This is why you need a relay

[nickyg]

A friend said his lights mounted on his bull bar stopped working (Nissan Titan) and he smelt burning. some field maintenance/parking lot repair revealed this.
Apparently it's just straight wired to the switch. .http://tapatalk.imageshack.com/v2/15/02/06/bbdf2d060c578da080af235f0e1d131c.jpghttp://tapatalk.imageshack.com/v2/15/02/06/61cc0090fb9478fbdc8b5563b3e704f8.jpg



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[slvmart]

Pop Tart ! 00 Wires and some beefy connectors should take care of that ! Who needs a stinking relay !

[Mudderoy]

amp = watt / volt

4.6 amps = 55 watts / 12 volts (that would be one light)
8.3 amps = 100 watts /12 volts (one 100w light)

I wouldn't want 5 amps over my leg much less 17.

[NeverSmashaPaul]

:banghead:
I always preach relays to my friends. A lot of them don't listen till something like that happens.

[Carves]

Thought my car was going to burn to the ground one night in a carpark ... due to a no relay, home brew, bodged airhorn fitting.

... but me and another bloke used our extinguishers to put out the flames,




... coming from the car parked next to us .. :rolleyes:

[Mudderoy]

http://www.nasa.gov/sites/default/files/circuit-xltn.jpg

http://www.xtremelandy.co.uk/Manuals%20folder/Equipment/Simple%20Relay%20Wiring%20Diagram%20(JPEG).jpg

[XJ Wheeler]

Now, I've come a long way in learning electrical but i'm not sure if i'm not getting something here so always better to make sure. On a harness running say 9 amps like your typical set of 55w lights isn't just having an inline fuse adequate? Seems running a relay on something pulling so little would be a waste of wire and more to route.

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[autotech98]

Another question if you are running led lightscwith much lower draw is it still necessary?

[Mudderoy]

I like as much as the current to stay out of the cab. Relays are cheap, and easy to use. It also means you can use small low current wire for switching, important if you're going to have several switches. Put all the stuff that is more likely to catch on fire, on the side of the firewall that you are NOT on.

[4.3LXJ]

Now, I've come a long way in learning electrical but i'm not sure if i'm not getting something here so always better to make sure. On a harness running say 9 amps like your typical set of 55w lights isn't just having an inline fuse adequate? Seems running a relay on something pulling so little would be a waste of wire and more to route.

Sent via messenger pigeon - i talk, he types.

If you are only running 9 amps, an in line fuse is fine. But 9 amps is too close to 10 amps, so you would need to run a 15amp fuse


Another question if you are running led lights with much lower draw is it still necessary?

It still depends on total draw. A good Carling switch is rated at 20 amps. So if we apply the 75% rule to it, you should not put more than 15 amps constant load through it. If you were to exceed that, then a relay would be needed

[autotech98]

Thanks steve.time to get some relays

[nickyg]

I never thought or knew too much about relays till I stumbled across this forum.
When I put some lights on my jeep I went with the matt from bleepinjeep relay box mod. It was really easy and looks really nice. AND....... If I can do it anyone can.

[autotech98]

That sounds like a good idea...then they are mounted securly.

[XJ Wheeler]

If you are only running 9 amps, an in line fuse is fine. But 9 amps is too close to 10 amps, so you would need to run a 15amp fuse



Oh yeah, i run a 15 and fuse and 25 amp switch. Just making sure.



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