Boat Forum / Building / March 2007

They'd die. Google LED.

LED's are restricted as to the amount of current they can stand so a
higher voltage = more current = death. To use with a higher voltage
you will have to (1) use a resister to drop the amperage, or (2)
install a voltage regulator of some sort.

Bruce in Bangkok
(brucepaigeatgmaildotcom)

They don't, it is in fact the opposite. LED's have a very steep U/I curve
just like any diode. They might not draw any current at 1.5V (red LED) and
fry on 2V. LED's operate on current, not voltage. You need to calculate a
series resistor to limit the current to 30mA which is the maximum for normal
LED's.

To do that, take the maximum voltage that you need to apply, i.e. 14.4V for
a 12V system and calculate the resistor as follows:   R = (14.4 - Vled) /
0.03.  Vled depends on the color, red LEDs are 1.6 to 1.8 and yellow and
green LEDs around 2.1V. Blue leds are around 3V but might depend on the
technology used, the same goes for white LEDs.

You should not parallel LEDs and use one resistor since LEDs might vary a
bit in voltage, resulting in uneven currents through the different LEDs. You
can connect them in series, and add the voltages. So 5 red LEDs would need a
total voltage of 5 x 1.6V = 8V. The added benefit is that there is less
voltage drop across the resistor and the overall efficiency increases.

Meindert

There are a number of cool on-line calculators, Google "LED Resistance
Calculator:.

I'm partial to this one:  http://metku.net/index.html?sect=view&n=1&path=mods/ledcalc/index_eng

MW

Maybe you could put 3 of them in a string but it sounds impractical to
me.
They make very bright 12v LEDs but they have a narrow focus, about 30
degrees. Mouser Electronics sells them for $1.60 per. You can get
clusters too for more light.
I have some stick-on LED lights that also run on 3 AAA batteries for
inside cupboards. They seem to last quite a while as long as you
remember to turn them off.
I like the white xenon lights I found at WestMarine for $27 with a
high/low setting which pulls .7 - 1 amp per.
Hurry on spring!