by Dennis » Tue Aug 14, 2012 10:40 am
Hello Black Sheep
I have a NASA Tricolour masthead light, which uses the same technology as the NASA anchor light.
My light is very bright, in darkness it would certainly be visible from 2 miles.
However, my light is currently not on the boat it is sitting on my workbench. I noticed earlier in the season that only every other LED was lit. I subsequently removed it from the mast and investigated.
I discovered that the circuit was arranged so that if one LED was defective half of the remainder would remain operational (a good safety feature). I replaced the defective LED and left the unit operating (on the workbench) for 24 hours. Fine, everything was still working after that period. However, subsequently another LED malfunctioned and over the next couple of days a total of 4 LEDs stopped operating (still on the workbench). I realised at this time that the driver circuit for the LEDs was obviously intermittently malfunctioning and exceeding the current limits for the LEDs.
I have subsequently removed the original circuit board and built a new one using slightly different (simpler) technology. I have arranged the LEDs in 10 separate circuits of 3 or 4 LEDs in series with a current regulating IC (20 mA). (32 LEDs, 10 ICs, 10 resistors)
This is the same type of circuit that I used when I made my own LED anchor light which has operated faultlessly.
Basically I am suggesting to you that you may have a (different) circuit malfunction on your anchor light, your light should give full brightness with an operating voltage down to 10 volts.
I found that when operationg correctly, the light was too bright to look directly at with the naked eye, when held at arms length.
Cheers
Dennis
CC19 #100 Mary Ann