Horn on a riding mower?

[Carscw]

A relay is kinda like a solenoid if you do not use a relay you will need to use thick wire and I am thinking a 30 amp fuse if you use a relay you only need about a 15 amp fuse.

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[Grass ala Mowed]

The relay does not replace the fuse or reduce the load. Properly wired, the fuse will blow to protect the circuit from a short circuit. If the horn draws 15 amps (and I think that's high) you need a 20 amp fuse. The fuse should be in the power wire (use an in-line fuse holder) before the relay. I have seen unfused circuits cause vehicle fires and a lawn mower battery has enough power to start a fire.

 

[JoeNoble]

The relay does not replace the fuse or reduce the load. Properly wired, the fuse will blow to protect the circuit from a short circuit. If the horn draws 15 amps (and I think that's high) you need a 20 amp fuse. The fuse should be in the power wire (use an in-line fuse holder) before the relay. I have seen unfused circuits cause vehicle fires and a lawn mower battery has enough power to start a fire.

I won't wire anything without a fuse.... EVER! I'm just trying to figure out if the relay is actually necessary or not. But what your saying is that it should require the same fuse with or without a relay?

 

[Grass ala Mowed]

Since the relay requires a small amount of power to operate, it will increase the draw slightly, on the order of 1/4-1/2 amp. The relay allows use of smaller wiring to the horn button and a smaller button. But look at the horn rating and the button rating, we may be making much ado about nothing.

 

[reynoldston]

Since the relay requires a small amount of power to operate, it will increase the draw slightly, on the order of 1/4-1/2 amp. The relay allows use of smaller wiring to the horn button and a smaller button. But look at the horn rating and the button rating, we may be making much ado about nothing.

Like said before the most its going to do is burn up the points in the horn button without the relay. If that happens would be the time to add the relay if you want to try it without. The relay can't be that expensive and what little bit more wireing why would you not want to use a relay and be done with it. Relay or not I would still use a 20A fuse.

 

[JoeNoble]

Yeah may as well just use the relay I suppose but theoretically wouldn't it blow the fuse rather than burn up the switch? I'll probably wire it up tonight and let you guys know what happens.

 

[Grass ala Mowed]

If the fuse is rated higher than the switch, technically a no-no, the switch could burn out without blowing the fuse. In household wiring codes, admittedly not really applicable here, the wiring, switches, and outlets must all be rated the same or higher than the fuse or circuit breaker. The fuse or circuit breaker are to protect the wiring and prevent fires from overheated wiring.

 

[hankthecrank]

Grab a battery charger connect the charger to the horn temporarily and read the charge rate that will tell you pretty close what the amp pull is going to be. The horn may even be stamped with that kind of data. Just use the relay it will shorten up the power circuit to the horn and yoiu will not need the heavier gauge wire to the horn switch.

 

[JoeNoble]

Didn't get to do any wiring but here are some pics of mounting ideas.

Horn button

Here are pics of two horns mounted though I'll probably only use one.

 

[crazyoldtractor]

You could do the relay,that would probably be a better way to do it, or you could be simple and just have the horn direct to the battery with a push switch. Don't worry about battery issues, you'll be fine. Doesn't draw much power.