Wiring in a switch to turn a light on and off. Question!

[rexxdoggy]

Okay, so I'm thinking off adding Demon Eyes to the projectors. The LED Im using has 2 wires, power and ground. I want to be able to turn these on and off at will, and only by the switch. How do I go about doing this? Is it as simple as wiring the power and ground from LED to the switch, and wire in a power and ground from the switch to the power source (battery)?

Such as this picture (do I need the fuse in there?)

 

[jrichardson]

you need a fuse to protect the circuit, you don't NEED the fuse but it can cause the LED strip to fail or start a small fire if the system shorts and causes too high of an amperage draw. and yes that is how you wire the lights up, just put the ground on some bare metal and it will be grounded, don't need to go to the battery. and the switch and fuse can be on either the power or ground circuit. I recommend putting them on the ground circuit, you can run the power directly from the battery to the lights and then run the ground into the passenger compartment and ground inside there instead of running two power wires.

 

[rexxdoggy]

Thanks for the input. How big of a fuse will I need to do this? I was looking at fuse holders and looked at 18 gauge. Is that a sufficient?

 

[crewchiefpro]

You need at least a 20 amp fuse, so I would go to 12 gauge. 18 is pretty small size.

 

[rexxdoggy]

Okay. I just figured the wire pigtail is a small gauge so I was gonna try to match it. Ill have to await till they come on still lol :[

 

[dennyb]

Fuses to protect the circuit should be sized relative to the load they are protecting. Example if a circuit draws about 10 amps it would be protected by a 15 amp fuse. This is 150% of normal amp draw (a good rule for fusing circuits) You don't put a 15 or 20 amp fuse onto a strip of LED lights that see less than 1 amp of draw. I would pick the next larger fuse that closely matches a 150% of your lights rated draw.

Note: 18 guage is sufficient for up to 8 amps easily. This chart I found I feel is slightly skewed to higher amps on smaller wires for chassis wiring. The power transmission column is for AC circuits like home wiring and is quite low. Look at extension cords when they have 14 ga used for 15 amp and 12 ga for 20 amp circuits like the wires in your wall.

Chart for wire amp capacity by guage. http://www.cablesandconnectors.com/wiregauge.html

 

[mystiquevltwin]

You could also tie the positive into an accessory wire. This way the key will need to be in accessory position so if you forget to turn the switch off, it will not kill your battery. (I'm assuming that isn't a very good option for you since this is more of a "show" mod, but it is an option). That way, you don't need a wire running directly to your battery.

 

[jrichardson]

I would just use the same size wiring that is on the LED strip pig tail, and the fuse should not be larger then what the wiring can handle, otherwise it does no good for protecting the wiring.