Stebel Magnum fitting questions.

Fuses are there to protect the cable, in this case Suzuki fitted a 15 amp fuse. You will not damage the cable unless you put a larger fuse in the circuit and draw more than 15 amp. You are using no more than the original horn (or very close to this figure) so you are perfectly safe. No additional fuse or relay is required to use the Magnum horn. The switch is also fine for this load.

This burning out of wiring looms by fitting extras is a load of nonsense, unless you are replacing fuses with higher rated ones. The worst you could do is blow a fuse if you overload the circuit.

Switches are also rated to the current they can handle and if you try to switch higher loads than they are rated you may not blow a fuse but could well damage a lower rated switch. This is also where you should use a relay. The relay is just a electro-mechanical switch that takes very little current to operate but can switch loads up to its rating, typically 20-40 amps.

So. Use a relay when you need to supply higher current than the existing circuit is designed to supply.
Use a relay to operate a circuit by a switch rated lower than what you wish to switch.
Use a relay to supply a circuit where you wish to run larger cable to reduce voltdrop.

Single Magnum horn, remove existing horn, replace with Magnum. no other change required. This is what I have done.

If you decide you want to prevent any voltdrop to ensure theoretical maximum from the horn, use a relay and larger cable, in this case don't forget to also use larger earth cable. You can use the existing leads to the horn to operate the relay.
You may do this and find you cannot tell the difference.

Originally Posted by warmshed

Fuses are there to protect the cable, in this case Suzuki fitted a 15 amp fuse. You will not damage the cable unless you put a larger fuse in the circuit and draw more than 15 amp. You are using no more than the original horn (or very close to this figure) so you are perfectly safe. No additional fuse or relay is required to use the Magnum horn. The switch is also fine for this load.

This burning out of wiring looms by fitting extras is a load of nonsense, unless you are replacing fuses with higher rated ones. The worst you could do is blow a fuse if you overload the circuit.

Switches are also rated to the current they can handle and if you try to switch higher loads than they are rated you may not blow a fuse but could well damage a lower rated switch. This is also where you should use a relay. The relay is just a electro-mechanical switch that takes very little current to operate but can switch loads up to its rating, typically 20-40 amps.

So. Use a relay when you need to supply higher current than the existing circuit is designed to supply.
Use a relay to operate a circuit by a switch rated lower than what you wish to switch.
Use a relay to supply a circuit where you wish to run larger cable to reduce voltdrop.

Single Magnum horn, remove existing horn, replace with Magnum. no other change required. This is what I have done.

If you decide you want to prevent any voltdrop to ensure theoretical maximum from the horn, use a relay and larger cable, in this case don't forget to also use larger earth cable. You can use the existing leads to the horn to operate the relay.
You may do this and find you cannot tell the difference.

Thanks Warmshed, was looking for an explanation like this. Very informative. Will stick it on tonight see how i go.

I have a question, fitted the magnum last night and plugged it in first to make sure it all worked OK before taking off the old on etc and it worked perfectly fine and was very loud. However when i fitted it to my bike it sounds all muffled but only when you tighten up the bolt which holds the metal bar onto the OEM bracket. Why is this?? I kinda sounds like a horn with a cold. If you loosen off the bolt (to the point the horn is flapping about) its fine and also fine if you take it off again?

Hi, yes I have noticed that the plastic silver cover seems oversize and when you bolt the horn up, it squashed down. This may be causing your problem. Try putting two or three washers on the horn stud before bolting it up so it does not squash the cover down. Let me know how you get on.

I will look but i dnt think its that stud it seems to be when you fit the bar to the OEM bracket with the std 13mm bolt. will do the washer thing tho.