I'm going to be hooking up 3 LED's to my electronic exhaust cutout switch panel. They are rated at 12 volts. They will be on most of the time....when the cutout is opening...they are off, when the cut out is completely open or completely closed, they will be on. Will I need to add resistors to these? Any help would be appreciated. Thanks alot

Shawn-

 

If they are rated for only 12V then you will need to use a resistor as the charging system will be putting out something on the order of 14.5 - 14.7 Volts.
Here's a calculator to help figure out what value and power rating you'll need http://www.hioutput.com/tech/circuits/resistance.html
Unless the mA rating of the LED is listed higher, use 20 in that box.

 

man, this electrical stuff isn't making much sense to me at all. Is there anyway you could help me out? Here are the specs of the LED's I bought: -12VDC 20mA 1.5mcd With inegrated resistor-

I'm going to be hooking 3 of the LED's up....

Am I going to need 3 resistors? What do I ask for? What do I get?

 

It looks like you'll need some 150 ohm resistors which you can get from Radio Shack PN 271-1109, cost: 5 for 99¢.
I'd use one for each LED; you can solder them to either lead. The LED will light up only when power flows through in one direction, so just make sure they light up when you want them to before permanently mounting them.

 

alright man, thanks alot...I'll pick a pack of those up this week! I'll let you know how it goes when I get ready to do this. Thanks again