First: My opinion is that regular "white" LEDs are really too blue to use as
the only overhead lighting.
Did a comparison on "warm white" LEDs from Luxeon and halogen light bulbs
from Osram.
There are no warm white leds giving more lumens/watt than the halogen light,
at the best they are equal.
On the other hand a "warm white" LED is probably 50 times more expensive
than the halogen.
And this did not take into account that one needs a resistor in series or
some type of switching supply.
And flourecent lights are much more efficien than halogens.

There are no CE marked LED navigation lights for boats larger than 12m,
wonder why?

Regs/TomS

"Steve Alexanderson"
Idon'tlikegreeneggsandspamIdon'tlikethemsamIamsal
wrote in message ...
So lumens per watt, are they more or less efficient than fluorescents,
including losses in resistors and ballasts?

"Meindert Sprang" wrote in message
...
"Terry Spragg" wrote in message
...

Sorry Terry, but your post contains a lot of mis-information.

The cheapest source for white LEDs at present seems to be salvage
from solar yard lights on sale.

OEMs are buying them all up in bulk, I guess, I have not yet seen
any at radio shack, or even my parts wholesaler catalogues.

White LEDs are commonly available at all major wholesalers.

Each LED consumes about 80 milliamps at 1.6 volts or so.

No. The voltage drop across a LED depends on the color of the LED.
Red LED's drop 1.6V, green and yellow drop appr. 2.0V and blue and white
LED's drop around 3.5V.

But the voltage is not what you apply. You apply a current, which is 30mA
maximum for normal LED's. So, add up all voltages of all leds you have in
the string, subtract it from 13V, devide the remaining voltage drop by
0.03
et voila: your resistor value.

The white LED Lamps (not LED's) are a different beast. These draw a
higher
current and are mostly fitted with a current limiting resistor. Never
assume
a working voltage of these types, always check the datasheet of a
specific
type.

be strung in series so that 5 would require 8.1 volts or so to
ignite, and require a specific resistor in series in the range of a
couple hundreds of ohms to protect the devices from overcurrent, as
they cannot protect themselves or control current in the way we
usually think with ohm's law, as they have conductive
characteristics quite different from resistors, incandescent or
otherwise. More like a gas discharge tube, really.

They're just a diode and like all diodes, they will blow if you connect
them
directly to a voltage source higher than their junction voltage.

Reverse
connection means they just don't conduct or light up unless exposed
to excessive voltage, in which case they melt and fuse to become an
open circuit.

LED's have a very low reverse breakdown voltage of around 5V.

They can be driven from an A.C. source, conducting
like rectifiers.

No, because of the low breakdown voltage. You can either connect two
anti-parallel or of you need only one LED on AC, add a normal diode
anti-parallel to conduct during the negative halve of the AC cycle. This
way
each diode or LED limits the other's reverse voltage to it's own junction
voltage.

Yes, they are much more efficient than regular lamps, consuming
about 1/10 the power for equivalent light output, but, at the
present state of the art, high intensity leds are not really very
bright.

Have you ever stared into a LumiLED without wearing shades...?

Meindert

"TomS" skrev i meddelandet
news
There are no CE marked LED navigation lights for boats larger than 12m,
wonder why?


I know absolutely nothing about CE marking, but the products from this
company http://www.lopolight.com/ seems to have some kind of approval from
the Danish Maritime Authority
http://www.cordland.se/images/Lopoli...20approval.pdf.
According to the homepage of the swedish distributor, this would mean that
it's approved within EU. Part of the approval speaks about ship less than 50
meters.

I need to replace my navigation lights for a 37 sailboat, and the Lopolight
ones look nice. Are there any other manufactureres I should look at?

Thanks,

Jan

"Jan Akalla" wrote in message
...

"TomS" skrev i meddelandet
news
There are no CE marked LED navigation lights for boats larger than 12m,
wonder why?


I know absolutely nothing about CE marking, but the products from this
company http://www.lopolight.com/ seems to have some kind of approval from
the Danish Maritime Authority
http://www.cordland.se/images/Lopoli...20approval.pdf.
According to the homepage of the swedish distributor, this would mean
that
it's approved within EU. Part of the approval speaks about ship less than
50
meters.

I need to replace my navigation lights for a 37 sailboat, and the
Lopolight
ones look nice. Are there any other manufactureres I should look at?

Thanks,

Jan


I suspect it costs more than your boat.....

"Mobey Dick" skrev i meddelandet
...
I suspect it costs more than your boat.....

There is a boat show on in Stockholm this weekend, so I'll check that out. I
have seen a report of about SEK4000:- for a complete set, that would be
around US$560. A lot more than a regular set of lights, but I just wish that
the boat was less than that...

Jan

"Jan Akalla" skrev i meddelandet
...
There is a boat show on in Stockholm this weekend, so I'll check that out.

Prices on the show a

Starboard/port combined SEK 2500 (US$360)
Combined Starboard/port/stern/anchor SEK 3758 (US$540)

The combined one draws 3.9W in sail mode, 2.4 at anchor. For an additional
SEK555 (US$80) you get a special lid where you can mount a Windex, and the
lid also have a small hole that lights up the windex.


Quite expensive compared to regular lights. They claim MTBF more than 50000
hours, and they look very sturdy. The tricolor looks like a nice one to have
for night sailing when you want to save on battery.

Jan

"TomS" wrote in message
news
First: My opinion is that regular "white" LEDs are really too blue to use
as
the only overhead lighting.

I thought that too, but in using them regularly I got used to the bluish
tint and now 'normal' halogen and especially incandescent look downright
yellow, borderline orange in comparison. "White" is in the eye of the
beholder.