Electrical Issues

[299]

Can anyone enlighten us:-

 

-Alternator,regulator, stator coil, how are they worked? what cause them to be faulty?

 

-Batteries types, how are we able to maintain them?

 

-What are the common electrical problems that we are facing?

 

-What kind of fuse systems do we have?

[Strong Eagle]

So... are you asking about your specific model of bike or the operation and function of the parts you mentioned in general?

[snowparang]

Maybe I can shed some light...because I'm a recent owner of a VFR800, which is btw famed for electrical problems!

 

An alternator on most bikes is basically just a coil of wire. When the bike runs, a rotating stator/wheel, which has magnets on them, will spin in proximity to the coil. This will generate an AC current along the coil.

 

The alternator coil, with the AC current, cannot be used directly on the bike since bike electrics works on DC. Hence you need a rectifier to convert this AC voltage to a DC one. And usually on this rectifier it's also a built in regulator that maintain this voltage at approx 13V DC. Why the need to regulate? Because the faster the engine spins, the greater the AC voltage generated at the coil but we cannot convert the higher AC voltage into a higher DC voltage which will cook the bike electrical system.

 

And what cause them to be faulty? Usually heat. The regulator/rectifier - R/R(usually a single unit) regulates the voltage by converting excess voltage into heat. Hence that's why you'll find most R/R has fins for cooling.

 

As for the coil...well the coil on my VFR is actually a goner and I'm waiting for a spare one to be shipped from US of A. Will let you know once I open it up.

 

As for batteries, just make sure they don't get discharged completely (i.e. flat), which generally happens when you don't use the bike for some time. If that's the case, either prepare to change battery regularly or buy a battery charger/tender.

 

Other more common would be old or ineffective wiring, hence quite a substantial amt of energy is lost along the wires. Simple methods to solve this is grounding, or even replacing/upgrading the wire harness. But it shouldn't be that serious.

 

For more info, can visit VFRD. They have a whole subforum on electrical problems! http://www.vfrdiscussion.com/forum/index.php?showforum=7

 

Any CBR100RR riders wanna give their experience? I know they eat coils regularly!

[299]

So... are you asking about your specific model of bike or the operation and function of the parts you mentioned in general?

 

In general.

[299]

snowparang

 

Does over-revving do harms to the alternator coil and the rectifier?

 

what's the life-span of these two?

[Strong Eagle]

OK, a brief rundown of the equipment you mentioned.

 

An alternator is a device that produces electricity. It consists of multiple fixed coils of wire called the stator, and rotating coils of wire called the rotor. In theory, only one coil is needed for the stator and one for the rotor; in practice, there are six or more for each.

 

An alternator differs from a generator in three fundamental ways: First, a generator produces direct current while an alternator produces alternating current. Second, a generator uses permanent magnets in the stator to create a magnetic field, whereas there are no permanent magnets in an alternator (all magnetics generated from coils). Third, in a generator electricity is taken from the rotor, in an alternator, electricity is taken from the stator. Alternators are more efficient at producing electricity; hence you almost never see generators any more in auto/bike applications.

 

An alternator produces alternating current, which means the polarity of the electricity changes over time and rotation of the rotor. The images below show the simplest sine wave from a single pole alternator and the output of a typical bike or car alternator.

 

http://www.herbhost.com/revtec/sinewave2.bmp

 

http://www.herbhost.com/revtec/sinewave1.gif

 

The way an alternator works is as follows:

 

a) An electrical current is introduced into the rotor which creates a magnetic field in the rotor.

b) As the rotor spins, it generates an opposing magnetic field in the stator and electricity is produced from the stator (this is an extremely simplified version of how electricity is produced).

 

Now, the faster the rotor spins, the higher the output voltage from the stator will be for a given amount of current flowing through the rotor. The voltage is controlled by the addition of a voltage regulator. What this device does is measure the output voltage and then vary the amount of current to the rotor. Less current = less voltage, more current = more voltage. So, when your bike is at idle, rotor current will be at its maximum to generate the necessary voltage, and when the engine is at speed, the rotor voltage is reduced in proportion to the voltage being generated (which is a function of the total current draw of the bike).

 

It used to be that voltage regulators were mechanical make/break points but these days they are all electronic.

 

Next, your bike must run on direct current (DC), mostly because the battery can only handle DC current. So, you put a rectifier into the circuit. Through a clever design, it “flips” the negative sides of the AC voltage to positive. The diagram below shows what rectified DC voltage looks like.

 

http://www.herbhost.com/revtec/sinewave.gif

 

http://www.herbhost.com/revtec/sinewave3.gif

 

The most common failure for all parts is heat. To save space in an alternator, the wires are lacquered, not covering in plastic coating. Heat and/or vibration can cause the lacquer insulation to rub off causing a short. A second point of failure in an alternator is that the brushes which supply current to the rotor through slip rings become worn out and do not make good contact. A third, less encountered problem is bearing failure.

 

Heat is also the biggest source of failure for the voltage regulator and the rectifier. The semiconductor chips inside break down when it gets too hot.

 

Batteries for all cars and most bikes are the lead acid variety, using sulfuric acid and lead plates. Some have free liquid (mostly auto batteries) and some use absorbing materials in between the plates to hold the liquid. Still others use a gel like compound to hold the sulfuric acid; these are the ‘mount in any position’ batteries.

 

Lead/acid batteries come in maintenance free and ‘add water’ varieties. Maintenance free mostly means that an attempt has been made to control the escape of water and hydrogen from the battery which causes the liquid levels to drop. In other batteries you periodically add water to make up for lost liquid.

 

When the alternator is not running a fully charged lead/acid battery puts out 12.6 volts. When it is about 80 percent run down it will put out about 10.8 volts. A lead/acid battery requires about 13.6 volts across its poles in order to be charged, so the voltage regulator is set to output 13.6 to 14.2 volts to insure that the battery will charge.

 

The things that hurt a battery are: Loss of water, which causes the battery plates to be exposed to air where they very quickly become oxidized and no longer function properly. Another thing that hurts batteries is a very heavy current draw, especially extended, which can cause the plates to bend and buckle so that they touch each other, thereby creating a short. Third, leaving a battery fully discharged will cause the plates to begin to flake and they will not take a full charge after that. Finally, vibration can cause things to move around in the battery to create shorts or open circuits.

 

Over-revving won’t hurt the alternator, voltage regulator, or the rectifier. It just spins faster and the regulator adjusts rotor current to keep the voltage in an acceptable range.

 

There is not a lot that can be done to keep problems from arising. You don’t want to add parts or covers that would keep air flow from the alternator or the regulator/rectifier (sometimes separate, sometimes included as part of the alternator). Keep your battery topped up if it is not maintenance free, and make sure that it is properly tied down so that it does not vibrate too much. Make sure electrical connections (especially battery cables) are tight and clean.

[bikeyroo]

Will placing a fan to blow over the rectifier helps to prevent its failure?

[vfrT]

Maybe I can shed some light...because I'm a recent owner of a VFR800, which is btw famed for electrical problems!

 

 

Hi y'all

Sorry for off topic.

 

Just to put things into perspective... but I know that every bike have its unique weakness.

 

It is true that the VFR is known for rectifier problems - probably cos its pre-disposed to being well-used by its owner and thus causing the overheating which cause the burn out r/r. But other than that, most owners, including myself has little or no other 'electrical problems' except for normal wear & tear.

 

Your experience is quite unique.

 

 

cheers

[ANR Impex]

OK, a brief rundown of the equipment you mentioned.

.

.

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There is not a lot that can be done to keep problems from arising. You don’t want to add parts or covers that would keep air flow from the alternator or the regulator/rectifier (sometimes separate, sometimes included as part of the alternator). Keep your battery topped up if it is not maintenance free, and make sure that it is properly tied down so that it does not vibrate too much. Make sure electrical connections (especially battery cables) are tight and clean.

 

 

Some inaccuracies here:

The modern bike's alternator isn't field regulated like a car's. It has no moving parts, no brushes or slip rings to wear off. The regulation is pure by solid state electronics that convert excess power to heat. This is the one major contributor to failure.

 

An 80% full battery won't read as low as 10.8V open circuit voltage. More likely 12.5~12.7V. A fully trickled charged maintenance free open voltage V is around 12.9V.

 

Modern EFI bikes present a major problem for batteries. Carburetted bikes used to start fine even with open circuit voltages below 12V.

 

I have encountered a couple of EFI bikes that just refuse to start even when the battery has enough juice to crank strongly. The voltage dip on cranking resets the ECU and paralizes the fuel pump. The min open circuit battery voltage for modern EFI bikes need to be as high as 12.6V. And since we have a couple of VFR riders in this discussion, this is one such bike (VFR800)

 

The situation has gotten so bad and unpredictable that I soldered up a pair of compact jumper cables that'll fit in the compartment under my pillion seat. It is difficult to push start EFI bikes and can be really frustrating when a bike just refuse to start despite strong cranking and bright lights. Rescued 2 friends since, expecting many more to come with the way things are.

[snowparang]

An alternator is a device that produces electricity. It consists of multiple fixed coils of wire called the stator, and rotating coils of wire called the rotor. In theory, only one coil is needed for the stator and one for the rotor; in practice, there are six or more for each.

 

Second, a generator uses permanent magnets in the stator to create a magnetic field, whereas there are no permanent magnets in an alternator (all magnetics generated from coils). Third, in a generator electricity is taken from the rotor, in an alternator, electricity is taken from the stator. Alternators are more efficient at producing electricity; hence you almost never see generators any more in auto/bike applications.

SE, are you sure the magnetic field is generated by electrical means? I think most modern bikes have permanent magnet rotor. Mine does at least...

 

The situation has gotten so bad and unpredictable that I soldered up a pair of compact jumper cables that'll fit in the compartment under my pillion seat.

Hmm..jumpers...next items in my toolkit!

 

Will placing a fan to blow over the rectifier helps to prevent its failure?

I don't think a fan is much help but relocating the R/R to another place with better airflow will.

 

I've just noticed on 2 suzuki bikes (bandit and GSR400) that the R/R is mounted on the external of the bike, exposed to the elements. Hondas usually have them behind some cover. Does Suzukis' electrical system have a better reputation?

[snowparang]

Your experience is quite unique.

I do hope so! The previous owner of the bike has no problem either! But 1 week after changing hands, I was almost stranded somewhere in Kulai.

 

And funny enough, it's not the R/R but the coil that went kaput (possibly caused by a bad battery). Which is worst, cos there's no spares in Singapore. What's ironic is that I'm ordering a coil for a Honda bike from US....

 

I'm still riding the bike...just that I have to remove the battery and charge it everyday! And of course I try not to ride at night, since I don't wish to switch on the headlights....

[Strong Eagle]

Some inaccuracies here:

 

Thanks for the update on voltages. I was doing them from memory.

 

Certainly, regulators are solid state these days. And if it is a true alternator there must be slip rings on the rotor, othewise there is no way to get the excitation current into the rotor coils.

 

Starting problems with a low battery are not limited to EFI bikes. My bike uses carbs and an ECU for spark. It will turn over just fine but will never generate a spark with a low battery.

[Strong Eagle]

SE, are you sure the magnetic field is generated by electrical means? I think most modern bikes have permanent magnet rotor. Mine does at least...

 

 

If you have permanent magnets then you have a generator, and voltage is controlled by dumping the excess current to ground via the regulator.

 

An alternator uses an excitation current in the rotor to generate the magnetic field and to control alternator output. My bike is most definitely an alternator, as are most large displacement bikes, but I could not say for other bikes. What kind of bike do you have?

[snowparang]

If you have permanent magnets then you have a generator, and voltage is controlled by dumping the excess current to ground via the regulator.

 

An alternator uses an excitation current in the rotor to generate the magnetic field and to control alternator output. My bike is most definitely an alternator, as are most large displacement bikes, but I could not say for other bikes. What kind of bike do you have?

Mine is a 2000 Honda VFR800. When you open the alternator cover, does it not get 'stuck' to the casing due to the magnets?

 

Hmm...excitation current but where does the current comes from?

I'm not too sure if the terms 'generator' and 'alternator' are so specific. I'm sure I've seen AC and DC generators as well. My manual calls it alternator...

[bikeyroo]

I do hope so! The previous owner of the bike has no problem either! But 1 week after changing hands, I was almost stranded somewhere in Kulai.

 

And funny enough, it's not the R/R but the coil that went kaput (possibly caused by a bad battery). Which is worst, cos there's no spares in Singapore. What's ironic is that I'm ordering a coil for a Honda bike from US....

 

I'm still riding the bike...just that I have to remove the battery and charge it everyday! And of course I try not to ride at night, since I don't wish to switch on the headlights....

 

omg! You sure have the patience to charge it everyday! If I were you, I would go straight to Boon Siew and kow pei kow boo for not flying in the coil from Japan. I'm sure DHL can courier it within 1 day.....

[ANR Impex]

Thanks for the update on voltages. I was doing them from memory.

 

Certainly, regulators are solid state these days. And if it is a true alternator there must be slip rings on the rotor, othewise there is no way to get the excitation current into the rotor coils.

 

Starting problems with a low battery are not limited to EFI bikes. My bike uses carbs and an ECU for spark. It will turn over just fine but will never generate a spark with a low battery.

 

I believe the difference is in the names we call them by. In our system, anything that gives an AC output is an alternator. Bikes have alternator coils (stators) and are driven by permanent magnet rotors, hence there are no field windings and no need for excitation current.

 

I do not know if there are bikes that are exceptions to this, but the majority are this way, which is why we have so much poor charging problems when ridden in city conditions.

[Strong Eagle]

I believe the difference is in the names we call them by. In our system, anything that gives an AC output is an alternator. Bikes have alternator coils (stators) and are driven by permanent magnet rotors, hence there are no field windings and no need for excitation current.

 

I do not know if there are bikes that are exceptions to this, but the majority are this way, which is why we have so much poor charging problems when ridden in city conditions.

 

Well, I learned something new today, thanks to you, ANR. Looked up 'permanent magnet alternator' and indeed, such a beast exists, and for a low wattage system, it makes sense.

 

You are indeed correct. It is the rotor that has the permanent magnets so it is a brushless device since power comes from the stator. And since it uses magnets it draws no excitation current power.

 

http://www.dangerouslaboratories.org/altp1.html

[honda475]

hi all,

 

analysing all the above info provided,,

 

does it make sense to say that the headlight shld be left ON all the time ,

as to help preserve the re-actifier, ? ? ?

 

reason being, electrical energy not used will be converted to Heat energy and hence cook the re-actifier.....

[snowparang]

omg! You sure have the patience to charge it everyday! If I were you, I would go straight to Boon Siew and kow pei kow boo for not flying in the coil from Japan. I'm sure DHL can courier it within 1 day.....

Well...I'm a cheapo. And I wanna try the aftermarket ones which the VFR riders in US are raving about.

 

1 more week and it should arrive!

[bikeyroo]

Well...I'm a cheapo. And I wanna try the aftermarket ones which the VFR riders in US are raving about.

 

1 more week and it should arrive!

 

 

oic.........

[ANR Impex]

hi all,

 

analysing all the above info provided,,

 

does it make sense to say that the headlight shld be left ON all the time ,

as to help preserve the re-actifier, ? ? ?

 

reason being, electrical energy not used will be converted to Heat energy and hence cook the re-actifier.....

 

Yes, but then if your bike is a 2B bike that has weak charging, you compromise your battery this way. The traffic rule requires you to keep your lights on anyway.

 

Don't waste time worrying about rectifiers, those models that will fail do so because of poor design and there is really nothing you can do to prevent it from failing. The models with good design just go on and on, even with enough heat generated to melt the plastic wiring socket attached to it, because my own bike is well known for doing this.

 

All you can do it is to check for tight contact at the plug and prevent corrosion.

[snowparang]

The models with good design just go on and on, even with enough heat generated to melt the plastic wiring socket attached to it, because my own bike is well known for doing this.

What's your bike btw? Maybe I'll wire up your R/R if it's that good instead of OEM ones!

[ANR Impex]

03 R6. I am afraid the output cannot support VFR, it rated at 35A. With the floodlight that VFR has for headlights (4 x H7?), that alone is taking up more than half of the 35A. My bike is struggling to charge with hi beam on (2 x H7) even at high rpms (>10k).

 

I read about your problem, just want to add that in the process of fixing up your coil, you might want to check for any oxidised high current DC wirings and ensure all the female connectors fit tightly onto the male spades. These are often the contributing factors to your coil burning out.

[vfrT]

What's your bike btw? Maybe I'll wire up your R/R if it's that good instead of OEM ones!

 

A mate of mine riding a 99 EFI upgraded his rr to one from a Hayabusa. It is a heavier duty one and is resistant to the dreaded fry. He run to Thailand regularly and uses the NSH like a short cut and has no problem since.

 

Me - i wire up a fan to my r/r for the stop and go traffic in Sg - tho it did not prevent the inevitable but perhaps prolong life a bit.

[Nicholai]

A mate of mine riding a 99 EFI upgraded his rr to one from a Hayabusa. It is a heavier duty one and is resistant to the dreaded fry. He run to Thailand regularly and uses the NSH like a short cut and has no problem since.

 

Me - i wire up a fan to my r/r for the stop and go traffic in Sg - tho it did not prevent the inevitable but perhaps prolong life a bit.

 

Is a Hayabusa R/R more robust than VFR's?