radman
R.I.P. Our Motorcycling Friend
Leave it to FJR riders, when a tech question surfaces, college level engineering courses follow. Don't get me wrong, it's a good thing. I just hope we don't get a proctologist on staff here. 
Magnum Blasters Without Relay
- Thread starter BrunDog
- Start date
Help Support Yamaha FJR Motorcycle Forum:
RonBB
Well-known member
Constant Mesh. Probably more like a pulsing DC current since the current doesn't reverse, but point taken. I hadn't thought that far. The switching would be easier since the zero point is accomplished within the horn. Good point.
panthercity
Well-known member
- Joined
- Jun 25, 2005
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Or we'll have to quit tellin' each other to "stick it!" or "shove it!" then, won't we...Leave it to FJR riders, when a tech question surfaces, college level engineering courses follow. Don't get me wrong, it's a good thing. I just hope we don't get a proctologist on staff here.
:cownoy:
ionbeam
2 FUN
Consult the technical advisor.
One thing's for sure, now we can all make educated mistakes.
Alan
BrunDog
Well-known member
Ionbeam:
Look, I am not trying to piss anyone off, just trying to find the truth and help out others who are interested. Thug, you can blow me - your remark isn't appreciated and I will be sure to treat you likewise in the future.
-BD
I agree, that is my concern. I could only determine the impedance of the switch by taking apart the housing and using a very fine ohmmeter, which I don't have.
I agree, that is my concern. I said it was on the fence. Ultimately I want the system to last AND provide good performance AND not add unnecessary hardware. That is the reason for my analysis (which really is a waste of time for just my application, I am looking to add to this community like others).
Sorry, surface area is not the sole factor in heat dissipation. Thermal conductivity is more important. Glass is, in fact, a thermal insulator (by the same token so is PVC). If you put a heat source in a 1 cubic unit volume of steel and the same one in a 1 cubic unit volume of styrofoam, would they transfer heat equally?
What I would love if someone with a heavy gauge wire set and relay wouldn't mind measuring the voltage across the horns (at their terminals) while they are being activated (use ear plugs). Also measure the voltage across the battery. I did this without the engine running and would appreciate same.
Look, I am not trying to piss anyone off, just trying to find the truth and help out others who are interested. Thug, you can blow me - your remark isn't appreciated and I will be sure to treat you likewise in the future.
-BD
FJRocha
Well-known member
Well... allow me to continue polishing this turd...
(sorry for the long dissertation)
MB Current
I measured the power output of the MB horns, and they can consume up to 7.5A of current (when the output of the horn is plugged). The average current is 4.5A (With free air flow at the output of the horn). These measurements were taking with a 12V car battery using 2 feet of 16AWG wire (bench test setup).
FUSE
On a normal installation, the horns will have free air flow at the output; therefore, the typical current for a standard installation is 9A. The 10A fuse called in the schematic is cutting it too close if you ask me, but since I am not been asked, I won't say it. However, if asked, I would recommend a 12.5A or 15A fuse to allow for cases when the air flow of the horns is impeded (i.e. rain flooding, wasp nests, etc.)
Power on the wire
Given a 14V source, and using the standard wiring; I would expecte to get a voltage drop across the wire of 1.4V to 1.9V. Assuming a worst case of 1.9V; then the power consumed by the wiring would be 1.9V x 9A = 17.1W. Now this is TOTAL power consumed on the entire length of the wiring (positive and negative sides together). I have not measured it, but lets assume that a complete current loop is about 4 feet (worst case is shortest wire), then we end up with a power dissipation of 0.36W per inch (about 4.3W per foot). That is not enough to warm the cable more that a few degrees over a long period of time. One must also take into account the heat dissipation capacity of the cables; but this information is not readily available. Bottom line, the factory cables are 24AWG and will be able to handle the current without a problem. However, you may use thicker wire for bragging points, if nothing else.
Relay needed?
The instant the horn button is pressed; there is an inrush of current flowing through the wires. This current will not be greater that the absolute maximum current drawn by the circuit. However, we are talking about 9A of instantaneous current (assuming an ideal conductor). This inrush of current creates an arc (spark) on the switch contacts. This arc is much greater on the contacts of a relay than on the contacts of a mechanical pushbutton. The reason is that the relay will bounce more than the pushbutton by the action of the spring and the magnetic field. This bouncing will create more arcs per activation, therefore more heat and burning of the contacts. Over a long (very long) period of time, the relay will fail before a pushbutton of equivalent rating for the same application. However, the relay is much cheaper to replace in this particular application. Bottom line; use the relay if you are going to keep the bike for ten or more years.
Other cases
I want to maintain the stock horns for cases where I just want to call attention to a fellow rider, or to signal a cager that I want to move in front of them at a light, or for other situations in which the use of a loud horn is not necessary; But want to also be able to use the blasters by default in case of a left turning moron, or to let the wife know that we really have to go NOW. Using a relay and a toggle switch, I can install the blasters without sacrificing the stock horns.
Other implementation I have in mind is the use of high power transistors (instead of relays) to activate the horns. This will completely eliminate the problem of bouncing contacts and burned relays. I’ll let you know if I end up designing this setup.
Wow, now I need a glass of water...
(sorry for the long dissertation)
MB Current
I measured the power output of the MB horns, and they can consume up to 7.5A of current (when the output of the horn is plugged). The average current is 4.5A (With free air flow at the output of the horn). These measurements were taking with a 12V car battery using 2 feet of 16AWG wire (bench test setup).
FUSE
On a normal installation, the horns will have free air flow at the output; therefore, the typical current for a standard installation is 9A. The 10A fuse called in the schematic is cutting it too close if you ask me, but since I am not been asked, I won't say it. However, if asked, I would recommend a 12.5A or 15A fuse to allow for cases when the air flow of the horns is impeded (i.e. rain flooding, wasp nests, etc.)
Power on the wire
Given a 14V source, and using the standard wiring; I would expecte to get a voltage drop across the wire of 1.4V to 1.9V. Assuming a worst case of 1.9V; then the power consumed by the wiring would be 1.9V x 9A = 17.1W. Now this is TOTAL power consumed on the entire length of the wiring (positive and negative sides together). I have not measured it, but lets assume that a complete current loop is about 4 feet (worst case is shortest wire), then we end up with a power dissipation of 0.36W per inch (about 4.3W per foot). That is not enough to warm the cable more that a few degrees over a long period of time. One must also take into account the heat dissipation capacity of the cables; but this information is not readily available. Bottom line, the factory cables are 24AWG and will be able to handle the current without a problem. However, you may use thicker wire for bragging points, if nothing else.
Relay needed?
The instant the horn button is pressed; there is an inrush of current flowing through the wires. This current will not be greater that the absolute maximum current drawn by the circuit. However, we are talking about 9A of instantaneous current (assuming an ideal conductor). This inrush of current creates an arc (spark) on the switch contacts. This arc is much greater on the contacts of a relay than on the contacts of a mechanical pushbutton. The reason is that the relay will bounce more than the pushbutton by the action of the spring and the magnetic field. This bouncing will create more arcs per activation, therefore more heat and burning of the contacts. Over a long (very long) period of time, the relay will fail before a pushbutton of equivalent rating for the same application. However, the relay is much cheaper to replace in this particular application. Bottom line; use the relay if you are going to keep the bike for ten or more years.
Other cases
I want to maintain the stock horns for cases where I just want to call attention to a fellow rider, or to signal a cager that I want to move in front of them at a light, or for other situations in which the use of a loud horn is not necessary; But want to also be able to use the blasters by default in case of a left turning moron, or to let the wife know that we really have to go NOW. Using a relay and a toggle switch, I can install the blasters without sacrificing the stock horns.
Other implementation I have in mind is the use of high power transistors (instead of relays) to activate the horns. This will completely eliminate the problem of bouncing contacts and burned relays. I’ll let you know if I end up designing this setup.
Wow, now I need a glass of water...
Last edited by a moderator:
radman
R.I.P. Our Motorcycling Friend
Apparently not...
twowheelnut
R.I.P. Our Motorcycling Friend
Priceless. Those comments should be pinned!Leave it to FJR riders, when a tech question surfaces, college level engineering courses follow. Don't get me wrong, it's a good thing. I just hope we don't get a proctologist on staff here.
ionbeam
2 FUN
Posts with content and substance, what a concept -- unlike this is post.
He would starve to death in this forum, some of the people here are perfect a$$ holes :haha:
Toecutter
What would DoG do?
I bought the harness. I think Brun should do what he wants but I don't have any science to support this opinion. I am running Fiamms on the FJR. They were on my Land Cruiser (without a relay) but I swapped them out and put the Magnums on the Cruiser with a relay. The Fiamms seem louder on the bike but it could just be that they're a lot closer to my ears now. I seem to use them more than when they were on the Cruiser. I guess people just notice it better than the bike (duh!). I use them more than I originally thought I would, so I guess they were a good investment. However, they won't actually blow cars out of the way so my handlebars and brake levers are the preferred defensive strategy.
The stock horn wiring is either 18 or 20 awg. It's likely 18 awg. Wiring smaller than 20 awg would be too mechanically flimsy to string throughout the bike.
These 32 volt DC automotive fuses have an inverse time-current characteristic. That is, they'll successfully carry currents much above their ratings for short time intervals with no ill effects.
For instance a 10 amp fuse has the following melting characteristics:
Current, Seconds
170A, 10 mSec
45A, 100 mSec
17A, 1 Sec
13A, 10 Sec
12A, 100 Sec
10A, Days (shouldn't melt)
These 32 volt DC automotive fuses have an inverse time-current characteristic. That is, they'll successfully carry currents much above their ratings for short time intervals with no ill effects.
For instance a 10 amp fuse has the following melting characteristics:
Current, Seconds
170A, 10 mSec
45A, 100 mSec
17A, 1 Sec
13A, 10 Sec
12A, 100 Sec
10A, Days (shouldn't melt)
Last edited by a moderator:
RonBB
Well-known member
From the comments it looks as if at least a few of us are EE's. The discussion reminds me of a comment made about a colleague of mine many years ago. It was said not to ask this individual what time it was because he would explain how the watch worked! I went back & reread this thread. Yep, there are several of us here. No doubt about it. Lots of comments about a very simple circuit. I was just wondering......Do any of you have trouble talking/typing without a sketch pad & pencil like I do?
ionbeam
2 FUN
As a part time job I cure insomnia. All I need to do is start telling someone about my job and they immediately go to sleep. It is a great party trick to speak loudly and do a whole room all at once... :dribble:
Alan
Alan
Last edited by a moderator:
BD....
you have convinced yourself that it is not necessary. So if you are confident in your decisions, then run with it.
You asked for opinions and when you got them, you want to debate it. If you are so certain that you are right, just install them your way. No one cares how you install your horns. I did the WC install and spent about $12 in the supplies to do it. Works perfect everytime. Did I need the heavier wiring and the relay? Damn if I know, but everything posted here so far says that what I did, will most certainly not hurt, fry, burn, melt, or blow anything. So for $12 less, you can take a wait and see approach. If it works forever with no problems, good for you. If not ....... bet you will wonder why you didn't just spend the $12.
However, I am guessing that if something fails, this forum will not hear you say "OK, I will admit now that I was wrong and ya'll were right".
you have convinced yourself that it is not necessary. So if you are confident in your decisions, then run with it.
You asked for opinions and when you got them, you want to debate it. If you are so certain that you are right, just install them your way. No one cares how you install your horns. I did the WC install and spent about $12 in the supplies to do it. Works perfect everytime. Did I need the heavier wiring and the relay? Damn if I know, but everything posted here so far says that what I did, will most certainly not hurt, fry, burn, melt, or blow anything. So for $12 less, you can take a wait and see approach. If it works forever with no problems, good for you. If not ....... bet you will wonder why you didn't just spend the $12.
However, I am guessing that if something fails, this forum will not hear you say "OK, I will admit now that I was wrong and ya'll were right".
Last edited by a moderator:
Warchild
Benevolent Dictator
So what kind of oil does everyone run in the Master Blaster horns.... synthetic, or dino?
:evil:
:evil:
vectervp1
Well-known member
I dunno. We could then get some interesting answers to the "which seat is best" question.Leave it to FJR riders, when a tech question surfaces, college level engineering courses follow. Don't get me wrong, it's a good thing. I just hope we don't get a proctologist on staff here.
FJRandy
Well-known member
OK, it's time to chime back in here.
ionbeam.....as a matter of fact I DID do my own sound test using 14ga. 4" long jumpers to active the blasters through my stock wiring. THEN testing the horns after I installed my harness. I found a 3dB increase at 10' with the harness which comes out to approx twice the volume...so your ear percieves.
I also did a current test on each horn using a (freshly charged) car battery I had lying around as the source. Approx 7 amps for each horn.
brundog.....I am not an electrical engineer or any other engineer for that matter. I install 12v accessories in cars, motorcycles, etc.
I've learned by doing it "hands on" not just from books. I started THAT passion in 1987.
You can do all the "scientific" approach you want, the horns NEED a relay and external power to operate at FULL volume. Period. You will find this out...eventually. But if you feel you can use science to install it correctly, cool for you.
This has been discussed over and over on the "other" boards LONG before I even decided I was going to replace my horns. Nevermind come up with a special harness to make it easy. Selling the harness came ONLY after I was bugged to do it by lots of people at the time. Originally, I had no intentions of mass producing an aftermarket harness. It was just another harness like I make up every day for different auto related things. When I posted a simple question of interest, it took off!
I find it hard to believe that some here are convinced that an 18 or 20 ga wire will do the SAME job of flowing enough instantanious current to operate the horns as a 12 or 14 ga wire. I read somewhere here (I believe) that it was played off as "somewhat overkill" to use a heavy guage wire, and that the "factory" wiring will do just fine. Uuuuh.....it won't. Try it and find out. Your stock horns will sound louder.
So if I sounded somewhat defensive, well....you be the judge.
Anyone can make their own relay setup using Warchild's diagram. That's the bottom line. NO ONE here or anywhere else is having their arm twisted to buy mine. But I guess a few who bought from me just don't have the time/ skills/energy to do it themselves and have decided to buy premade from me. And that's perfectly understandable. And I sure am grateful for all the good feedback and satisfied buyers! I buy LOTS of things I could've made myself, because sometimes the time/effort isn't worth the savings. That's just the way I see it.
It was also posted way back when (on other boards) that a few actually reported "welding" the horn switch contacts by using the Blaster horns with the factory wiring. This discussion alone is what prompted me to come up with an outboard harness (for myself originally!) to eliminate any doubts about the current capacity of the stock wiring and switch.
If I had a dollar for every customer that came in and couldn't figure out why his "cheapo" fog lights keep melting the harness they came with....
That's because the wiring on those off brands is just too small. I'd rewire the whole setup with heavier wire and quality relay and fuse holder and they'd report back now and then with excellent results.
Do yourself a favor and make your own harness. It will save you time and energy in the long run.
I am through having to explain myself, and I'll pass on responding to this thread from here on.
ionbeam.....as a matter of fact I DID do my own sound test using 14ga. 4" long jumpers to active the blasters through my stock wiring. THEN testing the horns after I installed my harness. I found a 3dB increase at 10' with the harness which comes out to approx twice the volume...so your ear percieves.
I also did a current test on each horn using a (freshly charged) car battery I had lying around as the source. Approx 7 amps for each horn.
brundog.....I am not an electrical engineer or any other engineer for that matter. I install 12v accessories in cars, motorcycles, etc.
I've learned by doing it "hands on" not just from books. I started THAT passion in 1987.
You can do all the "scientific" approach you want, the horns NEED a relay and external power to operate at FULL volume. Period. You will find this out...eventually. But if you feel you can use science to install it correctly, cool for you.
This has been discussed over and over on the "other" boards LONG before I even decided I was going to replace my horns. Nevermind come up with a special harness to make it easy. Selling the harness came ONLY after I was bugged to do it by lots of people at the time. Originally, I had no intentions of mass producing an aftermarket harness. It was just another harness like I make up every day for different auto related things. When I posted a simple question of interest, it took off!
I find it hard to believe that some here are convinced that an 18 or 20 ga wire will do the SAME job of flowing enough instantanious current to operate the horns as a 12 or 14 ga wire. I read somewhere here (I believe) that it was played off as "somewhat overkill" to use a heavy guage wire, and that the "factory" wiring will do just fine. Uuuuh.....it won't. Try it and find out. Your stock horns will sound louder.
So if I sounded somewhat defensive, well....you be the judge.
Anyone can make their own relay setup using Warchild's diagram. That's the bottom line. NO ONE here or anywhere else is having their arm twisted to buy mine. But I guess a few who bought from me just don't have the time/ skills/energy to do it themselves and have decided to buy premade from me. And that's perfectly understandable. And I sure am grateful for all the good feedback and satisfied buyers! I buy LOTS of things I could've made myself, because sometimes the time/effort isn't worth the savings. That's just the way I see it.
It was also posted way back when (on other boards) that a few actually reported "welding" the horn switch contacts by using the Blaster horns with the factory wiring. This discussion alone is what prompted me to come up with an outboard harness (for myself originally!) to eliminate any doubts about the current capacity of the stock wiring and switch.
If I had a dollar for every customer that came in and couldn't figure out why his "cheapo" fog lights keep melting the harness they came with....
That's because the wiring on those off brands is just too small. I'd rewire the whole setup with heavier wire and quality relay and fuse holder and they'd report back now and then with excellent results.
Do yourself a favor and make your own harness. It will save you time and energy in the long run.
I am through having to explain myself, and I'll pass on responding to this thread from here on.
Last edited by a moderator:
Bike Effects
Well-known member
Randy, it is people like you, who do these things with thier talent, that make this forum a great place. Thanks for your knowledge and effort.
yamaholic
Well-known member
Dino, naturally. Given the low cost of replacement horns, along with the proven long life of the horns in the absence of oil, I see no reason why synth would be superior in this particular application. :dance:
unk: 
Thug
A shy retiring flower in a Thug's exterior
Hey BD
I did say it with a smiley face ya big baby! look there's another one and another one...grow up
I did say it with a smiley face ya big baby!
look there's another one and another one...grow upSimilar threads
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