Horn relay
- Thread starter jarama79
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Dellortoman
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- Location
- Tasmania, Australia
It's not clear from Cape's diagram, so just to clarify ...
The fused feed from the battery to pin 30 is the one that's carrying the horn current (maybe 10 Amps), so it needs to be sized appropriately, as does the fuse. Pins 85 and 86 only carry the signal current that switces the relay (a fraction of an Amp), so can be lighter gauge wire.
The old feed wire to the horn that Cape shows as powering the relay solenoid via pin 86 is big enough to also carry the horn current (that's what it was doing before you put the relay in the circuit). So you can save on wiring by using that old horn feed to provide power to pins 86 and pin 30, eliminating the necessity for a separate fused feed from the bttery to pin 30.
The fused feed from the battery to pin 30 is the one that's carrying the horn current (maybe 10 Amps), so it needs to be sized appropriately, as does the fuse. Pins 85 and 86 only carry the signal current that switces the relay (a fraction of an Amp), so can be lighter gauge wire.
The old feed wire to the horn that Cape shows as powering the relay solenoid via pin 86 is big enough to also carry the horn current (that's what it was doing before you put the relay in the circuit). So you can save on wiring by using that old horn feed to provide power to pins 86 and pin 30, eliminating the necessity for a separate fused feed from the bttery to pin 30.
Dellortoman said:
Not a good idea. First we need to ask what we are trying to accomplish with this relay mod. Well, it's actually quite obvious, more power to the horns and thus louder sound. And the way to do that, is to get the power directly from the battery (via fuse). Getting the power to pin 30 from old horn feed would make the whole mod pointless. The wiring goes all over the harness (at least on triples) and adding a relay to this would not increase the power. To make it clear, relay itself doesn't increase power, it is used only to control the power feed. There's no power consumption if the setup is on idle, but when you press the horn button, 86-85 grounds and the relay activates 30-87, allowing power to the horns. Getting power to pin 86 can come from anywhere, but since the old power feed is removed from the horns, why not to use it. I hope this helped to clear things.
Dellortoman
Hero member
- Location
- Tasmania, Australia
cape said:
Not necessarily. Voxbell horns in good condition are generally quite loud. If you want to make more noise, get better horns.
The object of the exercise (in my mind anyway) is to reduce the current through the crappy little horn button switch, and to eliminate the resistance of this switch from the horn feed. The button switch is the weak link in the system. As with the starter button switch, its little innards are at risk of overheating with frequent or prolonged use of the horn. A fried switch will stop the horns working at all.
The old horn wire is OK to feed power to the horns if all the connections are good. If the wiring harness is in such a state that the existing horn feed is inadequte, then you might need to consider a re-wire.
Just wanted to say thank you for all the advice,drawings etc. Now feeling much more confident around a relay. Quite brings a tear to my jaundiced old eye that there are folk who have the patience to delay with electrical cretins like myself. Thank you all again. Regards Stuart
Dellortoman
Hero member
- Location
- Tasmania, Australia
cape said:
Me too. Only times I've ever needed to use the horns on a motorcycle have been to demonstrate their operation to a roadworthy inspector. They're pretty useless things really.
This raises the obvious question, what is the purpose of a horn?
If you toot the horn at another driver, you're doing one of several things: saying hello to a friend, expressing your displeasure at something they've done, or alerting them to a hazardous situation. The first two are nothing more than social interaction, so aren't relevant to road safety. The latter comes with a presumption that the other driver will hear your toot, immediately recognise and understand the problem, then react (correctly) to mitigate the hazardous situation - a bit of a long shot really.
Rather than honking a horn in the hope that the other driver will sort out whatever the problem is, you'd be better off using whatever time is available to take evasive action yourself.
Dellortoman said:
But because we are all sharp-witted, quck-thinking super heroes, we're able to take evasive action and honk the horn at the twat that's just about to t-bone us at the same time to give us the extra split second that the twat realises the situation he has created (provided it's his fault in the first place...)!
Don't need or use them often, but wouldn't want to miss them. They have turned quite a few certain scathes into near-misses for me. Must be a reason why every vehicle is still fitted with them.
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Reggie3cl
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Fitted a ferociously loud Stiebel horn to my GS - hitting it in a confined space like my wee shed is horrible- and used it many times recently as a warning that I am near to people/donkeys/goats etc, genuinely needed as the bike doesn't make much noise at all. Kids in particular jump out of their skins.
Have to sort out the one on the RGS, for some reason it only sounds a muted note, even though it is the original (pretty good one) one off the BMW. A loud horn is vital IMHO on today's roads- has to penetrate the heads of VIPs (virgins in Peugeots).
Have to sort out the one on the RGS, for some reason it only sounds a muted note, even though it is the original (pretty good one) one off the BMW. A loud horn is vital IMHO on today's roads- has to penetrate the heads of VIPs (virgins in Peugeots).