GL1000 factory service manual, rectifier positive wire IS connected between the battery and main fuse, many others are done the same. Rotor, stator, reg/rec, same type of charging systems.
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Positive Rectifier To Battery Wire, Fused Or Not?
- Thread starter mrtwowheel
- Start date
Bob Kelly III
Ranch Kid from way back,.... that got Old !
xjwmx: Northern cal. near the oregon border sitting beside Mt.shasta is where I'm at
drop on by and I'll make a pot of coffee for ya !
163 California st. easy to find by the grave yard ! just off the road to Klamath falls, OR.
Bob.........
drop on by and I'll make a pot of coffee for ya !
163 California st. easy to find by the grave yard ! just off the road to Klamath falls, OR.
Bob.........
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Bob Kelly III
Ranch Kid from way back,.... that got Old !
Mrtwowheels: I did read the entire thread, seams you need to take a break ! and I think you do need help because you don't seam to understand, but if you don't need help no problem ! see ya !
Bob.........
Bob.........
Yes I understand Bob, heat and current are the same thing, why else would the wire get hot? I'm saying that the fuse would blow even if the red wire was connected between the battery and the fuse. These guys have the assumption that the current will go only one way depending on where the fuse is.
Interesting point raised by mrtwowheel. I have done a little search and the 75-77 GL1000 wiring diagram shows no fuse between the rectifier +ve and the battery:
75-77 GL100
http://www.wiringdiagrams21.com/wp-content/uploads/2008/07/honda-GL1000-wiring-diagram.jpg
Move on a few years to the GL1100 and the fuse situation is now as per the diagrams and advice offered in this thread:
80-82 GL1100
http://goldwingdocs.com/forum/viewtopic.php?t=27384
So why did Honda make the change? I do not know but wonder if they originally considered the diodes in the rectifier to be sufficiently reliable to make fusing unnecessary. But it is all fine to assume and wonder about what may have been....
I personally go for the fuse positioned as advised in this thread, not because I am a brown nose, but because the auto-electrical books I have referenced in the past state that the rectifier output to the battery should go via a fuse.
Regarding mrtwowheels decision, I suggest reviewing the wiring diagrams of more recent motorcycles and see what the current best practice is. I know it is difficult when a top brand does something that appears at odds to what others are advising.
Best of luck.
75-77 GL100
http://www.wiringdiagrams21.com/wp-content/uploads/2008/07/honda-GL1000-wiring-diagram.jpg
Move on a few years to the GL1100 and the fuse situation is now as per the diagrams and advice offered in this thread:
80-82 GL1100
http://goldwingdocs.com/forum/viewtopic.php?t=27384
So why did Honda make the change? I do not know but wonder if they originally considered the diodes in the rectifier to be sufficiently reliable to make fusing unnecessary. But it is all fine to assume and wonder about what may have been....
I personally go for the fuse positioned as advised in this thread, not because I am a brown nose, but because the auto-electrical books I have referenced in the past state that the rectifier output to the battery should go via a fuse.
Regarding mrtwowheels decision, I suggest reviewing the wiring diagrams of more recent motorcycles and see what the current best practice is. I know it is difficult when a top brand does something that appears at odds to what others are advising.
Best of luck.
I have been looking up wiring diagrams from Honda bikes made in the 70s and 80s. I have found models both with and without a fuse between the rectifier and battery. Here are some:
Without Fuse: GL1000, CD125, CB175 CB350 CX500
With Fuse: CMX250, CG125, XL80S
Edit: Africa Twin 650 and the 2012 CBR1000RR both are fused.
Wow!!!
Without Fuse: GL1000, CD125, CB175 CB350 CX500
With Fuse: CMX250, CG125, XL80S
Edit: Africa Twin 650 and the 2012 CBR1000RR both are fused.
Wow!!!
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Bob Kelly III
Ranch Kid from way back,.... that got Old !
Back to the original question positive to the rectifier fused or not ???? Fuse it...why not ? what is it going to hurt ?
a bit of doubling up on safety features never hurts a thing !
....as far as what Honda did is pure stupidity just like their earlier dumb moves on the Honda 90 I burned out 4 selenium rectifiers on that darn bike in the years I owned it.... and when they went out it tried to burn up the wiring harness ! so it looks like Honda went back to it's old ways to save a few cents..... the last time I replaced the rectifier I added a fuse in line and it never again tried to melt the wiring harness
..... lets face it , ALL motorcycle manufacturers including yamaha do stupid things to pinch pennies, look at the oil sump on the XS650
that is a perfect example of penny pinching that was utterly stupid ! use a heavier screen for gods sake ! it's not that hard to figure out !
but they didn't because it cost MONEY......
so add a fuse..... add 2 or 3 lord knows more couldn't possibly hurt ! LOL
Mrtwowheels : I think you are misunderstanding what they are saying , not that they think the current will only go one way ... they know very well that the current will take the shortest path to ground possible , it is how it is hooked up that is so confusing
if it were me and I was worried about it I would add another fuse on the red wire..... simple and easy fix and no more worries
.....( i think you guys are saying the same thing , just your saying it differently and it's getting confused ! )
Bob.......
a bit of doubling up on safety features never hurts a thing !
....as far as what Honda did is pure stupidity just like their earlier dumb moves on the Honda 90 I burned out 4 selenium rectifiers on that darn bike in the years I owned it.... and when they went out it tried to burn up the wiring harness ! so it looks like Honda went back to it's old ways to save a few cents..... the last time I replaced the rectifier I added a fuse in line and it never again tried to melt the wiring harness
..... lets face it , ALL motorcycle manufacturers including yamaha do stupid things to pinch pennies, look at the oil sump on the XS650
that is a perfect example of penny pinching that was utterly stupid ! use a heavier screen for gods sake ! it's not that hard to figure out !
but they didn't because it cost MONEY......
so add a fuse..... add 2 or 3 lord knows more couldn't possibly hurt ! LOL
Mrtwowheels : I think you are misunderstanding what they are saying , not that they think the current will only go one way ... they know very well that the current will take the shortest path to ground possible , it is how it is hooked up that is so confusing
if it were me and I was worried about it I would add another fuse on the red wire..... simple and easy fix and no more worries
.....( i think you guys are saying the same thing , just your saying it differently and it's getting confused ! )
Bob.......
Paul, that is a Clymer diagram for the GL1000, but the owners manuals and the "factory service" manuals for the GL1000's have the same wiring in that area.
I'm not really sure if I've ever heard of a bad rectifier or other charging problems blowing the main fuse. I've fixed charging problems on a number of bikes and never had blown fuses associated with them.
Scott
I'm not really sure if I've ever heard of a bad rectifier or other charging problems blowing the main fuse. I've fixed charging problems on a number of bikes and never had blown fuses associated with them.
Scott
mrtwowheel, everywhere I look the GL1000 shows direct wiring to the battery. I have tried searching about any rectifier problems relating to a fuse not being used on the GL1000 but have so far found none. Also I did not realize just how far back PMA systems went until today.
I think the XS way of wiring the rectifier output via the fuse is technically a full proof design. But is it absolutely essential based on Honda's past history and experience? Certainly it would deal with a short to ground in the line to the rectifier, but just how likely is that event????? You know my bias on the subject.
Have fun whichever way you decide - Paul.
I think the XS way of wiring the rectifier output via the fuse is technically a full proof design. But is it absolutely essential based on Honda's past history and experience? Certainly it would deal with a short to ground in the line to the rectifier, but just how likely is that event????? You know my bias on the subject.
Have fun whichever way you decide - Paul.
Yeah, I've got nothing against doing it either way. Just so interesting, is anything really protected either way, is the question to ponder. I would think that it would be better to protect the harness and all that is connected to it instead of just the battery etc.
Scott
Scott
I hope the following is helpful, I am off work ill today so are a little bored.
The battery does not really need to be protected except from going flat and the regulator takes care of this. As pointed out earlier the battery is capable of pushing out a very high current. Therefore the harness with its thin wires needs to be protected from the battery.
The harness is primarily protected from these high currents by the 20A fuse. 20+ Amps can damage the harness but the main red wire to the ignition switch will tolerate this for a short time as it has a higher current rating. Hopefully this red wire survives long enough for the 20A fuse to blow.
On later model XS bikes the harness is further subdivided into three main zones, each of which is protected by a 10A fuse. So the harness is quite well protected. If a very high current enters the harness this will not damage any attached devices because they can only draw a current as defined by their resistance (We are not talking about voltage surges). So where does this high current go, or more interesting, how is it produced?
The high current will have been the result of a low resistant path to the frame i.e. a short circuit. If this short circuit were in the lighting section of the harness then the 10A fuse would blow. When the 10A fuse blows the short circuit is now isolated from the battery so the high current immediately ceases to flow and the 20A fuse does not normally blow.
If the red wire is shorted between the 20A fuse and the ignition switch then a high current will flow. The red wire will tolerate a high current long enough for the 20A fuse to blow. At this time the short is now isolated from the battery and the battery just sits there doing nothing and the harness is safe from further damage.
There is a problem with my SH's harness. The taillights are wired directly from the 20A fuse as shown in the diagram of Entry 3 by gggGary. The wiring is not suitable for high currents so it is possible that if it is shorted the wiring insulation may melt before the 20A fuse blows; Note - A short circuit may have a slight resistance resulting in close to 20A being drawn and this may not be sufficient for the 20A fuse to blow quick enough but just high enough to burn out a lighter wire and damage those bundled next to it in the harness.
In summary a high current capable of damaging the harness will be the result of a short circuit. The harness is protected by the use of fuses. The rectifier wiring shares the harness so putting a fuse between the rectifier and the battery just prevents the possibility of severe wiring damage should a short in that section of wiring occur.
The battery does not really need to be protected except from going flat and the regulator takes care of this. As pointed out earlier the battery is capable of pushing out a very high current. Therefore the harness with its thin wires needs to be protected from the battery.
The harness is primarily protected from these high currents by the 20A fuse. 20+ Amps can damage the harness but the main red wire to the ignition switch will tolerate this for a short time as it has a higher current rating. Hopefully this red wire survives long enough for the 20A fuse to blow.
On later model XS bikes the harness is further subdivided into three main zones, each of which is protected by a 10A fuse. So the harness is quite well protected. If a very high current enters the harness this will not damage any attached devices because they can only draw a current as defined by their resistance (We are not talking about voltage surges). So where does this high current go, or more interesting, how is it produced?
The high current will have been the result of a low resistant path to the frame i.e. a short circuit. If this short circuit were in the lighting section of the harness then the 10A fuse would blow. When the 10A fuse blows the short circuit is now isolated from the battery so the high current immediately ceases to flow and the 20A fuse does not normally blow.
If the red wire is shorted between the 20A fuse and the ignition switch then a high current will flow. The red wire will tolerate a high current long enough for the 20A fuse to blow. At this time the short is now isolated from the battery and the battery just sits there doing nothing and the harness is safe from further damage.
There is a problem with my SH's harness. The taillights are wired directly from the 20A fuse as shown in the diagram of Entry 3 by gggGary. The wiring is not suitable for high currents so it is possible that if it is shorted the wiring insulation may melt before the 20A fuse blows; Note - A short circuit may have a slight resistance resulting in close to 20A being drawn and this may not be sufficient for the 20A fuse to blow quick enough but just high enough to burn out a lighter wire and damage those bundled next to it in the harness.
In summary a high current capable of damaging the harness will be the result of a short circuit. The harness is protected by the use of fuses. The rectifier wiring shares the harness so putting a fuse between the rectifier and the battery just prevents the possibility of severe wiring damage should a short in that section of wiring occur.
If you didn't have fuses in your house, when something happened to your wife's iron, say its heating coil broke so that instead of having some resistance it became a short, there's a chance the wiring inside the wall would heat up or burn in two and spark and cause a house fire. The purpose of the fuse is to safely burn in two and cut off the power before anything can happen to the wiring. Current through something causes it to heat, and the more current the more heat. The lower the resistance, the more current. A short, 0 resistance, is maximum current. Thick wire can handle more current than thin wire, so the thin wire fuse burns in two and saves the house wiring. You'd want the fuse as far back as possible so that it would catch everything -- not leave some outlets unprotected. Modern houses use circuit breakers instead of fuses, but same difference.
If you throw a short across the battery, something bad will happen to the battery. If batteries never exploded and were free I'd agree the battery doesn't need to be protected from that. The fuses on these is actually protecting the battery too...
xjwmx, very good point about protecting the battery!
No, the fuse(s) on a motorcycle/car/truck, do not protect the battery. If you drop a wrench across the 2 battery terminals in a bike/car /truck, there will be arcing and the wrench will likely melt or the battery may explode. Its the same for the large cable that runs down to the starter motor. If that cables copper wire touches ground while the push button is pushed, a huge current flow will occur and the cable may melt and cause a fire.
That is why all small wiring must have a fuse or circuit breaker as the first thing in line as the power flows from the battery terminal.
Something you all need to understand. The motorcycle manufacturers building bikes in the 1960s, and into 1990s designed their wiring as they thought was correct at that time. Yes it appears that some of them did not fuse the wiring that comes from the rectifier. Was that the safest way to wire the bike........................no it was not. Any bike wired that way, is capable of having a wiring harness fire at any time. I think most motorcycles made in the last 15 or 20 years, have a fuse or a circuit breaker protecting all the small wiring including the wire from the rectifier. Some bikes may have the main fuse built in as part of the starter relay (aka solenoid).
Also some cars/trucks use fuseable links in a similar way to prevent wiring harness fires.
mrtwowheel.................wire your bike as you wish. I hope your bike does not catch on fire.
I recommend you get a book on basic electricity circuit theory and study it, for your own safety.
Not sure about cars, trucks, and motorcycles in general, but in this particular layout the fuse does protect the battery. LOL. It isn't the primary reason for the fuse, but it does in fact have that effect.
pamcopete
Ride.Enjoy.Life is Simple
RG is correct. The other thing to consider is having the fuse go open circuit which can happen for a variety of reasons. With the fuse coming directly from the battery and the rectifier on the load side of the fuse, the alternator will continue to provide power to the load. However, without the battery in the circuit, the regulator will not have the stabilizing effect of the battery and could go nuts, producing very high voltages which can fry the electrical system without blowing any fuse. So, the best arrangement is to have a separate fuse from the rectifier to the positive terminal of the battery so if the battery fuse goes open circuit for any reason, you will lose all power to the bike but at least you will not suffer a bunch of fried components. A dead short from the load will blow the fuse and disconnect both sources of power from the load although a dead short will also deprive the alternator rotor of the current needed to produce power..
quote Paul;
"There is a problem with my SH's harness. The taillights are wired directly from the 20A fuse as shown in the diagram of Entry 3 by gggGary. The wiring is not suitable for high currents so it is possible that if it is shorted the wiring insulation may melt before the 20A fuse blows; Note - A short circuit may have a slight resistance resulting in close to 20A being drawn and this may not be sufficient for the 20A fuse to blow quick enough but just high enough to burn out a lighter wire and damage those bundled next to it in the harness."
Yes that is quite true Paul. My 1978 Special is wired much the same, except I have a "Light Checker" in series. I don't consider it to be much of a risk. If you want to add protection, you could install a 10 amp fuse in the blue wire, just as the blue wire leaves the ignition switch.
Here is a picture of some melted insulation on the headlight wiring of a 1980 XS650. We used to ride our bikes together, and he asked me to look into why his headlight came on as soon as the key was turned on. The Safety Relay should only switch on the head light after the engine starts. I unwrapped his harness and found the red/yellow and blue/black wires had over heated and melted until the 2 wires were shorted together, bypassing the SR. In the past, a PO may have been using a very high wattage head light; its hard to say. No fuse was blown, because he was using a normal head light wattage. I replaced the wiring for him.
"There is a problem with my SH's harness. The taillights are wired directly from the 20A fuse as shown in the diagram of Entry 3 by gggGary. The wiring is not suitable for high currents so it is possible that if it is shorted the wiring insulation may melt before the 20A fuse blows; Note - A short circuit may have a slight resistance resulting in close to 20A being drawn and this may not be sufficient for the 20A fuse to blow quick enough but just high enough to burn out a lighter wire and damage those bundled next to it in the harness."
Yes that is quite true Paul. My 1978 Special is wired much the same, except I have a "Light Checker" in series. I don't consider it to be much of a risk. If you want to add protection, you could install a 10 amp fuse in the blue wire, just as the blue wire leaves the ignition switch.
Here is a picture of some melted insulation on the headlight wiring of a 1980 XS650. We used to ride our bikes together, and he asked me to look into why his headlight came on as soon as the key was turned on. The Safety Relay should only switch on the head light after the engine starts. I unwrapped his harness and found the red/yellow and blue/black wires had over heated and melted until the 2 wires were shorted together, bypassing the SR. In the past, a PO may have been using a very high wattage head light; its hard to say. No fuse was blown, because he was using a normal head light wattage. I replaced the wiring for him.
Batteries are very rugged. If there was no 20 amp fuse, and you had a short to ground in the wiring, high current would flow, and the copper wiring would likely melt and thus open the circuit. If the wire did not go open circuit, and current kept flowing, the battery would fully discharge and likely could be recharged later. The fuse is not there to protect the very rugged battery.
LOL. I said the same -- but I added that in this circuit the fuse does have the additional effect of protecting the battery from a short. You're saying a short across the battery would burn in two and fix itself, and it might or might not, but it's uncontrolled -- it was not something consciously included in the design and the reason for not using thicker wire was not so that it would burn in two. You're saying a (I assume sustained) short across the "very rugged" battery is not a problem. Charge up a battery and short it with a jumper cable and lets see what happens. You're saying it won't hurt the battery, and if you're right it won't cost you anything.
