FRESH START: Alternator Wiring Upgrade Configuration

[Trevor]

Originally Posted by benebob

But again John, DOES the amount of amps that can run through the 10 gauge wires with the new higher frying alternator meet standard electrical practices? That is the more important question.

What constitutes "a higher frying alternator"? One that can pass higher current to fry other loads, or one capable of frying itself such that it it is likely that a lower resistance fault path to the battery will result?

The fusible link protects against any short circuit in the wiring to the alternator, or a short within the alternator. The link is also the last measure of protection within the distribution system. This will be the requirement to be satisfied first, in any official wiring practice or regulation.

Conversely a healthy alternator will be protected, to some extent against overload, but only against an overload due to a short, or partial short, at the battery or within the associated wiring. That is if the wiring is as per the manuals. The fusing within the distribution system protects the alternator from overload in that direction.

[Trevor]

Originally Posted by benebob

Already did Trevor. I'm just trying to put it in terms John can understand. Again the question that both Bill and I both raised has not been answered. If you can't answer it why did you bother to post? Why don't you go back and argue with others unless you can answer one simple question regarding a 10 gauge wire and 160 amps running through it.

If you will lucidly and accurately define your question by PM, I will answer it. Please also do so under you Christian name.

I have a question for you. Why are you cluttering up this special thread when it has been specifically started with but one topic in mind, i.e. HOW TO replace the wiring to the alternator? The fuse link rating being a secondary issue.

I also point out that by believing what you have stated below, you confirm a lack basic knowledge regarding the subject matter. You appear to hold the idea that the voltage regulator dissipates power, while the alternator continuously delivers maximum current. You state:-

“This is where you're electrical theories and reality differ. It does matter John, an alternator is not demand only it puts out its power based on engine speed and its output in relation to that engine speed. The regulator is the portion which bases it on demand not the alternator itself (even to this day a lot of cars don't have an internal regulator).”

N.B. I am arguing with no one. I am doing no more than ensuring that which is correct, is recorded.

[SVXRide]

Strangely enough, what Harvey (and earlier Trevor) has now suggested was running through my head not too long after John called me yesterday. As no one has been able to ascertain why our cars have 2 white wires, the only thing I could come up with was that they're basically like running two resistors in parallel, so why not gang them together? As Harvey (and Trevor) have noted, this keeps the protection in the system as originally designed.
(God, I hope this makes sense )
-Bill
p.s. another thing I thought of after talking with John was that he needs to make sure to carry spare FLs with him, just in case he runs into a problem while "on the road"

[benebob]

Originally Posted by Trevor

What constitutes "a higher frying alternator"? One that can pass higher current to fry other loads, or one capable of frying itself such that it it is likely that a lower resistance fault path to the battery will result?

The fusible link protects against any short circuit in the wiring to the alternator, or a short within the alternator. The link is also the last measure of protection within the distribution system. This will be the requirement to be satisfied first, in any official wiring practice or regulation.

Conversely a healthy alternator will be protected, to some extent against overload, but only against an overload due to a short, or partial short, at the battery or within the associated wiring. That is if the wiring is as per the manuals. The fusing within the distribution system protects the alternator from overload in that direction.

Trevor, go run 160 amps through any 10 gauge wire and have your marsh mellows ready.

As for my Christian name, if you're too clueless to know what it after what 10 years now then my God help you.

[oab_au]

Originally Posted by benebob

This is where you're electrical theories and reality differ. It does matter John, an alternator is not demand only it puts out its power based on engine speed and its output in relation to that engine speed. The regulator is the portion which bases it on demand not the alternator itself (even to this day a lot of cars don't have an internal regulator).

I agree with Benebob, they are different.

There is a big difference between a battery powered circuit and an alternator powered circuit, especially one that has lost the voltage control, as we have seen with the SVX system. A charged battery holds a set amount of electrical energy, if we put a load on it, the voltage will drop, and current is flowing. The load is turned off, and the voltage rises back to the original voltage.

An alternator that has a regulator failure that, has full current flowing in the rotor, will generate maximum magnetic field, and the energy output will rise with the rotational speed. Its voltage is only limited by the battery that will start charging higher. The current will only be limited by the circuit resistance.

In the SVX we have an alternator that is connected to the battery by a fusible link. Connected between the alternator and the link there are a number of circuits. When the regulator loses control the alternator goes flat out. The system voltage rises to about 17.5V, and the current is at the maximum 90 amps 80amps flowing through the link to the battery, and 10amps flowing in the connected circuits, a total of 1575watts. Watts = volts multiplied by amps, 17.5V X 90A = 1575W

This 1575watts is the energy that the alternator is generating; it is not just stored energy to run out, it is still being generated. If the fusible link blows, the 80 amps flowing to the battery stops, there is only the 10-amp circuit flowing current.

Due to the drop in amperage, the voltage will rise to 157 volts. 1575watts divided by 10amps = 157 Volts. But as this circuit now has 157 volts across it, the current flowing through it will be 157Volts divided by the resistance of these circuits. If the smaller circuits flowed 10 amps at 14 volts, they have a resistance of 1.4 ohms.
With 157 volts across them, they will flow 112 amps. 157V divided by 1.4 ohms = 112 amps.
It will continue to flow this current, till the circuits burn out. This is where the alternator is different; its output is only limited by the speed of rotation, and the reluctance of the stator metal.

Harvey.

[SSSVX]

Interesting, I love this thread, and hope it'll come to a good conclusion.

I like the way harvey's explanation in post #27.

Does John carry spare fusible links/fuses? At Reading 3,
I remember he carried spare bulbs for his ex-pearly.

[Trevor]

Originally Posted by benebob

Trevor, go run 160 amps through any 10 gauge wire and have your marsh mellows ready.

As for my Christian name, if you're too clueless to know what it after what 10 years now then my God help you.

Your posts throughout this topic are inaccurate. As you make a suggestion regarding something to which have not referred, your obtuse statement is derogatory, as well as being a case of baiting.

A question was put to you but has not been answered. The reasons for that question, you continue to multiply.

Whether or not I am aware of your Christian name is not the issue. The issue is one of courtesy and apparently beyond your knowledge in respect of etiquette. You say, “my god help you” I wonder who your god is?

Over a distance of three feet, 10 AWG would be suitable for a current of 200 Amps at 12 Volts DC, as stated within electrical engineering text I have on hand.

3 feet of 10 AWG copper wire has a resistance of 0.03054 Ohms, give or take a minute figure, depending on the grade of copper.

Voltage drop over 3 ft. would amount to slightly less than 1 volt at 160 Amps. DC continuous.

Power dissipation would equal 160 watts, radiated from a surface area of close to 75 sq. cm.

Fusing current equals 333 Amps over a factor of time, as stated within an electrical engineering text. i.e. as a fusible link, 10 AWG would be “slow blow” at this figure.

Unfortunately there is no hope of cooking any marsh mellows. What is more your tirade against John as below holds no water. On the basis of his lucid, well set out data on the subject, his knowledge is obviously superior to yours.

#8 But again John, DOES the amount of amps that can run through the 10 gauge wires with the new higher frying alternator meet standard electrical practices? That is the more important question.

#10 The wiring before the fusable link is the wiring I'm still refering to and you still haven't answered my question about it being able to handle worse case 160 amps. Both you and I know it won't. That's where the marshmellows will get the hottest!

#12 Again John you did not answer my question. What is stopping your car from burning if your regulator allows more amps to pass through your wiring BEFORE it is protected with a fusable link and trust me your regulator and/or alternator will fail much more often then a standard output alternator will.

#19 You're missing the point John, I'd hate to see your car damaged because of it! Please protect it right. You're one ground away from quite a few more amps than it can handle!

Trevor.

[oab_au]

Originally Posted by Francis

....woa , then what would u do if u were installing a high amp alternator ???

Just do it the same as Svxcess does.

Harvey.

[Trevor]

Originally Posted by SVXRide

Strangely enough, what Harvey (and earlier Trevor) has now suggested was running through my head not too long after John called me yesterday. As no one has been able to ascertain why our cars have 2 white wires, the only thing I could come up with was that they're basically like running two resistors in parallel, so why not gang them together? As Harvey (and Trevor) have noted, this keeps the protection in the system as originally designed.
(God, I hope this makes sense )
-Bill
p.s. another thing I thought of after talking with John was that he needs to make sure to carry spare FLs with him, just in case he runs into a problem while "on the road"

Greetings Bill,

The problem at this stage, is that we do not know all the termination points of the two white wires, so that we cannot confirm that they are in parallel throughout their length. I seem to recall a mention in the earlier thread, I think by John, indicating that the wires ran to each side of the fuse link. If so, this would parallel the link with another through circuit, which would be rather strange.

What we need is someone with a parts car, to pull off the fuse box and trace the circuits. The wiring diagram does not appear to be accurate. Are you on for this? I cannot help as my JDM car is different.

Having a beer at the moment, so here's cheers. Trevor.

[Trevor]

Originally Posted by oab_au

I agree with Benebob, they are different.

There is a big difference between a battery powered circuit and an alternator powered circuit, especially one that has lost the voltage control, as we have seen with the SVX system. A charged battery holds a set amount of electrical energy, if we put a load on it, the voltage will drop, and current is flowing. The load is turned off, and the voltage rises back to the original voltage.

An alternator that has a regulator failure that, has full current flowing in the rotor, will generate maximum magnetic field, and the energy output will rise with the rotational speed. Its voltage is only limited by the battery that will start charging higher. The current will only be limited by the circuit resistance.

In the SVX we have an alternator that is connected to the battery by a fusible link. Connected between the alternator and the link there are a number of circuits. When the regulator loses control the alternator goes flat out. The system voltage rises to about 17.5V, and the current is at the maximum 90 amps 80amps flowing through the link to the battery, and 10amps flowing in the connected circuits, a total of 1575watts. Watts = volts multiplied by amps, 17.5V X 90A = 1575W

This 1575watts is the energy that the alternator is generating; it is not just stored energy to run out, it is still being generated. If the fusible link blows, the 80 amps flowing to the battery stops, there is only the 10-amp circuit flowing current.

Due to the drop in amperage, the voltage will rise to 157 volts. 1575watts divided by 10amps = 157 Volts. But as this circuit now has 157 volts across it, the current flowing through it will be 157Volts divided by the resistance of these circuits. If the smaller circuits flowed 10 amps at 14 volts, they have a resistance of 1.4 ohms.
With 157 volts across them, they will flow 112 amps. 157V divided by 1.4 ohms = 112 amps.
It will continue to flow this current, till the circuits burn out. This is where the alternator is different; its output is only limited by the speed of rotation, and the reluctance of the stator metal.

Harvey.

It is stated that there is only a 10 amp circuit flowing current. The distribution circuits are each fused at 45 amps. Based on members comments regarding the need for a high output alternator, the average load will certainly far exceed 10 amps.

The system voltage is also stated as rising to about 75 amps. However this voltage can not be foreseen, as the load will vary according to the cars use. The stored energy available from the battery is compared with continuous energy from the alternator while ONLY a 10 amp load on line is claimed and this is incorrect.

Apart from the errors in the figures as stated, I am concerned that some members, as a result of statements made, may assume that the current from the battery is less likely to cause a dangerous situation, than current from the alternator. Whereas the reverse is the case.

A heavy lead, or say a screw driver, placed across the output of each, by way of a solid short, will prove the point in an emphatic and spectacular manner. In a situation of a near direct short, a 12 volt car battery, in this case one with a substantial capacity in ampere hours, becomes a frightening heat source and a very lively object.

A shorted alternator, while of concern, will be less of a problem as the windings, rectifier, or voltage regulator, will be quite quickly destroyed and open circuit, thus terminating current flow. This is likely to happen before the associated shorted circuit burns out.

[SVXRide]

Trevor,
Agreed. I wish the FSM's schematic was clearer. I think the SVreX might be a candidate for wire tracing...
-Bill

Originally Posted by Trevor

Greetings Bill,

The problem at this stage, is that we do not know all the termination points of the two white wires, so that we cannot confirm that they are in parallel throughout their length. I seem to recall a mention in the earlier thread, I think by John, indicating that the wires ran to each side of the fuse link. If so, this would parallel the link with another through circuit, which would be rather strange.

What we need is someone with a parts car, to pull off the fuse box and trace the circuits. The wiring diagram does not appear to be accurate. Are you on for this? I cannot help as my JDM car is different.

Having a beer at the moment, so here's cheers. Trevor.

[svxcess]

I have listened with keen interest and paid close attention to all that has been put forth in this thread.

The way my car is currently (with the 2 white wires connected directly to the battery) I have no problems at all and my voltmeter shows steady at 13.8V through most of the various loads I use. However, by doing this, I seem to have bypassed an important fusible link in the circuitry.


So here is my next and hopefully final piece of this modification.

Since the two white wires were originally flowing through the fusible link in the stock circuit, I decided to take Harvey's advice and remove them from the battery and just connect them to each other. This puts the circuit and protection back to its original design

The next thing is to isolate the alternator charge path from the rest of the circuitry, and provide protection for the 4 gauge wiring from the alternator to the battery through a protective device, either a ANL fuse or a MegaFuse


According to Trevor, I don't need to fit any other fuses to any other wiring as they were okay before the modification, and are still okay.



Besides the 100A AGU fuse, the other option is to use a Megafuse holder with a 150A slo-blo MegaFuse. The advantage is that it will connect to where my existing inline fuse holder is; the bases are identical and no changes in the wire are needed.


The main point of this portion of the modification is so that the alternator output is isolated from the rest of the circuitry, so if something malfunctions it won't blow relays and modules, which sometimes happens to the standard alternator and wiring that we have now. This high-output alternator has safety circuits in the regulator so that this may never be a problem, as failure is designed to go to an open circuit, rather than a short.


I hope to have all this in place by Reading, along with more statistics.
.

[LetItSnow]

Originally Posted by svxcess

The way my car is [currently]... I have no problems at all...

You can replace every fuse and fusible link in the car with straight-up wire and have no problems; this is a moot point.

Originally Posted by svxcess

This way I have to have a protective device that can accommodate just about the full output of the alternator if necessary.

This train of thought is backwards... Say you had a 5,000,000A alternator - do you want to protect the circuit for 5,000,000A? Not on your life!

If I'm reading you right, your selection of alternator is based upon reaching a ceiling output sooner, not a higher output altogether. Unless you're adding power consuming products to your car (high-draw stuff like amplifiers or who knows what), your protection amperage shouldn't change, because the draw won't change.

[svxcess]

Originally Posted by LetItSnow

You can replace every fuse and fusible link in the car with straight-up wire and have no problems; this is a moot point.

Benebob and others thought that I would have problems. That was what the heated discussion and friction was all about

This train of thought is backwards... Say you had a 5,000,000A alternator - do you want to protect the circuit for 5,000,000A? Not on your life!

If I'm reading you right, your selection of alternator is based upon reaching a ceiling output sooner, not a higher output altogether.

That's correct. That's what its always been about. When dealing with heavy electrical loads, a high-output alternator will not have to work as hard and is less prone to failure. I want most of my power avalable around idle, when it is the most important

Unless you're adding power consuming products to your car (high-draw stuff like amplifiers or who knows what), your protection amperage shouldn't change, because the draw won't change.

Correct again, Rob. If I don't add the 150A MegaFuse, I may just leave in my 80A inline fuse. If I happen to blow it I may go to 100A. The 4 gauge will handle that current easily.

The 150A rating was suggested to me by harvey "oab-au"

.................

[LetItSnow]

One more and I'm out of this one for good:

If you protect the car's circuitry from the alternator with a 140 or 150A fuse, fusible link, or breaker, if your alternator has a problem, I'm prone to believe that it won't be your only problem.

If you don't have hardware demanding more amps, don't jack the protection; it doesn't make any sense.