NASA Supernova Tri-colour and Anchor LEDs

A zener isn't much use without a fuse as it works by shunting current to prevent the voltage from rising. I wouldn't recommend fitting one, as the unit should be protected in the first place, but if you must, fit it with the anode connected to the positive supply and cathode to the ground. Make sure it is capable of passing more current than any fuse or breaker protecting the circuit.
 
There is already a zener diode in the NASA unit. It's wired right across the input wires. It's certainly chunky enough, in theory.

If it is the effect of battery desulphators or something in the charging circuit then, as has already been suggested 'fitting a zener' is not going to make a difference.

I suspect that an inductor or inductors in the input wire is the way to go. iirc desulphators run at a couple of kHz and imposes a hefty ac signal across the battery. there is a lot of energy and what 'could' be happening is that the already fitted zener starts to break down, lets go and the power supply of the units die.

If ..... and it needs to be determined properly first .... it is the effect of the high energy pulses from a desulphator, power zupply, or 'nearby lightning' ( all pretty similar ) then the input protection on the NASA unit needs somewhere to 'dump' the energy when the zener starts to do its job. A fuse is unlikely to be nearly fast enough to blow and anyway you'd just pop the fuse every time the desulphator kicked in. Back to the inductors.

To DC the inductor looks like a piece of wire but when the desulphator AC comes along all sorts of magic happens. My theory is not on the long side but perhaps one of the radio hams on the fora or an approach to NASA could be suggested to select a suitable inductor that will form a cut off filter below say 5 khz. For myself I'm just going to fit a couple of chunky ones I have lying around and make sure the batteries are disconnected from the rest of the boat when and if I desulphate. I am not too happy about sending high energy ac around the rest of the boats equipment anyway. Instruments, radios, vhf, chart plotter all sorts! If the same energy is coming out of your battery charger I would be quite concerned for the other stuff on the boat.

Like others I think NASA provides a good set of equipment down to a price, generally they are very helpful but the chap in charge does not take kindly to any hint of criticism, constructive or not. If you suggest that the input protection of the units is not up to the job that may well be the end of it!
 
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Like others I think NASA provides a good set of equipment down to a price, generally they are very helpful but the chap in charge does not take kindly to any hint of criticism, constructive or not......
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Indeed, I have wind, depth, speed, and AIS by NASA. Apart from an initial problen with the wind instrument (hey, the cups are still on after 3 years!) I've been very happy with them.

It's really puzzled me as to why I've had such trouble with the Supernovas, like I said, I've got other LEDs onboard that have been fine. No other electircal problems that could be put down to a dodgy system.......................
 
I'd be quite cautious about putting inductance in the power lead. I suspect that the supernova has a boost converter to generate the volts needed to drive the LEDs and these can be quite sensitive to the impedance of the power supply.
 
nimbusgb said:
My NASA tricolour conversion. Using only two wires for both lights.

there's a pdf article here
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Excellent, full marks. I'll put it on my list!
What is the wall-thickness of acrylic tube sufficient to machine the lips?
Did you go for the more expensive cast tubing, rather than extruded, for a reason?
Can you suggest a supplier of very short lengths of the cast tubing?
TIA
 
The tube is 90mm * 3mm. It's a bit of a pain to work because the tube distorts when held tightly enough in the lathe chuck. I made a ply disk to fit inside the tube to stop it distorting.

Couldn't find anything shorter than a metre. I could cut you a piece off with a hacksaw and post it. £5 to the lifeboats!
 
galadriel said:
Ah! OK, my tri colour is in good nik, the anchor section is a little crazed, but I guess that matters less.
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Having said this a few days ago. I was cleaning the lamp and the anchor part (crazed) crumbled in my hand! Annoying as it is, better now than at sea.

So now I'm going to have to buy a complete new tri/anchor light, but reading this thread, I think I'm going to spend that bit extra and get the Aqua Signal one, I dont want to be up and down the mast changing NASA ones, warranty or not.
 
Sorry to say that I had a supernova tricolour fitted to my boat in 2011. stepped the mast in April this year and in failed in May. Bad luck I though until I enquired with fellow club members, 2 out of 3 failed within 2 years. I have extolled the virtues of British based NASA marine for many years my first boat was fitted with a Target log and sounder for 25 years no problems and good service. The AIS receiver fitted 2008 great value faultless and very helpful when contacted about set up. As for the Supernova and the masthead wind sensors these products are letting them down. Great shame this is meant to be constructive.
 
Over three years on and about 100 night's use, equivalent to around 800 hours, my NASA LED anchor light continues ok. The only improvement was to use a bungy downhaul so a smart pull on the halliard doesn't separate the glued-on skull from the lamp housing.
 
I had an 'accident' and my Supernova ended up on the sea bed being ground back and forth for three days or so in the sand and gravel. This ruined the lens on one side and moisture had caused a short in one of the red LEDS. I dismantled it and when I completed the circuit round the faulty LED the rest of the LEDs worked fine. I contacted Nasa and they sent me a new lens, seal and top sticker for £5 and threw in a new red LED for me to fit. I soldered the new LED in and sprayed the circuitry with a light covering of grease to prevent further corrosion. It works fine now and my only gripe is the cable length and strand quality which is as bit difficult to handle.

As I don't want to go up the mast I may turn it into a bow bi-colour instead where I have access to it. My electrical system is just a 12v 75 Ah leisure battery fed by a solar panel and controler, so very basic. I hardly use the nav lights so its usually there 'just in case'.

Tim
 
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