!) --Joe > One thought I had was buying a pair of those standard oval big truck > taillights and using the naked circuit board in the Stude taillight > housings... think that'd work, or just look like butt? I've been thinking about getting a hitch-cover brake light the next time Harbor Freight has them on sale for $4.95. They have some now that are full of seriously big LEDs. I'd mine the LEDs off the circuit board and sort of jelly-mount them in Shoe Goo or clear Polyseamseal. My intended use for this is not taillights but the third brake light, which in most of my cars mounts the bulb transversely -- therefore I don't get much brightness. What I really want from LEDs in this position is the much faster risetime, so that the guy in the Suburban behind me with the latte in one hand and the phone in the other will realize sooner that I'm braking and won't hit me as hard. That's perhaps one reason (along with easier integration into a tricky-shaped body unit) why LEDs are often found in the factory "center high-mount stop lamp" of cars that use regular bulbs in the other positions. The ones in trucks and buses are usually not replacement bulbs of the 1157 et al. variety, but a whole unit that is a drop-in replacement light fixture of the standard sizes and shapes used in such vehicles. (Significantly, most or all of the LED replacement "bulbs" I've seen are not DOT approved, and strictly speaking are not for street use.) As others have mentioned, the truck taillight's innards are optically optimized for use with LEDs, and you might have to do some LED position and angle tweaking to get a comparable result in your taillight housing (rather than just putting the whole circuit board in there, square on). The extent to which it makes your butt look fat depends on the extent to which the taillight lenses are transparent rather than translucent. On a car old enough to have glass back there, you will just have to try it and see. My proposed applications are better diffused and it's harder to resolve the point source(s) of the light. Finally, note that LEDs use less current than incandescent bulbs (and for sure run incredibly cooler than halogens) but do not use zero current as is widely assumed. Put in enough of them and you're right back where you were in current draw, though proper wiring of a tow vehicle is the "right" way to solve THAT problem. Cheers, --Joe > My intended use for this is not taillights but the third brake light, > which in most of my cars mounts the bulb transversely -- therefore I > don't get much brightness. What I really want from LEDs in this > position is the much faster risetime, so that the guy in the Suburban > behind me with the latte in one hand and the phone in the other will > realize sooner that I'm braking and won't hit me as hard. How much of difference would the rise time of a LED be compared with a tungsten bulb? Does a few tens of milliseconds make that much difference? I remember seeing a design on the British inventions programme "Tomorrow's World" about ten years ago for a controller that flashed the brake lights a couple of times before putting them on permanently if the car braked very hard, because flashing lights tend to be more attention-grabbing than steady ones. Peugeot (and maybe othe manufacturers) have a similar device which flashes both rear indicators in this situation. One of the factors that could make a difference is the separation of indicator and brake light bulbs on American cars. When my sister and her family lived near Boston, my parents and my sister were rear-ended by a car that failed to appreciate that her car was sitting in the middle of the road indicating to turn left into a side road and with the brake lights on. The driver said that he hadn't seen the indicator because of the brake lights and so had thought she was slowing down rather than actually stationary. In the UK *all* vehicles have separate indicator lights, distinct from the tail and side lights rather than using the same lens/bulb. Mind you, I can remember a few British cars having the American-style combined lights in the mid sixties when I was a young child. Why is it, though, that the modern trend is to fit clear lenses and ornage bulbs in the rear cluster, instead of orange lenses and clear bulbs? After all, you don't get clear lenses and red bulbs for the brake lights. >> My intended use for this is not taillights but the third brake light, >> which in most of my cars mounts the bulb transversely -- therefore I [quoted text clipped - 29 lines] >bulbs in the rear cluster, instead of orange lenses and clear bulbs? After >all, you don't get clear lenses and red bulbs for the brake lights. Some cars in the US have the seperate indicator and brake light and some have the combined system, many times even within the same make/model. For instance I have two Ford Pouruses. One a 1996 model (seperate orange indicator and red brake lights) and the other a 2000 model (the brake light and indicator combined in one red light). FWIW, both are clear bulbs and the lenses have the color. I can't even begin to fathom why the manufacturers have to do that - seperate brake/indicator some years and combined in others or the colored bulbs and clear lens. -- "That's interesting. I hadn't heard that. ..." --George W. Bush on the prospect of US$4.00 gas >>>My intended use for this is not taillights but the third brake light, >>>which in most of my cars mounts the bulb transversely -- therefore I [quoted text clipped - 44 lines] > "That's interesting. I hadn't heard that. ..." > --George W. Bush on the prospect of US$4.00 gas I think the colored bulb/clear lens thing is just a style thing. Reduces the number of colors in your light cluster from three to two and looks cleaner. I like the look, myself. As for the rise time thing, the difference is noticeable and dramatic when you have the two side by side. nate Signaturereplace "roosters" with "cox" to reply. http://members.cox.net/njnagel << snip >> >> I can't even begin to fathom why the manufacturers have to do that - >> seperate brake/indicator some years and combined in others or the [quoted text clipped - 7 lines] >Reduces the number of colors in your light cluster from three to two and >looks cleaner. I like the look, myself. I guess its a matter of personal preference. Nothing against the colored bulb/clear lens, I just think that the colored lenses look better. But the part about combined brake/indicator in some years and seperate brake/indicator in others is what goes over my head. Personally, I wish that all the manufacturers would pick a standard (preferablly seperate indicator/brake) and stick with it. It would reduce a bit of confusion, IMO. >As for the rise time thing, the difference is noticeable and dramatic >when you have the two side by side. I've noted the difference in rise time on vehicles with the LED lights - usually newer trucks or school busses around here. Personally, the new LED lights seem to be brighter and more notiicible compared to the incandescent bulbs. Maybe they will make replacement LED bulbs for older cars like my Porouses? -- "When you can't afford the gas to drive to the job that you are fixing to lose to pay for the house you can't afford... That's pretty much the recession tri-fecta..." --Jay Leno > << snip >> > [quoted text clipped - 19 lines] > seperate indicator/brake) and stick with it. It would reduce a bit of > confusion, IMO. Well, ECE countries require the separate red brake/tail lights and amber turn signals. So this isn't an issue most places outside the US and Canada. I do agree that the amber function is better but so long as it's not *required* and stylists like the all-red look... >>As for the rise time thing, the difference is noticeable and dramatic >>when you have the two side by side. [quoted text clipped - 4 lines] > incandescent bulbs. Maybe they will make replacement LED bulbs for > older cars like my Porouses? That's kind of what started this thread was a search for something like that. There already are products that claim to be just that, but for the most part they aren't very good. I was wondering if there were any exceptions. nate Signaturereplace "roosters" with "cox" to reply. http://members.cox.net/njnagel > Hi all, > [quoted text clipped - 44 lines] > replace "roosters" with "cox" to reply. > http://members.cox.net/njnagel Have you checked at Digi-Key? They do not carry crap, and last time I looked they did carry some LED based incandescent replacements. The LEDs I got from them to replace the incandescents for the button lighting in my truck radio are still doing wonderfully. I also have a couple 6W Luxeon LED based dive lights that are blindingly bright. Pete C. > > Hi all, > [quoted text clipped - 52 lines] > > Pete C. this is what they sell: http://www.sunbriteleds.com/images/pdf/SSP-1157B156U12.pdf listed as 15.6/4.7 "cd" over a 30 degree viewing angle if I am reading this correctly. A regular 1157 bulb is rated at 32/3 MSCD and should be an effective viewing angle of over 200 degrees. This is why I'm searching to see if there's anything better out there... I guess this is definitely a niche application and the quality of "bulb replacements" is lagging LED development because manufacturers are waiting for the price of newer, brighter individual LEDs to come down before updating their "bulb" designs. nate > ... > listed as 15.6/4.7 "cd" over a 30 degree viewing angle if I am reading > this correctly. A regular 1157 bulb is rated at 32/3 MSCD and should > be an effective viewing angle of over 200 degrees. This is why I'm > searching to see if there's anything better out there... What you are asking for is what companies such as LEDtronics specialized in for over 20 years. Generally this company and its few competitors will always offer the best solution technically possible. See: http://www.ledtronics.com/ds/aut1157/ > Hi all, > [quoted text clipped - 9 lines] > they lasted about 5 minutes in my car because they were such a > disappointment. Very dim and narrow viewing angle. In a word, crap. The retrofits that are basically "a bunch of LEDs on a base that fits in an 1157 socket" are, uniformly, crap. That said, there are a number of vendors of good, regulatory-angency approved on-highway LED lights now (Truck-lite.com, is one). They're made for trucks and trailers and come in standardized packages, but if you can make one fit in a vintage housing, they generally work well provided they don't wind up recessed too deep in the fixture. |
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