Air horn compressor current?

[p.dath]

How much current does a "typical" automotive air horn compressor draw?

[pete376403]

The Fiamm horns on my GS1100 draw around 5 amps - enough to warrant running them via a relay rather than letting the wimpy little handlebar switch contacts carry the load. And they are f*ckin LOUD

[p.dath]

The Fiamm horns on my GS1100 draw around 5 amps - enough to warrant running them via a relay rather than letting the wimpy little handlebar switch contacts carry the load. And they are f*ckin LOUD

I have a Fiamm horn fitted to my bike (via a relay), but it has a 20A fuse in it. I was thinking this sounds a bit big, like maybe someone blew a fuse and smacked in what they had lying around.

Might try a 10A fuse (like the majority of fuses on my bike) and see how it goes.

[slofox]

The Stebel Nautilus is reputed to draw "less than 18A"...

[Taz]

All I know is when i use air horns in the falcon the lights dim a little........

[davereid]

The air-horns on my 650 draw 15 amps. Id suggest a 20 amp fuse located as close to the battery terminal as possible, and cable rated for 20 amps minimum. Hang the relay across the terminals designed to toot the original tooter, then your factory loom carries only the current needed to pull the relay in - well under 0.25 amps. Then you are tootin..

[{.bLanK}G_o_D]

Have a look at the compressor. It will (or did) have a plate, tag, sticker with all the relevant information including current draw.
If not, measure it with an ammeter.
If you compressor draws 5A, a 20A fuse is waaaaaaays too big.
But then again, motors have a surge of current on start up, my advise would be to find the model of the compressor so you can find out the manufacturers recommendations.
Or just trial an error.

[p.dath]

Have a look at the compressor. It will (or did) have a plate, tag, sticker with all the relevant information including current draw.
If not, measure it with an ammeter.
If you compressor draws 5A, a 20A fuse is waaaaaaays too big.
But then again, motors have a surge of current on start up, my advise would be to find the model of the compressor so you can find out the manufacturers recommendations.
Or just trial an error.

The plate doesn't have the current draw on it, and my multi-meter (both of them) can only measure current draws up to 10A, and I'm not keen ot fry a meter.

[davereid]

The fuse should be rated as low as possible, but its actually protecting the wiring, not the load. Run cable rated at, at least 20amps, put the fuse as close as you can to the battery and don't worry-guts about the compressors actual load. In the event of a failure the fuse will blow before the cable catches fire... thats why you use 20 amp cable. It IS best practice to use a smaller fuse if you can, but shit, sometimes you cant.

[imdying]

my multi-meter (both of them) can only measure current draws up to 10A, and I'm not keen ot fry a meter.

The A line will be fused, even on a cheapy.

[p.dath]

The A line will be fused, even on a cheapy.

Funnily enough, my cheaper one has "not fused" written next to the 10A terminal.

[CookMySock]

The fuse [is] actually protecting the wiring, not the load. [..] In the event of a failure the fuse will blow before the cable catches fire...

This is a fundamental aspect of wiring that many do not grasp. The fuse size is related to the wiring size, not the current draw from the load.

The fuse is solely there to prevent wiring fires. So the fuse must be a size larger than the load, and critically, the cabling must be a size larger than the fuse.

Steve

[p.dath]

This is a fundamental aspect of wiring that many do not grasp. The fuse size is related to the wiring size, not the current draw from the load.

The fuse is solely there to prevent wiring fires. So the fuse must be a size larger than the load, and critically, the cabling must be a size larger than the fuse.

Steve

I think I might look into this further. Assuming a 12VDC load at 20A (the fuse size), what should the AWG size of the wire be?

[imdying]

Google is awesome.

http://www.powerstream.com/Wire_Size.htm

[CookMySock]

Assuming a 12VDC load at 20A (the fuse size), what should the AWG size of the wire be?

I dunno.

Thick enough to instantly blow the fuse in a fault condition. Buy a box of fuses and test.

Steve