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Old 18-07-18, 08:07 PM   #71
Bibio
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Default Re: Erratic ignition now no power, no start

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.
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Old 18-07-18, 08:11 PM   #72
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Default Re: Erratic ignition now no power, no start

Quote:
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.


Good to know thanks. Maybe Iíll fit some heated grips to use up some power


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Old Today, 12:18 AM   #73
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Default Re: Erratic ignition now no power, no start

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!!!!!
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Old Today, 06:45 AM   #74
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Default Re: Erratic ignition now no power, no start

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!!!!!


So a faulty battery could cause a increase in current and melt wire/connector?


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Old Today, 07:21 AM   #75
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 Today, 12:47 PM   #76
Bibio
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Default Re: Erratic ignition now no power, no start

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!!!!!
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 Today, 01:10 PM   #77
SV650rules
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Default Re: Erratic ignition now no power, no start

Quote:
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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