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Old 20-07-18, 07:21 AM   #71
Yellow650Loz
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Default Re: Erratic ignition now no power, no start

Quote:
Originally Posted by BigTon View Post
So a faulty battery could cause a increase in current and melt wire/connector?


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Not ordinarily...... the charge system would compensate for the low output. Unless the reg/rec was burnt out too, or the stator. That would provide a scenario where common voltage could drop so far.
That being said, I've never known a faulty stator/Reggie rec/battery to melt wiring, not on it's own.
From what I've read .... yes I've skipped through a little.

You've got more than 70VAC between the pins from the stator resistance between pins is between 0.2 - 0.5

You tested the reg rec and found a dead diode, as the system wasn't charging properly it will have killed the battery.


Which wire was melted, was it?

White/bl stripe
Black/wh stripe
Red
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Old 20-07-18, 12:47 PM   #72
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Default Re: Erratic ignition now no power, no start

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Originally Posted by Yellow650Loz View Post
I think there's a few here mistaking voltage for current.
If the voltage drops then the current draw will be higher.

I.e.

55w @ 12V DC = 4.583 Amps
That's basically one headlamp bulb on a battery and engine off

55w @ 14.9V DC = 3.691 Amps
That's the same bulb but this time the battery is charging....the engine is running.

It's the current that overheats wiring and connectors, not voltage.
Now it could have been a corroded connector that's caused voltage drop and so the current draw has increased. However, I would be cautious as to why it melted in the first place, jump starting a motorcycle from a car is fine. Running or otherwise.

Please don't ever try jump starting a car from a motorcycle though!!!!!
100% correct. but its easier to get people to check problems using voltage without adding ohms law into the equation.

it would be nice to have a proper electrical/electronics expert on the forum.
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Old 20-07-18, 01:10 PM   #73
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Default Re: Erratic ignition now no power, no start

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Originally Posted by Bibio View Post
as long as all three outputs are the same and MORE than 70VAC and less than 90VAC you have a healthy stator.

the more voltage the stator kicks out the more the regulator has to work so produces a little more heat.

contrary to popular belief its actually bad to run the bike without your lights on. you want to use as much power as you can without sacrificing charging/ignition system. once a battery is fully charged it should only need a trickle from the RR to keep it healthy.
+1


Any power the stator is producing that is not being used (loading up the system will reduce stator voltage) will have to be dumped by R/R and the only way it can dump this is by means of heat. Also as R1ffRAff has said many times any corrosion on R/R terminals will cause higher resistance and turn current flowing through the terminals into heat. This is a vicious circle = the hotter the terminals get the more they corrode - the more they corrode the higher the resistance gets and the hotter they get, this heat is conducted back into R/R and its components can get into thermal runaway - the diodes no longer block like they should and fail, and solid state bits like diodes always fail to a short circuit condition ( they conduct power when they should not) the only hope is that the wire connecting diode fails like a fuse - otherwise other things get taken out .

A car alternator works in a different way to the one on a motorbike, the car alternator has a coil on the rotor that gets excitation power via brushes and sliprings (very low current) - the power output of the alternator can be controlled relative to demand by increasing or reducing the magnetic field produced by the rotor coil. A motorbike alternator is really a pretty dumb bit of kit that just churns out power, and if this power is not used it has to be dumped by R/R in the form of heat.

Quote:
Originally Posted by Yellow650Loz View Post
I think there's a few here mistaking voltage for current.
If the voltage drops then the current draw will be higher.

I.e.

55w @ 12V DC = 4.583 Amps
That's basically one headlamp bulb on a battery and engine off

55w @ 14.9V DC = 3.691 Amps
That's the same bulb but this time the battery is charging....the engine is running.

It's the current that overheats wiring and connectors, not voltage.
Now it could have been a corroded connector that's caused voltage drop and so the current draw has increased. However, I would be cautious as to why it melted in the first place, jump starting a motorcycle from a car is fine. Running or otherwise.

Please don't ever try jump starting a car from a motorcycle though!!!!!

A bulb may be a bad example because they are non-linear and resistance changes as filament temperature changes https://www.eetimes.com/author.asp?s...doc_id=1331961 - when power is first applied a filament bulbs draws an 'inrush current' many times greater than its running current, this is because with a cold filament the resistance is much lower than with a hot filament (reason why most bulbs blow when power is first switched on rather than when they are hot). The reason why a filament bulb in your house can trip the circuit breaker when it blows is that once the filament breaks it causes an electric arc to form, the resistance of the arc is very low compared to filament and so a lot of current can flow.

If the 55 watt bulb is replace with a standard resistor with fairly flat resistance / temperature characteristics then as the voltage increases the current flowing will increase in direct proportion to applied voltage. Once you quote a wattage then things change because a 55watt bulb designed to work at 6v will have to have half the resistance to allow double the current to flow than the same bulb designed to work at 12volts.

If a connector gets corroded it will cause higher resistance which will try to make current drop, but the problem is that as the voltage across the connector increases this will increase the heating effect on that connector, which with a very small area to dissipate the temperature quickly builds up, and flows back into parts of RR that do not contact heatsink, if added to this the RR is trying to compensate by maintaining a certain voltage at its terminals and voltage drop across external connector means RR will try to compensate by increasing voltage.
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Last edited by SV650rules; 20-07-18 at 01:51 PM.
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Old 20-07-18, 08:50 PM   #74
Yellow650Loz
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Default Re: Erratic ignition now no power, no start

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Originally Posted by Bibio View Post
100% correct. but its easier to get people to check problems using voltage without adding ohms law into the equation.

it would be nice to have a proper electrical/electronics expert on the forum.
Hmmm, if they're competent enough to tinker then they should understand what they're tinkering with. Afterall, were only trained by experience anyway.
It's a simple enough principal, it's the diagnostic that takes the brain power but that's why the OP is here anyway for diagnostic advice...

I couldn't call myself an expert anything, more of a Jack of all trades. Thanks though that did my ego a boost
Seriously though, I'm just happy to ward off the scrap heap for as many older vehicles as possible along the way.
I learn something new with every (New to me) bike car or lorry

I wasn't referring to you in the post about the confused voltage/current thing. You've been spot on
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Old 20-07-18, 09:49 PM   #75
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Default Re: Erratic ignition now no power, no start

Any power the stator is producing that is not being used (loading up the system will reduce stator voltage) will have to be dumped by R/R and the only way it can dump this is by means of heat.

Spot on

Also as R1ffRAff has said many times any corrosion on R/R terminals will cause higher resistance and turn current flowing through the terminals into heat. This is a vicious circle = the hotter the terminals get the more they corrode - the more they corrode the higher the resistance gets and the hotter they get,

Also spot on

this heat is conducted back into R/R and its components

The increased current draw from the R/R will result in less wasted. Generally; as you've said the more current to waste the hotter the R/R runs meaning a higher current draw will result in a cooler R/R.
The amount of heat "conducted" back through a vehicle wiring system is so miniscule it's not worth mentioning.....


A bulb may be a bad example because they are non-linear and resistance changes as filament temperature changes

Correct, as the temperature increases the resistance increases, just as with wiring, starter motors, coil packs, pumps even resistors
The reason this was used as an example is because in real world scenarios we will rarely see a random resistor drawing that many watts apart from heater blower motors, bulbs are very common for all the obvious reasons


- when power is first applied a filament bulbs draws an 'inrush current' many times greater than its running current, this is because with a cold filament the resistance is much lower than with a hot filament (reason why most bulbs blow when power is first switched on rather than when they are hot).

Yup, it's called peak current draw and then nominal current draw.
In my experience however, (600-1000 miles a week in a lorry) bulbs tend to fail due to harsh bumps....hot filament, quick jolt from a bump and the almost molten tungsten let's go.


The reason why a filament bulb in your house can trip the circuit breaker when it blows is that once the filament breaks it causes an electric arc to form, the resistance of the arc is very low compared to filament and so a lot of current can flow.

AC and DC work differently, with an AC system we deal with higher voltages in order to use solid core wherever possible. Electrons move over the outside of conductors with only a few exceptions and so the surface area is greatly reduced, thus can handle a lower current.
AC has more of a tendancy to arc due to the magnetic field created, I won't go too far into this as it isn't relevant to the OP, the first discharge lamps were DC and VERY unreliable due to the high current required to create the arc, AC ballasts are far more reliable and so the lower current draw is far more forgiving on it's components, especially within the discharge capsule.


If the 55 watt bulb is replace with a standard resistor with fairly flat resistance / temperature characteristics

I presume you mean using a resistor with 5% tolerance.....one with a gold band?


then as the voltage increases the current flowing will increase in direct proportion to applied voltage.

The current will only increase if there is a current draw......I.e. a bulb, motor, heating element ect. Increasing the voltage will only serve to apply more or less voltage to the device in question.

Once you quote a wattage then things change because a 55watt bulb designed to work at 6v will have to have half the resistance to allow double the current to flow than the same bulb designed to work at 12volts.

Spot on

If a connector gets corroded it will cause higher resistance which will try to make current drop, but the problem is that as the voltage across the connector increases this will increase the heating effect on that connector, which with a very small area to dissipate the temperature quickly builds up, and flows back into parts of RR that do not contact heatsink, if added to this the RR is trying to compensate by maintaining a certain voltage at its terminals and voltage drop across external connector means RR will try to compensate by increasing voltage.

You had so much right and changed your mind for the summary
If a connector gets corroded it will cause a higher resistance.....this will drop the VOLTAGE at the load which will increase the current drawn......please see ohms law for ref.
As the current increases this will increase the temperature of the corroded connector and further increase the resistance.
The amount of heat that can be physically conducted back to the R/R is miniscule. I won't say it can't be conducted back but if I heat just the tip of a length of say 14AWG wire to solder to, or get it cherry red.....20CM away from that point will be ambient or close to. Either way it's negligible. Consider that diodes are generally ok just over 70 deg c, if they weren't then the processor I'm your computer would fail about 10 seconds after switching on.
Having said that, as the old proverb goes. A candle that burns twice as bright lasts only half as long; yes, the hotter something runs, it's working lifespan will be reduced but we're talking about an R/R it's designed to run that hot.
The R/R is doesn't try to compensate, if the voltage drops below 13.5vdc with the lamps on high beam at 5000rpm then it's out of spec; or the charge systems components are unsuitable for the current load required. This is the reason the stator was upgraded on the injection bikes to circa 300w IIRC ...... Its got more electrics to run and therefore more load. The only thing it will do is stop feeding so much current and waste this off as heat.



I lost the quote bubbles somewhere along the way so I've underlined my annotations, perhaps if I ask very nicely....a mod might clean it up for me

SV650rules I hope this helps you as well as the OP or anyone in the future reading this thread.
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Old 21-07-18, 07:56 AM   #76
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Default Re: Erratic ignition now no power, no start

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Originally Posted by Seeker View Post
With DC they use the whole conductor, with AC; the higher the frequency the more they migrate towards the surface skin of the conductor.
Someone was listening in their physics lessons
In practice though, theres no such thing as a perfect conductor.
Yeah, as the frequency increases the charge density increases and the electrons are observed at the surface of a 'Perfect' conductor.
However in DC vehicle applications we use stranded 'flex' as this increases the total surface volume, reducing the need for massive solid core cables. Obviously there's the requirement for it to be flexible also.
I love a good physics discussion, but it doesn't help the OP
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Old 21-07-18, 09:31 AM   #77
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Default Re: Erratic ignition now no power, no start

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Originally Posted by Yellow650Loz View Post

You had so much right and changed your mind for the summary [IMG]file:///C:\Users\Comet\AppData\Local\Temp\msohtmlclip1\01\ clip_image001.gif[/IMG]
If a connector gets corroded it will cause a higher resistance.....this will drop the VOLTAGE at the load which will increase the current drawn......please see ohms law for ref.
As the current increases this will increase the temperature of the corroded connector and further increase the resistance.
The amount of heat that can be physically conducted back to the R/R is miniscule. I won't say it can't be conducted back but if I heat just the tip of a length of say 14AWG wire to solder to, or get it cherry red.....20CM away from that point will be ambient or close to. Either way it's negligible. Consider that diodes are generally ok just over 70 deg c, if they weren't then the processor I'm your computer would fail about 10 seconds after switching on.
Having said that, as the old proverb goes. A candle that burns twice as bright lasts only half as long; yes, the hotter something runs, it's working lifespan will be reduced but we're talking about an R/R it's designed to run that hot.
The R/R is doesn't try to compensate, if the voltage drops below 13.5vdc with the lamps on high beam at 5000rpm then it's out of spec; or the charge systems components are unsuitable for the current load required. This is the reason the stator was upgraded on the injection bikes to circa 300w IIRC ...... Its got more electrics to run and therefore more load. The only thing it will do is stop feeding so much current and waste this off as heat.



I lost the quote bubbles somewhere along the way so I've underlined my annotations, perhaps if I ask very nicely....a mod might clean it up for me [IMG]file:///C:\Users\Comet\AppData\Local\Temp\msohtmlclip1\01\ clip_image002.gif[/IMG]

SV650rules I hope this helps you as well as the OP or anyone in the future reading this thread.
Not helped at all…………………….
You are having a laff right ? if you increase resistance anywhere in a circuit and voltage stays the same current is always going to drop (see Ohms law I = V/R if the numerator stays the same (V) and the denominator gets larger (R) the value of result (I) has to get smaller. You are making the mistake of keeping the 'wattage' at the load at eg 55watt, and sure enough to maintain 55watt at a lower voltage the current would have to increase (W-V*I) but as the voltage drops that 55watt bulb will just get dimmer, and while the number on the bulb may still say 55watt the bulb will not produce 55 watt of light because it is designed to be 55watt at 12.5 volts.


Quote:
Originally Posted by Yellow650Loz View Post

AC and DC work differently, with an AC system we deal with higher voltages in order to use solid core wherever possible. Electrons move over the outside of conductors with only a few exceptions and so the surface area is greatly reduced, thus can handle a lower current.
AC has more of a tendancy to arc due to the magnetic field created, I won't go too far into this as it isn't relevant to the OP, the first discharge lamps were DC and VERY unreliable due to the high current required to create the arc, AC ballasts are far more reliable and so the lower current draw is far more forgiving on it's components, especially within the discharge capsule.


If the 55 watt bulb is replace with a standard resistor with fairly flat resistance / temperature characteristics

I presume you mean using a resistor with 5% tolerance.....one with a gold band?

It is only at pretty high frequency you get a ‘pipe’ effect with electrons where they tend to use outside of conductor, at 50Hz no probelmo ( they use solid core cable for normal domestic wiring). The reason a solid core is used in house wiring and not in machinery and vehicles is that solid cores tend to break when they are subject to movement and vibration, where stranded ‘flexibles’ do not’.

The tolerance of a resistor has nothing to do with whether it has a low or a high positive or negative coefficient of resistance, it is all down to what it is made from – when I said a standard resistor it was ‘a standard resistor that is designed (as they are) to not change resistance much as it got hotter or cooler’ (which is the opposite of a bulb filament the resistance of which changes massively as it heats up).

Actually DC has more of a tendency to arc than AC, simply because an sine wave (AC) passes through zero volts once every half cycle ( every 10mSec at 50 Hz) as it transitions from positive to negative – this will quench any arc (an arc cannot exist without voltage), DC only passes through zero volts when it is turned off, so once an arc is established there is nothing to quench it.
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Last edited by SV650rules; 21-07-18 at 09:36 AM.
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Old 21-07-18, 10:56 AM   #78
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Default Re: Erratic ignition now no power, no start

Not helped at all…………………….
You are having a laff right ? if you increase resistance anywhere in a circuit and voltage stays the same current is always going to drop (see Ohms law I = V/R if the numerator stays the same (V) and the denominator gets larger (R) the value of result (I) has to get smaller. You are making the mistake of keeping the 'wattage' at the load at eg 55watt, and sure enough to maintain 55watt at a lower voltage the current would have to increase (W-V*I) but as the voltage drops that 55watt bulb will just get dimmer, and while the number on the bulb may still say 55watt the bulb will not produce 55 watt of light because it is designed to be 55watt at 12.5 volts.


Might I suggest you're beyond help then
If you increase the resistance in a circuit the voltage will drop. This isn't a textbook mate, the drop in voltage will cause a higher current draw.
It's 55w nominal, that's what it's rated at...... you're struggling to get this, I won't keep explaining how this all works in the real world. When you mess up the electrics on yours, let me know....I'll buy it





It is only at pretty high frequency you get a ‘pipe’ effect with electrons where they tend to use outside of conductor, at 50Hz no probelmo ( they use solid core cable for normal domestic wiring). The reason a solid core is used in house wiring and not in machinery and vehicles is that solid cores tend to break when they are subject to movement and vibration, where stranded ‘flexibles’ do not’.

The tolerance of a resistor has nothing to do with whether it has a low or a high positive or negative coefficient of resistance, it is all down to what it is made from – when I said a standard resistor it was ‘a standard resistor that is designed (as they are) to not change resistance much as it got hotter or cooler’ (which is the opposite of a bulb filament the resistance of which changes massively as it heats up).

Actually DC has more of a tendency to arc than AC, simply because an sine wave (AC) passes through zero volts once every half cycle ( every 10mSec at 50 Hz) as it transitions from positive to negative – this will quench any arc (an arc cannot exist without voltage), DC only passes through zero volts when it is turned off, so once an arc is established there is nothing to quench it.

Again, I won't repeat what I wrote. I have a job to do
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Old 21-07-18, 11:49 AM   #79
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Default Re: Erratic ignition now no power, no start

@Yellow650Loz

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Old 21-07-18, 12:09 PM   #80
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Default Re: Erratic ignition now no power, no start

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If you increase the resistance in a circuit the voltage will drop. This isn't a textbook mate, the drop in voltage will cause a higher current draw.
I'm not sure where you've got this from, if the voltage across a (relatively) fixed resistance load drops, the current will also drop.

With a corroded connection, it's effectively an additional load in the circuit. Because of this, there's a voltage drop across it and therefore power consumed which must be dissipated as heat.

The easiest way to diagnose a problem is to check the voltages between the battery, R/R and load and either side of connectors between. In a perfect world they should all be the same. If there's a significant difference between any two, then your problem will be between the two points. The Haynes manual (if I remember correctly) gives acceptable voltage differences.

The same applies to the earth. A garage once needlessly replaced the starter motor on my car because they swore it was dead as they could see a voltage on it. It turned out that the earth bonding was shot and it was just the clutch cable providing a path back to the battery -ve.
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