LED nav. lights. Has anybody ...

Evadne

Evadne

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.... thought of or tried other technologies?
It occurred to me that LED nav. lights are a typical of a design project that has run up against the laws of physics and is getting ever more complex in trying to get around them.
The real problem is not to get LEDs to work properly but to get more light for fewer amps, so why not fluorescent lamps instead of incandescent. Sure, the savings aren't as dramatic, but 75% (based on household lamps) is still pretty good.

I've had a quick look around (google) and found nothing relevant. The real technical problem will be getting a fluorescent material to transmit significantly in green and red, but then surely that holds true for white LEDs.

Has anybody any experience of these, or should I have kept my mouth shut and rung up the patent office?
 
The great thing about LEDs is that the red and green ones are more efficient than the white ones (which have to use a phosphor to get the wide band). It is not sensible to take a white LED and then filter it to get red and green - you lose efficiency twice. However, that's the way to fit LEDs into existing fittings. To be efficient you start with a new fitting using red, green and white as actually required. There is also no physics reason why they are directional - it's due to the shape of the device.

luminescent lights can also come coloured - again it's a phosphor which takes a coloured light and makes it white.

If there was a mass-market the correct colours, directionality and efficiency would not be a problem at low cost. While the market is new, and small, we'll have to put up with all the problems which people complain of. It's not the physics, it's the market!
 
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LEDs are also very directional, which is not good on a yacht that heels, or rolls in a seaway.

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But, as the other chap said - they don't have to be directional.

It is true that the higher-output devices tend to be directional, but that is only because they have been designed as replacements for halogen spotlights. There are wide-dispersion versions made as well. Most of them are white (which is less efficient), again because of their normal usage. But, again, there are high-output versions in red and green.

The main problem is the regulations themselves, and the interpretation of the regulations. The rules, and the common understanding of them, are based on filament lamps. What is needed is for a manufacturer to demonstrate that the visibilty of their LED nav-lights is equivalent to filament-based lights, to the satisfaction of the MCA, or other recognised body. Until this has been done, and widely accepted, your insurance company will still try to wriggle out of any night-time claims, citing illegal lighting!

The technology is there, it is just everyone else who isn't /forums/images/graemlins/tongue.gif
 
Regulations...

What regulations, exactly?

Is there anything in law tat requires us to use a certain type of filament bulb? I very much doubt it...

If that were the case then oil lamps would be illegal, and I don't believe they are.

In any case, far more important than the filament for dispersion is the lens, does anyone claim there are regulations attached to these too?

The only laws I know about lights are the requirement to show specific colours in specific sectors.

Can anyone point me to the "rules" that say LEDs aren't satisfactory? Cos my nav and anchor/tri LEDs are just as bright as the bulbs they replace, and I can't see any dim spots as I walk around the boat...

Just for info these are direct replacement offset bayonet "towers" with strips of 3 LEDs arranged vertically, and a couple on top.

I've got a suspicion this is another of those urban myths like all the imaginary "health and safety regulations" we cite as reasons for not doing what we've always done perfectly safely before...
 
Can anyone explain directional, in reference to LED's, to the uninitiated (err...me) as my christmas lights don't appear to be different when viewed from any angle. Obviously missed something.......again!
 
Yes. There is nothing directional about the light emitted within the semiconductor. The directionality is all about the angles at which the light can escape from the semiconductor material (which has a high refractive index, for those who remember their physics). It depends on the shape of the device. They are made to be directional as replacements for lights that use reflectors to make them directional (like in torches or halogen lights) - ie in those applications directionality is a plus point. If you then take a whole array of LEDs (each of which are directional, because they were made to be) and set them angled round a cylinder or even sticking out of a sphere, then your problems are over.

By the way, I'm not a chap!
 
Fluorescent nav lights did once exist.

30 years ago I had a small boat with a fluorescent (vertical tube) tricolour at the masthead. Not brilliant cutoff angles but at least I could be seen all night without flattening the battery (and as the boat had no battery charging whatsoever if it went flat the lights went out).

I used to take the battery out of my car when I went off sailing (also helped the car not get nicked when parked for a week or three) and with careful usage (no electronics, a couple of l fluorescents plus oil lamps) could go three weeks and sometimes the car would even start on return when the battery (40AH) was put back in. More often than not though I had to bump-start the car, but I was always careful to park it at the top of a slope!
 
Have a look at Annex 1 of the 1972 COLREGS and subsequent amendments.

You can rest assured when you have an on-the-spot fine levied on you by Netherlands, Portuguese or French authorities, your defence will be ignored.

(Those are the only three that I know have taken direct action, possibly there are others)
 
LED's usually have a lens integrated that beams the light at an angle of 20 degrees. Keeping one LED axis 20 degrees below horizontal and another 20 degrees above horizontal, gives you 40 degrees. 6 such pairs will give you then 120 x 40 degrees.

Colregs (ours anyway) say that such and such a light on such and such a vessel must be visible for 5 miles, or 3 miles or 1 mile. It says nowhere how to get that kind of light. Oil lamps went out a while ago. Pen pushers are just behind their time again. The day will come when LED's are required by law. LED's have a mean failure rate of 1% over 50000 or 100000 hours. This means that out of 100 LED's operated for 100000 hours, one will die. No bulb can last this long. Energy saving lights may last for 6000 hours plus, but will not likely last 10000 hours. So they say.

However, a super-bright LED will draw about 50mA, but there are now super-flux LED's, that draw 350mA and are bright enough for back lighting. These come with a selection of diffusers to choose an angle. The nice thing about LED's is that one can operate 8 or 10 in series, with either a voltage controller or a current limiter (better option) and has the same consumption as driving a single LED. The Super- Flux or high- flux LED's are still expensive, but like any electronic components will come down in price soon.

I have normal bulbs in my 12 volt nav light for the survey, they get changed to 24V bulbs to halve the consumption for night sailing.

In addition to that, I have a tricolour (illegal for my size boat) that I have converted to a 12V/7W energy saving light commonly obtainable here. My argument is, rather use .7 A and have a rather good (but illegal) nav light, than stick to regulations and have empty batteries and no light at all.

I will NOT abide by any regulation that can endanger my safety.

Regards

Ongolo
 
It's mostly been said by others, but it's maybe worth noting that efficient modern fluorescent tubes mainly use "tri-phospher" technology, i.e. emitting 3 almost monochromatic primary colours which combine to make white. There's no reason why they could not be used separately to give monocoloured nav lights (or different coloured sectors of a tri-colour), but there remains the point that a solid state LED is probably always going to have robustness advantage over an evacuated glass tube.
 
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The day will come when LED's are required by law. LED's have a mean failure rate of 1% over 50000 or 100000 hours. This means that out of 100 LED's operated for 100000 hours, one will die. No bulb can last this long. Energy saving lights may last for 6000 hours plus, but will not likely last 10000 hours. So they say.


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Interesting to note that in London the LED traffic signals are reverting to traditional lights because the output of the LED falls off to rapidly and gives issues of uncertain aspects in sunlight. o degrade more Whilst the lamp doesn't fail, its performance appears to degrade more quickly
 
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Interesting to note that in London the LED traffic signals are reverting to traditional lights because the output of the LED falls off to rapidly and gives issues of uncertain aspects in sunlight. o degrade more Whilst the lamp doesn't fail, its performance appears to degrade more quickly

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I'm surprised to hear that - are you sure it's correct? The railways are installing increasing numbers of LED signals and they're apparently very popular with drivers who find them easier to sight.
 
Interesting to note that in London the LED traffic signals are reverting to traditional lights because the output of the LED falls off to rapidly and gives issues of uncertain aspects in sunlight. o degrade more Whilst the lamp doesn't fail, its performance appears to degrade more quickly


When LED's are overdriven to make them brighter, (and I suspect to get the tender for traffic lights they were made as bright as possible), they become walking wounded. In super bright LED's that is 100mA or more, but driven with 50mA, they do not deteriorate, been using LED's in many applications since 1976.

Here truck indicator, stop and tail lights are now universally replaced by LED assemblies.

The trick is, to use current limiting rather than voltage stabilisation. Regulating voltages, one is dependent on constant voltage and constant temperature. Increasing temperature cause avalanche effect of current increase.

I suspect, somebody took short cuts in the driver circuit. Current limiting for LED's can be achieved with any redundant voltage regulator (yes voltage regulator) and two resistors. Any of the following IC's can be used, 7805, 7809, 7812, 7905, 7909,7912, microA 309 or LM309 of the most universal of all, the LM317/LM337 can be used.

In my boat, I have a couple of red (prevent nigh blindness) Led's illuminating the passages and strategic points. I never switch them off, as bright as the first day, none failed. Been on continiously for 7 years now, or 8?? that totals 60000 hours or more. No failures.

Regards


Ongolo
 
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Interesting to note that in London the LED traffic signals are reverting to traditional lights because the output of the LED falls off to rapidly and gives issues of uncertain aspects in sunlight. o degrade more Whilst the lamp doesn't fail, its performance appears to degrade more quickly

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I'm surprised to hear that - are you sure it's correct? The railways are installing increasing numbers of LED signals and they're apparently very popular with drivers who find them easier to sight.

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Yep... I shouldn't admit this here, but I work for (ahem) an "executive body" of the GLA responsible for Transport....

Just going,won't be back..... /forums/images/graemlins/confused.gif
 
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There are several suppliers of LED navigation bulbs that met teh Colregs requirements.

see http://www.ledshoponline.com/FLUX_masthead_lights.htm

for example or
http://www.bebi-electronics.com/specs.html#COLREG

The technology works , just accept it

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Whether you like it or not, there is a difference between "claiming to meet Colregs" and "approved as meeting Colregs". Before I buy any LED light, I want to know who approved it and the number of the approval certificate. No approval, no sale.
 
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