Next message: markhoenke: "[world-cruising] Re: [World Cruising] LED cabin lights reply... bit windy (WARNING: may be too much info for some)"
Ken James wrote:
> Mark on SV Perseverance
> we intend to replace the cabin and nav lighting with LED. my web
> searches so far have led me to
Try http://tinyurl.com/28hbd4
> 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
