http://www.afloat.com.au/afloat-magazine/2008/may-2008/Boat_Electrics_LED_There_Be_Light
What follows are excerpts from this site and my responses. -Ken "Not one manufacturer has been able to obtain certification of their traditional nav lights fitted with an LED insert!" Reply; It was a tough nut to crack, BUT it was done years ago. The firststarled.com MKIV retrofit light DOES have what it takes in every way, but it is not certified due to $ issues (it is very expensive to do and we are a very small company). "You definitely can’t fit a white LED into a coloured nav light because the coloured lens relies on filtering a large portion of the light in order to change the light colour. The resultant loss in light intensity means the light will not be visible for the required distance." Reply; In general this is true, and two more problems not addressed by the author on this site are that of color shifting (many white light led lights for use in tricolor fixtures will produce a very blue green and a feeble orange red due to color shifting by the filters), and an even worse problem is that due to the optics and geometry of the fixture which was designed for use with a normal bulb, while leds do not emit light in the same pattern but in overlapping cones, there will be color sector overlap and color mixing resulting in who knows what color displayed. Also since by comparison only a tiny fraction (less than 5% typically) of the light is absorbed by using colored light leds the unit is far more efficient if that is done. See the tech pages at www.firststarled.com for a more complete explanation of these issues or look up "led anchor light" in wikipedia and then you can also browse the embedded links to learn much more than most would want to know! <G> "Insert lamps don’t last, the fittings are not totally sealed, leading to corrosion problems. Insufficient heat sinking usually leads to premature failure, sometimes after a few hours. The same applies to some cheaper dedicated LED nav lights where LEDs are simply soldered to a PCB and not properly encapsulated." Reply; The solution is to encase and pott the light, use corrosion preventative coatings on the contacts (or use corrosion proof contacts) and proper heat sinking along with active thermal control using thermal feedback. This all costs more but it is needed as these are real problems. A FirstStar MKIII light sat 32 feet down on the bottom of a harbor for several weeks then was retrieved, and was found to still work perfectly. Retro fit lights or "inserts" do present unique challanges that most mfgs do not fully address, but if done properly it can result in a cheaper, lighter weight, more compact, and simpler to install led light. I would add that the leds (3mm and 5mm 'lamp' style) shown on the site are rather old fashioned by todays standard and not nearly as efficient or long lived as better leds today. What's more you can see 'nulls' or dark stripes in the anchor lights 360 deg beam pattern from these old fashioned leds. Newer leds leave no such nulls. _______________________________________________ Liveaboard mailing list [email protected] To adjust your membership settings over the web http://www.liveaboardnow.org/mailman/listinfo/liveaboard To subscribe send an email to [EMAIL PROTECTED] To unsubscribe send an email to [EMAIL PROTECTED] The archives are at http://www.liveaboardnow.org/pipermail/liveaboard/ To search the archives http://www.mail-archive.com/[email protected] The Mailman Users Guide can be found here http://www.gnu.org/software/mailman/mailman-member/index.html
