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From: Ken James (no email)
Date: Sun Mar 09 2008 - 06:51:04 EDT
Mark on SV Perseverance
we intend to replace the cabin and nav lighting with LED. my web
searches so far have led me to http://www.bebi-
electronics.
com/serving.html They have voltage regulation built into
the bulb aray and offer lights for 12 and 24 VDC systems that are
tollearant of the variation in voltage between charging and running.
the AQUA SIGNAL lights on my boat are identical to the examples they
show. Our system is all 24 VDC.
Reply;
Here is some comparison between methods/approaches;
These lights use a linear regulator, a much better choice than a simple
series limiting resistor, and it does allow easy 24VDC operation
capability, but this is a device that just burns up any power that is of
a voltage above what the LEDS need and turns that power into heat, so
the LED 'driver' they use is not very efficient. This design does not
have nearly as much over-voltage and transient protection as the
FirstStar (which is prob the highest of anyones).
Also they use LEDs that are several generations back and are not very
efficient either, putting out about 80 Lumens per watt while the most
advanced now put out 200+ lumens per watt. To get even close to the same
intensity they must use many, many more LEDs and burn a lot more power.
And clustering LEDs the way they do tends to produce bright and dim
spots, where with a wide beam angle LED with a high power output the
result is a very uniform filling of the illuminated area.
Also the vertical spread of the LEDs they use is only 60 degrees, if
your boat heels more than 30 deg IE a rolling swell or strong wind force
you will disappear. FirstStar uses 140 deg LEDS so even if your mast is
nearly on the water you will still see these lights.
Not only that but for their tricolor light they are using white light
LEDs behind colored filters to get the light for the tricolor function,
not a good idea at all as the result is a low efficiency, dimmer (as
only about 12% of the light in a white light LED is red light, for
example, so to get colors they must start with a LOT of white light!)
and off color confusing masthead navigation light with no way to form
sharp divisions between sectors leading to even more dangerous confusion
when a boat sees you rather wide zone of color sector overlap.
The FirsStar tricolor light uses colored light LEDs and has proprietary
'HyperSheild' light shields on the LEDs that insure a sharp color sector
division with crisp bright edges. It can even be used with a clear
fixture if desired.
Here is what a recent customer who had the opportunity to directly
compare a FirstStar light with these lights had to say;
"Hello, Ken:
All is well (or great!). When I finally got back up the mast yesterday
morning to check the light, I discovered that while I was struggling to
get the light housing back on in 30+ knots of wind after putting the new
lights in, I'd gotten the red/white sectors facing forward, instead of
green/red! When I looked at it last night, it seems like I do need to
twist it a few degrees (The fixtures sockets were twisted-Ken), but it's
pretty close. A friend who's here with his boat, who got lights from
Michael (Bembe) (SP-Ken) in Fiji, turned his tri-color on when I had
ours on, and we walked around and compared them. It's VERY apparent how
much better it is to use colored LEDs, since your's is a greener green
(not the bluish tint) and the red is much more intense.
We had 35-40 knots continuously for four or five days, with frequent
gusts over 50. The mast, rigging, etc. were coated with a
salt/sand/grit "grime", so I pulled a hose up to wash everything down.
I doubt that the masthead lights would have been visible for more than a
few hundred meters as coated as they were. As you'd expect, this
morning it's raining...
Thanks again for all your help. I've given your website url to a couple
people here who saw how good your lights are.
Cheers, Ken (Ken S., On S/V Aquila -Ken from FirsStar)"
I do not make 24V Nav lights, but folks like Orca Green do and their
models, while not retro fit 'bulbs' and being more expensive, are also
more efficient and have the necessary correct color sectors and are bright.
And there are ways to use 12V lights with a 24V system.-Ken
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