Led lighting

[MyronL]

Myron,

Are you sure about the lablelling on the two pictures?

The one on the left (labelled LED) is far better on my monitor. The one on the right is washed out and yellow.

Exactly. That's the proof, IMHO, that Halogen produces the better light. Left pix is correctly exposed. But using same settings for the right pix the results seen here are way overexposed, by as much as four stops, because its light (Halogen) was four stops brighter than the LED's.

In photography, a "stop" is a term used to define the amount of light entering the camera. Each "stop" allows twice as much light as the succeeding one. So 4 stops translates as 4 times more light, or 4 times less light, whichever way you're going. (All other things being equal.)

Hey Gary, it finally warmed up over 60 degrees one day last week and I got to apply some of that Formula 27 to Burro! Great stuff.

[Steve L.]

Myron,

You mentioned that you're comparing the 24 LED light to a 50W halogen bulb. You're comparing a 4 amp drain for the halogen to a 0.1 to 0.15 amp drain for the LED. People don't go LED for raw brightness, they do it because they're boon docking and they're trying to save amp-hours.

I wondered if you typo'd the wattage of the halogen, but even at 5W you're talking about 4 times the electrical drain.

For my money, LED's are great for boon docking. About half my bulbs are LED and half regular incandescent depending on whether I'm plugged in or not.

[MyronL]

I agree, Steve, the comparison is not fair and the results shouldn't be a surprise to anyone. Two different bulbs meant for two different purposes. Like Gary said.

I only chose what I did because they were the brightest individual bulbs I could find, off the shelf, for my single application. In fact, 6 of the LED diodes faced to the rear, as the seller explained, to give the light more circumference, and that, in my fixture, reduced and distorted the LED intensity.

Right again on the amp drain, but it wasn't germaine to my investigation. I was just searching for the brightest bulb available to compare to an LED in an 1156 base. For sure you boondockers need to count your amps carefully.

[Brian B-P]

Steve has already asked about the same thing I am wondering: what is the power draw of this Myron's test LED "bulb"? Counting the LEDs doesn't mean any more than counting light bulbs, since they come in a wide range of power levels, just like ordinary light bulbs. A popular supplier mentioned in this forum is Super Bright LEDs; they say that their 1156 base white 24-LED unit draws 75 milliamps at 12V, which is 900 mW (0.9 W), but I don't know if this is Myron's unit.

The test conditions for the two photographs are not exactly matched (the halogen has a slightly longer exposure and slighter wider aperature, both of which let in more light), but they're close and the bulb brightness difference is readily apparent, which is not surprising. The specs which I have seen for incandescent, LED, and fluorescent lights generally suggest that fluorescents are roughly 4 times more efficient than an incandescent, and white LEDs are somewhere in between, so I think that it would be wildly unreasonable to expect an LED group of less than one watt to be anywhere near as bright as a 50 W incandescent bulb.

[Brian B-P]

JIMZ asked specifically about LED light sources inside the trailer, but external LED lights have come up as well, and I'll put my two cents in...

As mentioned earlier, LEDs are particularly suitable for producing a single colour of light, which may be one reason that many people are quite satisfied with LED tail lights but not white-light sources. Despite this, I am quite satifisfied with my single-LED 1-watt flashlight.

The more important factor seems to be fixture design. A proper LED tail or turn light is an array of LEDs in a reflector and housing designed for that purpose. The "conversion bulbs" which companies such as Super Bright LEDs sell allow the customer to continue to using their existing fixture, which may be necessary when converting your regular production car, but pointless on commerical vehicles and trailers which use common shapes of lights, such as the round Grote mentioned earlier. Putting a bunch of little directional LEDs in a reflector and lens designed for a single intense omnidirectional source (bulb filament) seems doomed to be unsatisfactory.

Although some school districts may have gone back to the cheapest lights they can buy, all public transit vehicles for a few years in this area use LEDs, which are selected for the cost savings resulting from reduced long-term maintenance, not by energy savings. Traffic lights are going LED here as well: they are certainly as bright and visible, and have the same reliability benefit.

My original Boler taillights work fine, and the marker lights work well enough. It will never be on the road enough to justify LEDs on the basis of bulb maintenance cost, but I would appreciate a lower power draw on the tail/marker light circuit. If I were building from scratch or building the ultimate trailer I would certainly use commonly available commerical vehicle LED lights for all external light functions.

[MyronL]

I bought the LED off a buy it now ebay auction. The seller didn't identify the manufacturer. This is what he did say:

<blockquote>This is a solid-state 1156/24 LED Ultra Brilliant White lamp containing **24** LED's. The 1156 fits most overhead fixtures that are 12 volt to a single contact bayonet base which is ground. The 24 LED version is uniqueand has 18 LED's firing forward and 6 LED's around circumfrance for radial lighting.</blockquote>

Here's his picture of the bulb, which deceived me, I must admit. It didn't look to me as small as it really is. I wouldn't know a milliamp from a candlepower anyway.

[Byron Kinnaman]

Steve has already asked about the same thing I am wondering: what is the power draw of this Myron's test LED "bulb"? Counting the LEDs doesn't mean any more than counting light bulbs, since they come in a wide range of power levels, just like ordinary light bulbs. A popular supplier mentioned in this forum is Super Bright LEDs; they say that their 1156 base white 24-LED unit draws 75 milliamps at 12V, which is 900 mW (0.9 W), but I don't know if this is Myron's unit.

The test conditions for the two photographs are not exactly matched (the halogen has a slightly longer exposure and slighter wider aperature, both of which let in more light), but they're close and the bulb brightness difference is readily apparent, which is not surprising. The specs which I have seen for incandescent, LED, and fluorescent lights generally suggest that fluorescents are roughly 4 times more efficient than an incandescent, and white LEDs are somewhere in between, so I think that it would be wildly unreasonable to expect an LED group of less than one watt to be anywhere near as bright as a 50 W incandescent bulb.

Trying to compare light output by comparing watts of different technologies is a waste of effort. The only time you can really compare light output vs watts is in an incandescent lamp. The amount of current for an LED vs light output does NOT carry to all LEDs. The only real way to compare is by reading the lux, lumens, or candle power.

[Steve L.]

Personally, I can live with the bluish tint of the "white" LEDs, but I would like to read without wearing a headlamp. I find LED's are plenty bright (not halogen bright) but either too diffused or too focused. I'm betting that the future with LED lighting will be with reflectors. i.e. not shining the bulb out wards but back toward a reflector which would do a better job of intermediate diffusion. And, might be user adjustable. Task and area lighting. We'll see I suppose.

I do applaud Myron though for going to the effort. I have about a dozen different style LEDs, different bases and a "cold" fluorescent and have often thought of setting up a test fixture with the bulb set about the distance from my over head to the table top. Fix the camera exposure and photograph an open magazine. Also, record the amps drawn. I'm too lazy I suppose. Perhaps a little later in the winter when I get stir crazy.

Right now I'm working on hooking up a giant rubber band to connect to the trailer wheels to the trailer frame. They'll wind up on the way out on vacation and then unwind on the trip home. Driving the trailer. It'll practically be a free trip home!

Nevermind.

[Brian B-P]

...The only real way to compare is by reading the lux, lumens, or candle power.

Yes, in case I wasn't clear, I was looking to find out a little more about the test unit, not thinking that the power consumption directly equates to light output. For those who recognize the terms which Bryon has introduced, Super Bright LEDs (again we don't know if that's who made Myron's unit) does publish some actual performance data for their LED component parts as data sheets linked to the part numbers in the table on their LEDs page, as do other manufacturers.

A readable description of units of light measurement is available from the Wikipedia; I would prefer to see these interesting light sources (LEDs, cold cathode fluorescents) clearly rated in lumens, just like the ratings on the retail packages of regular light bulbs of most major brands.

Wikipedia also has a section on light source efficacy and efficiency, which I had not seen before today. It gathers information from several sources, again indicating (in really general terms) that white LEDs are typically more efficient than incandescents, but not as good as fluorescents.