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Old 11-11-2004, 15:09   #16
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IMHO you are over complicating the light. You are adding two possible failure items to the top of your mast that could easily be fitted as a separate package elsewhere, - the daylight switch off, and the motor on/tricolour off.

Just how narrow are the beams?
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Old 11-11-2004, 23:16   #17
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Back to the LED part. Firstly, I dunno about them ever replacing a light bulb. Maybe, but somehow I doubt it will be the LED that we presently know of.
The reason why an LED can look bright, but not actually be bright is complex.
The "water clear" generation we have today are different to the older generation of coloured LED package. The water clear packages use differeing elements to gain the colour. These "seem" to be brighter because of several reasons. Firstly, the package being clear, allows more light to pass through it. Additional to that, but a little more complex, in an old coloured package, the light produced was white. White light is broad spectrum. Thus the coloured package filtered a lot of the unwanted light, allowing only the colour of the package light to pass through it. This results in less light energy radiating away. The clear designs produce only a light of the wave length it was designed for. So thus, all the electrical energy producing the light, goes into that one specific clour. Hence the water clear packages seem to be brighter than the older coloured ones. OK.
Now why I commented above about the lightbulb part is for the following. All LED's, no matter what physical size, take close to ruffly the same amount of power to produce the light they do. The differences of power consumption between them are due to the materials used to produce the light spectrum. Some require more current, some require more voltage, blah blah, but all in all, about 100mW @ 2V is the middle ground for most. Some will take very little and some will take upto 130mW @ 4V. The most I know of, is a red one that can max at 135mW at 5V and produce 20,000mcd. But here is the next tricky part.
The view angle. So all LED's are ruffly the same power consumption, and ruffly the same light output. So how do you make them brighter? you take all the light energy and focus it into a beam. The tighter the pattern, the brighter it seems to us. It's not really any brighter, just more photons get to arrive at our eyes, instead of being scattered into space. The really bright LED's are usually the tightest patterns. About 15 degrees is the tightest and figures of 10,000 mcd and more, are usually 15 to 20 degree tight patterns. So this means you have to have a lot of LED's around in a circle to get a good 360 pattern.
You will also notice that the good expensive light units, like Hella and aquasignal, have a focused lens that takes a lot of the light that would have radiated vertically and focus into a horizontal pattern, thus making the light travel further for the given candle power of the bulb.
And finally, although not really as importantly,
The colour, and what we can register with our eyes. Certain colours are harder to see than others. Dark blue and dark red being the extreme ends of the light spectrum, make it hard to distinguish. So you need more light intensity for us to "see" it. Blue is very difficult for us to focus on because of the very short wavelength and Red because of the very long wave length. Beyound those wavelengths, the light energy enters into ultraviolet and respectively, infra red, niether of which we can detect with our eyesight.
And to end, it is also interesting, that even white light can be made up with certain other wave lengths being a dominant background. This is often the case in gas discharge types like flourescent light. Those long tubes can come in all sorts of colour backgrounds. There is one that is a hot white. It has a lot of blue spectrum in the white. It seems very bright and very white, yet it is very hard to see anything when trying to read for instance. A bad light type to have in an office. So often in offices, you mix the tubes with a cool white as well. That has a lot of red spectrum in it and softens the harsh tube. Then you can add a yellow spectrum and that makes a better reading light and so on.

I have tried to keep this easy to understand, not so much techincally accurate. So please don't anyone get nit picky with the above. I am sure I have bored many already.
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Old 12-11-2004, 04:26   #18
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Beam angles ?

Ye Gods . What were they now? Seems that I remember them being about 20 degrees. I was going to place them equaly in a two level stack. I fiqured that the beams would intersect a few feet away from the light. They would also be tipped a few degrees above and below horizontal . The daylight/ off feature was so that I could leave the boat for a few days and the anchor light would be taken care of. Was going to attach a solar panel to a dedicated battery for power to the anchor light. The powering /off feature was to make it more----ummmm, how can I be polite?--forgiving to the memory challenged, yah, that'll work, so the memory challenged would'nt have to remember to turn it off when motoring at night. You can increase the amount of apparent light given off by an LED by voltage pulsing it according to some, but I thouht I'd stay away from that complication, and just see how simple yet usefull I could make this thing. Think I'll give an e-mail shriek to Ken above and see what he can come up with.
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Old 12-11-2004, 08:51   #19
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Wasnt trying to disuade you from your auto shitch, merely making the point that it would be better as a separate item, than a part of the LED.
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Old 12-11-2004, 11:16   #20
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Yeh I ain't trying to put you off either. There are advantages as well. Some LED's will last 100,000hrs. The LED will out last the boat
The part about more voltage blah blah making it brighter blah blah, Sorry Wrong. LED is a Current dependant device. NOT voltage. The semiconductor material excites free Photons in the material selected to provide the colour, when a current flows through it. The LED then becomes a resister. The combination of current and resistance when it reaches it's peak performance equates to a voltage of approx 2.6V. But that is technical and I don't want to bore or sound like a nerd
But the important part, is that a LED will produce only so much light. After that, the LED produces excesse heat. As the heat increases, the light output decreases and also the life expectancy dramaticaly decreases.
But for one last thing. I am not intendeing to put you off the idea. There are advantages. But it is important to know that if you have a vessel that is required by law to have a certain light output, then so far, the LED devices won't do it.
If you want a light sensitive on/off feature, that can still be done with a standard bulb. And as Talbot said, put that device and the regulater down in say the switch board where you can easily access it and the LED where it normally goes.
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Old 12-11-2004, 14:47   #21
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Wheels,

I reluctantly have to disagree with you over the issue of the LED achieving the required brightness. Tests have shown for example that the LED insert by orca green designed for the aquasignal 25 lights, more than achieves the 2mile requirement for vessels under 20m, this is for a light that is designed for vessels under 12m and has a certified requirement for only 1m.

Perko and Hella both have LED nav lights that have met the USCG testing requirement for vessels under 20m (i.e. 2m vis)
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Old 12-11-2004, 15:36   #22
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Yes true, but have you seen the price. As I said in my first post (I think) and I will re-phrase it. If you want to meet the relavent requirements, it gets expensive and you defeat any power saving. As I also said, the only benifit is the fact it can last 10,000 hrs and more, depending on how hard they drive the thing. So you don't have to go up a pole to replace a bulb. But so far, the most econimical light that has good visability is still the trusty ole filiment type bulb. And heck, if ya can't run 20W all night, ya need to look at the battery supply I reckon.
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Old 13-11-2004, 05:26   #23
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Quote:
if ya can't run 20W all night, ya need to look at the battery supply I reckon
Save 20 amphrs here and 20 amp hrs there, and pretty soon you have a real saving!

From my calculations 10 hrs of a 25w bulb are pretty close to the same power requirements (in UK) for a fridge. I would rather have an electric fridge than my present gas one, so had been looking for the area that was easiest to make some reasonable savings - The Tricolour/anchor light is the most obvious one.
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Old 13-11-2004, 11:24   #24
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Yeah but this is where we keep going round in circles. Now I stand to be corrected always. Hey, technology is moving and changing so fast, only a fool would say it "can't" be done. Plus I am far from a Know everything. So Could you tell me, do Hella and Aqua signal have an LED light that gives the required light output and yet uses LESS power than a standard bulb? And I mean substantially less.
Because as I understand it, the present situation is, they have to have so many LED to do the job, that with the No. of LED's and the loss in the regulator, there is little to no saving in power for the same light/distance/360 and so on. Thus my comment on cost versus light output versus yadda yadda versus a standard bulb. And also, don't get me wrong here either, Personally I would rather have LED up the pole and not have to worry about changing the damn thing. But here in NZ, those Aquasignals are something like NZ$250'ish and I like most cruisers, have short arm syndrome. They don't reach the bottem of the pockets where that kinda dosh tends to settle.
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Old 13-11-2004, 13:31   #25
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Having had a quick look at the different ones available today, The tricolour from Orca Green is a USCG certified light for vessels up to 20m.

The light draws 0.5amp (i.e. 25% of that drawn by a conventional bulb)

Cost at US$239 is comparable with UK prices for a tri and anchor combo, however, this one will work with just a 2 wire connection, and a switch to reverse polarity , you can also get it with a photodiode for auto switch off, and with a strobe light.

I have no connection with this company, but like what they have been developing,
of course if they would like me to test one of these for them, I wont turn it down
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Old 26-04-2008, 21:54   #26
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Lopo light Lopolight Navigation lights LED based info@lopolight.dk tel: +45 3248 5030 also has USCG apporved LED lights. I am very impressed with the construction. Yes the are expensive. When I outfitted my boat I put the tri, anchor and windex light on the mast head. Nice small unit. They offier the housing in carbon also. They now have a unit with a strobe.

Mike
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