Boat project question

Hi I help on a boat and we have decided to replace the internal lights with LED's
They will be red for the navigator and white else where.
I have been thinking of using 10mm ultra brights spec:
http://www.component-shop.co.uk/html/rl81u.html

however i have a few questions:
1) resistors. To get 12V I will need to wire 4 led's in series. This should then be protected by a resistor as the voltage can go as high as 15V. Should each LED have its own resistor or one for each chain.
2) placement. To a certain degree this is going to be trial an error. We have been thinking that we would create led strips by mounting them in wood and sticking the wood to parts of the boat. Ideally we would like a nice even lighting throughout the boat with spots on areas like the table.

mountainpenguin said:

Hi I help on a boat and we have decided to replace the internal lights with LED's
They will be red for the navigator and white else where.
I have been thinking of using 10mm ultra brights spec:
http://www.component-shop.co.uk/html/rl81u.html

however i have a few questions:
1) resistors. To get 12V I will need to wire 4 led's in series. This should then be protected by a resistor as the voltage can go as high as 15V. Should each LED have its own resistor or one for each chain.

Click to expand...

Depends on whether the LEDs are different from one another, and also on personal preference, to some degree. Also, it's not the voltage you need be concerned about, so much as the current through the LED junctions (forward current). Google for "led calculator" and play around with some of those. That will give you a good idea of possible architectures.

mountainpenguin said:

2) placement. To a certain degree this is going to be trial an error. We have been thinking that we would create led strips by mounting them in wood and sticking the wood to parts of the boat. Ideally we would like a nice even lighting throughout the boat with spots on areas like the table.

Click to expand...

I think you're on your own, there, although I should think that under the gunwales would be a good spot...

You should also have voltage spike protection. Transients on a 12 volt car or boat system can be extremely high and damaging to LEDs. I'm no expert on that, but perhaps a 15v zener diode across the supply to the LEDs would do the trick.

err, i was boating a few yrs back ......

anyway, usually will draw current from backup SLA charged by yr main engine.
therefore is a 12V, else there maybe having an alternator somewhere ...., check with a multimeter to see yr boat is actually on 12V or 24V ??

i believe using 'sealed' LEDs is an advantage due to its a boat .....

try those MR16-leds, and leds sealed strips

Try to see from here :www.theledlight.com/dcbulbs.html
and here too : www.theledlight.com/waterproof-strips.html

it will be good if u change yr navigation lights to LEDs also.

some extra which u may use if available which is having a 12V primary batteries (alkaline = 8 x D cells, in a sealed waterproof container ) with a connector out to use as a backup supply of power incase things go wrong, as a boater, nothing is prefect when out there ...

Oh those 10 mm u said, its spot at 10 degree btw .... u will prefer flood ones ....

will be glad if i can help u more, by not confusing u further

nope not confused so far. I should have added when i said boat i meant a yacht the lights are for the main cabin. No water in there if there is non working lights are the least of the worries .
We will be changing the nav lights as well in time but wanted to experiment in a less "risky" area first.
Am i right in thinking that a 10 degree spot would be ~17cm wide at 1m throw?
I will ask the owner about voltage spikes but I dont think it ever has them apart from going upto 15v as it is charged from.
So i guess i am going to have to look for a less spotty cheap led.
The main reason i had chosen the linked ones was they were cheap and the sop is at the end of my road.

I have purchased quite a few LEDs from these folks:
http://www.superbrightleds.com/
including their "headlight accents," which are really just LEDs with pre-wired current-limiting resistors, ready for 13.8VDC. Prompt, and decent quality.

They also have multiple-LED light bars and such...

12 volt systems charged with alternators typically have rather dirty power. When a load comes off line, it takes a bit for the regulator to react, and in that brief interval you can have a very high voltage spike. Don't ignore the potential problem just because you don't know about it.


On the other hand, if it is easy and cheap enough to replace LEDs that have gone bad, you might just take the chance and see how they do.

This is a very interesting project -- a boat is a perfect application for LED lighting. Great idea!

First of all you probably want a separate resistor for each Led and I would wire them in parallel with the power source, not in series. If they are wired in series and one led "goes out", for whatever reason, the others will shut down too. If they are wired in parallel, this wont happen.

And your Boats Power, like a cars, is going to fluctuate. It isnt going to stay at a constant 12 volts (your car has a 12 volt battery yet the voltage may get as high as 15+ volts at times). So you might try using a 5 Volt Regulator in a T03 case, heat sunk, which would be powered from the 12 volts. This will give you a regulated constant voltage and will provide "short circuit current limiting" should a short circuit occur. You will still need one resistor per Led. You should be able to get the regulator and an appropriate heat sink from any Radio Shack. You may even need more than one regulator depending on how many and what type of Led you use.

hmmm but i bear different in some views here, welll ....

Due to the nature of the project, its a boat, therefore, power source do comes from the backup SLA and the engine alternator ......

how abt getting a Led Driver such as BuckPuck or similar :
www.leddynamics.com/LuxDrive/drivers.php

as the driver will 'welcome' any increase of voltage but will 'maintain' the same output of voltage and current ..... yea

as the 10mm is spot, its quite .... 'bright' to 'stare' at it for normal people.
there are versions of 5mm wide angle, anyway, u can always buy a few each first and try which one really suits u, then rest is some leds project.

u nvr really know till u hands on, right?

as leds do give out some form of light at the side, u got to space them out jus enough "not" to waste any ...... but close enough to form an array of light.

however, yr idea is not young as there has been reports that new boats now do comes with LEDs instead of old halgoen ones ..... no need to change light bulbs and bulb comes in "plastic lens" instead of fraglie sharp glasses and some form of waterproofing is like a small wonder to boat-owners and sailors alike.

lastly, some people may like the idea of having "warm" white leds as compare to white white leds.

will get back to u again once u absorbe ....

cheers

roadie said:

[...]lastly, some people may like the idea of having "warm" white leds as compare to white white leds.[...]

Click to expand...

Truely. I'm considering these for under-the-cabinet use...
"Warm White (3300K) - 20 Lumen Output - 140°"

http://www.superbrightleds.com/fit.htm

Regarding use of red LEDs in the navigation room... do any of your navigation tools use red colors? (i.e. Maps with red lines, a sextant with red indicators, or whatever.) If so, you won't be able to see them under red light... might want to add blue and green LEDs to the mix.