Indicator Light Installation

[Sonosailor]

I’m installing a 12 V circuit to run a solenoid on the propane tank from an existing simple panel switch in the galley that has a fuse for each circuit, and smartly am thinking of ways to install an indicator light. I was looking at the Blue Sky LED indicator lights, and wondering how I could use one. Not having a Blue Sky panel that uses these lights, I am ‘in the dark’ on how the wiring is done. I presume I need a resistor of some size which is wired in parallel with the circuit to the solenoid? Should I give up and find a small red incandescent indicator that I can wire in series and put somewhere?

[dougweibel]

No need to go with an incandescent. LED's need to be wired with the correct polarity and with a current limiting resistor but that is easy enough. If you get the polarity backwards it generally will not harm the LED, it just won't light.

The BlueSea Indicator LEDs appear to have a resistor built in, so you don't need to worry about picking the right size resistor. Just wire the polarity correctly and you will be good to go.

[jamhass]

There are many cheap 12 volt Led indicators that will work fine if out of the weather. Try autozone etc.
If needing weatherproof then maybe the marine focused outlets.

[HeywoodJ]

If you can figure out the make/size of the current switch my preference would be to replace the switch with a version that has a built-in indicator light. Cleaner and easier to my mind, YMMV.

If not, put the light in parallel, then no special circuitry required, any 12V light/LED that fits and strikes your fancy can be installed.

[Spot]

Originally Posted by Sonosailor

I’m installing a 12 V circuit to run a solenoid on the propane tank from an existing simple panel switch in the galley that has a fuse for each circuit, and smartly am thinking of ways to install an indicator light. I was looking at the Blue Sky LED indicator lights, and wondering how I could use one. Not having a Blue Sky panel that uses these lights, I am ‘in the dark’ on how the wiring is done. I presume I need a resistor of some size which is wired in parallel with the circuit to the solenoid? Should I give up and find a small red incandescent indicator that I can wire in series and put somewhere?

They make 12vdc switches with built-in indicator LED's as mentioned above...no resistors needed...instructions come with the switches. Indicator lights make more sense to me wired in parallel so a bulb does not affect or disable the rest of a circuit.

[Sonosailor]

Well, I’ve gone through two Blue Sea red LEDs. I threw the first one away thinking I must had reversed polarity, and the first one worked when I held it in place. I soldered it similarly, and no light. Oh well, our memory for the switch is working. I do like that switch provided by Spot. If I see it, I’ll buy it.

[Bycrick]

When I bought this new boat, it too had an incandescent bulb indicator wired in parallel with the propane solenoid. Worked for a while, then quit lighting. Haha, said I, I’ll put in an LED and it will last forever. Three LEDs later, I finally realized that when you turned off the solenoid, it produced a voltage surge that quickly took out the LED. Once I put a snubber diode across the LED, the problem went away.

[Sonosailor]

Sorted this problem by going from switch to light to another ground.