MAD/Nacho Electrical Wiring mods

[72RoadrunnerGTX]

What's the advantage on keep the original path on alt side at least? The main splice inside the cab will be still beng feeded from alt by two 12 gauge wires, the one coming from bulkhead and the line coming from ammeter where you are installing the parallel path, thing what won't happen removing the stock one and installing just the larger bypass through the firewall, where is true you can use a 8 gauge wire but the main splice will be still getting just the 12 gauge wire between amm and splice.

Have to challenge one of your points, never suggested removing the original ammeter to splice run, it needs to remain. At 12 gauge, it’s more than adequate for original factory electrical loads, any additional loads should then connect at the alt side ammeter stud or at some point between there and the alternator stud. Still not convinced? you could remove the 12ga splice to bulkhead connector, that would be by-passed, connect it to the alt side ammeter stud, that would double up the splice feed but is really not necessary for stock loads only. There is no electrical need to leave the original charge wires in place if performing this wiring upgrade.

Example of additional non-factory loads.

 

[Mopar4Speed]

What's the advantage on keep the original path on alt side at least? The main splice inside the cab will be still beng feeded from alt by two 12 gauge wires, the one coming from bulkhead and the line coming from ammeter where you are installing the parallel path, thing what won't happen removing the stock one and installing just the larger bypass through the firewall, where is true you can use a 8 gauge wire but the main splice will be still getting just the 12 gauge wire between amm and splice.

So if I am understanding correctly, you are suggesting leaving the 12ga wire in place and running parallel. Running the parallel is just to take the load (if and when it is needed) but connecting the the new charge wire to ammeter with the oe wire removed. I would connect the cab/dash side oe wiring 12ga feed to the ammeter stud with the new 6ga alternator wire. From the outside the car would look stock with the wiring i would just leave the black wire de-pinned from the dash harness at the bulkhead. My car is low optioned so i shouldn't have any crazy power needs but i am still hesitant on using the bulkhead connection. Only thing i am upgrading is the radio to retro sound unit.

 

[72RoadrunnerGTX]

Too easy to un-wrap the engine compartment harnesses and replace the wires, re-wrap for a clean factory appearance. Just did it again on a new M&H harness for the current E-body project.

 

[Nacho-RT74]

you could remove the 12ga splice to bulkhead connector, that would be by-passed, connect it to the alt side ammeter stud, that would double up the splice feed

True and I thought on that option once too but if you don't want to get deeper into the wiring still IMHO there is not reason to remove or modify the existant one yet if is still in working order... at the end goes at each own. I still have the stock system on my car reinforced with the parallel path and haven't had any problem since 10 or 12 years now ( althought my car is parted out at this moment since some years ) being a driver with A/C.

In my case, I have relay upgrades into the cab ( 6 in total ) being feeded from amm stud, so keep the stock black wire helps.

So if I am understanding correctly, you are suggesting leaving the 12ga wire in place and running parallel. Running the parallel is just to take the load (if and when it is needed)

as I mentioned, I still have the stock one ( because I rebuilt all my harnesses to stock specs ) then upgraded with a parallel path as the diagram I posted. I can make a new diagram of what will be my next wiring job when my car is reassembled ( hoping by the end of the year ) for easier fuse link splice job, which is not on the thread you took the diagram.

so I have, the stock black 12 gauge wire from alt, used an 8 gauge wire on parallel path BUT JUST BECAUSE I had that 8 gauge wire in hands without need to buy anything. Actually keeping the stock 12, a 10 parallel wire would be quite enough

then also kept the stock 12 red wire with the stock 16 fuse link, and run a 10 gauge wire with a 14 fuse link both tied up to the starter relay stud. This is not good ( times comes with new learnings ) because dual fuse link will take LOOOONG time to blown and will be late for wiring installation when a short comes. Better just keep one fuse link... 14 gauge. I'm thinking on simply remove the stock fuse link and red wire and just keep the 10 gauge red one with 14 fuse link. With an upgraded alt, 85-90% of the time the alt will feed everything and batt will be playing just 15-10% of the time, so a GOOD single path on batt side of ammeter will be enough.

As I mentioned, to each own or prefference. You can cook a pork in a dozen diff ways... I'm pretty sure this will work SAFE for me and pretty sure will work for any average car to work with an upgraded alternator. And as I mentioned my car was ( is ) and will still be a driver with this wiring configuration being safe.

 

[funknut]

Apologies if this is too simplistic but I'm trying to understand and summarize the practicality of ammeter vs. voltmeter. Please correct where I'm off.

As I understand it the only time the ammeter should see high current is when the charge circuit is flowing current. Typically this only happens when the battery is discharged or is failing and can't hold a charge well.

Ammeters will show the health of the charging system (alt, voltage reg. and battery) in real time. Ammeter showing excessively high means the battery is low, is not holding a charge, or something is draining the battery faster than the alternator can keep up (too many accessories or possibly a short?), or possibly a problem with the voltage reg.

Ammeter showing low means the alt is not charging which may point to a problem with the alt or voltage reg.

Voltmeters may show high or low if there's a problem with the voltage regulator, or low if the battery is drained and not charging.

Given the above, voltmeters are good for identifying over-voltage problems but worse than ammeters at detecting real-time problems with the charging system because they report on the symptom, (reduced voltage at the battery due to it being drained and not charging) and don't show a low reading until whatever root problem has persisted long enough to drain the battery.

The risk/concern with ammeters is if the ammeter fails open it prevents the car from charging and you're dead on the side of the road. If it fails closed then it could burn the car down. One advantage of voltmeters is they suffer from neither of those problems.

Hopefully the above is relatively correct.

 

[72RoadrunnerGTX]

The risk/concern with ammeters is if the ammeter fails open it prevents the car from charging and you're dead on the side of the road. If it fails closed then it could burn the car down. One advantage of voltmeters is they suffer from neither of those problems.

I’ll address this one, to be clear, the ammeter info to follow excludes the late-seventies plastic framed cost cutting Chrysler/Dodge truck ammeters. Also keep in mind nothing about these cars were ever designed as to be still on the road fifty-sixty years later.

“fails open”, not likely, the internal bus/shunt is pretty stout, would take mega amps to burn it open completely. The stud heads to bus contact area can develop moisture caused corrosion that can add resistance and generate some heat. Clean up and soldering the stud heads to the bus can alleviate that issue. The ammeter is mounted to the pot metal cluster frame with the same studs and fiber insulators. Over tightening the studs can crush the fiber insulators and lead to the loosing of the stud nuts (more resistance) and the failure of the insulators. Contact with the cluster frame will generate heat and could lead to an over-current damage elsewhere in the charging circuit (dead short). Maintenance and proper torque of the ammeter connection insulators & nuts is crucial, tight but not too tight it crushes the insulators.

“failed closed”, a healthy ammeter is internally electrically “closed”, these ammeters on their own, is not going to burn down a car. Poor ammeter connections & insulators, will create high resistance and/or shorts, with enough current flow, will generate significant heat and can burn things. Again, many later seventies plastic framed ammeters have melted and have likely burned dashes from resistance generated heat.

Voltmeters can, and do, fail too. Typically, when installed correctly-fused, they would not have access to enough current to be a problem when they fail. Information provided by a voltmeter is limited, little more than an idiot light.

 

[Nacho-RT74]

I’ll address this one, to be clear, the ammeter info to follow excludes the late-seventies plastic framed cost cutting Chrysler/Dodge truck ammeters. Also keep in mind nothing about these cars were ever designed as to be still on the road fifty-sixty years later.

“fails open”, not likely, the internal bus/shunt is pretty stout, would take mega amps to burn it open completely. The stud heads to bus contact area can develop moisture caused corrosion that can add resistance and generate some heat. Clean up and soldering the stud heads to the bus can alleviate that issue. The ammeter is mounted to the pot metal cluster frame with the same studs and fiber insulators. Over tightening the studs can crush the fiber insulators and lead to the loosing of the stud nuts (more resistance) and the failure of the insulators. Contact with the cluster frame will generate heat and could lead to an over-current damage elsewhere in the charging circuit (dead short). Maintenance and proper torque of the ammeter connection insulators & nuts is crucial, tight but not too tight it crushes the insulators.

“failed closed”, a healthy ammeter is internally electrically “closed”, these ammeters on their own, is not going to burn down a car. Poor ammeter connections & insulators, will create high resistance and/or shorts, with enough current flow, will generate significant heat and can burn things. Again, many later seventies plastic framed ammeters have melted and have likely burned dashes from resistance generated heat.

Voltmeters can, and do, fail too. Typically, when installed correctly-fused, they would not have access to enough current to be a problem when they fail. Information provided by a voltmeter is limited, little more than an idiot light.

adding to this:

The heating deal began on the poor stock alternator output capacity at iddle making unnecesarilly swing the needle back and forth. This is the ammount of load coming and going. This unnecesary load going throught the ammeter due the poor alt caused heat on shunt. Studs are pressed into the internal shunt. This copper shunt gets stretched with heat loosing the pressure between studs and shunt, then a failed conection increasing even more the resistence on ammeter. Hence the reason to get a good alt, saving the excess of unnecesary load running trhought it. If this was propperly addressed from factory back in the days, we never got worried about them decades later.


also:
Volts are a mirror reading of the load ( amperes ) and load is what makes work everything. So with a voltimeter you get a reference reading while with an ammeter get a straight reading.

We usually compare electricity with water flow, but I preffer this:

two guys pushing a car on a street apply some force on to move it. When getting the car into a driveway, you need more force to get it into the driveway.

the guys are volts, the force they apply ( each one ) is the amperes. What is requesting more to be moved is the car itself. So the device is what demands the load, but based on the provided voltage ( two guys ). The guys got some force limit, they can't give more than what they are able to, but STILL they are two guys. You can increase the volts to help ( one guy more ) but STILL the car will demand the same force ( amperes ) to be moved.

this is not a PERFECT example, but maybe easier to understand than the water flow.

This is why the voltage regulator is the lead on the alt output for amperage. There is no way to control the amperage from the source because amperage is never pushed but sucked by the devices, however increasing voltage alternator will be able to produce requested amperage. But what actually is needed to work is amperage based on a voltage rate

 

[72RoadrunnerGTX]

The heating deal began on the poor stock alternator output capacity at iddle making unnecesarilly swing the needle back and forth. This is the ammount of load coming and going. This unnecesary load going throught the ammeter due the poor alt caused heat on shunt. Studs are pressed into the internal shunt. This copper shunt gets stretched with heat loosing the pressure between studs and shunt, then a failed conection increasing even more the resistence on ammeter. Hence the reason to get a good alt, saving the excess of unnecesary load running trhought it. If this was propperly addressed from factory back in the days, we never got worried about them decades later.

Nacho, do I understand you are saying a healthy stock ammeter with good clean connections will generate heat while operating within its scale range, enough heat to mess with the metallurgy of the buss/shunt? Last I heard, metals expand when heated. I have to strongly disagree there, never saw that back then while wrenching on these cars at the dealers. A factory installed cluster/ammeter, with dry un-touched good connections and insulators and a generally healthy electrical system, lasted many trouble-free years with no sign of ammeter heat related problems (until the construction changed to plastics). While charge circuit bulkhead connections burned up regularly at a very early age. So much so, most repairs were still under warranty and or recall in some cases.

Again, nothing about automobile design of that time was ever intended to still be operating today. Factory alternator capacity (35-50 amps) was more than adequate for the then factory vehicle loads to last the then design life of these cars.

 

[Nacho-RT74]

Well still I think the stress added to the ammeter with the load going back and forth unnecesarilly due the poor stock alt rate it helped on premature failures. Any contact transition ( terminals, studs or whatever ) it is a potential resistence no matter if minimun hard to measure. Of course on earlier years will be hard to detect this failure, but mabe after 20 years could be easier

Then along the years extra accesories incorrectly added to the batt post increased exponentially this issue.

Just my opinion.

 

[Kozlow]

Aaand EVERY device, stock and additions installed on your car MUST be sourced from alt side, never from batt post ( with just minor exceptions ), because THIS will stress the ammeter too adding unnecesary loads there, aside get wrong readings. This has being a HUGE mistake made along the years on ammeter equipped cars, blaming then the "unsafe" ammeter feature, where maybe the unsafe feature on this maybe is behing the steering wheel.

So...this makes sense, and I can agree with all this.
Using a modified wiring set up with parallel wiring, retaining the amp meter,
where would someone install a large audio amplifier power lead too?

 

[72RoadrunnerGTX]

where would someone install a large audio amplifier power lead too?

See post #21, second picture for one example of Amplifier connections on the alternator side of the ammeter.

 

[Kozlow]

See post #21, second picture for one example of Amplifier connections on the alternator side of the ammeter.

If the amp was hooked up on alternator side of amp. gauge while the engine was running it would be fine, but if the amplifier was on but the engine wasn't running then the power draw would go thru the amp gauge and thru the wire from the amp gauge to batt.
Not saying that one would want to run the amplifier without the engine running, but if the engine was ever to stall with it on, then a possible 100+ amps would back feed thru the amp gauge and the small wire 14 gauge fusible link at the starter relay?
​

 

[Nacho-RT74]

yes, with engine off, the ammeter will read Discharge, which is true, you are getting discharged. So you are on the right reading

yes, after a discharge process when you get the engine running will get a charge reading as far the alternator is able to. Yes throught the 14 gauge fuse link ( or 16 on stock assembly ), HOWEVER, even having a thousand amps alternator STILL amperes can't be pushed in, the battery will just suck in what chemically is able to suck. You can't speed the chemical process into the batt more than its own capability, no matter the alternator output. However with a powerfull alt will guarantee a good average power recovery, without low and high peaks.

 

[Kozlow]

yes, with engine off, the ammeter will read Discharge, which is true, you are getting discharged. So you are on the right reading

yes, after a discharge process when you get the engine running will get a charge reading as far the alternator is able to. Yes throught the 14 gauge fuse link ( or 16 on stock assembly ), HOWEVER, even having a thousand amps alternator STILL amperes can't be pushed in, the battery will just suck in what chemically is able to suck. You can't speed the chemical process into the batt more than its own capability, no matter the alternator output.

Right... but what im asking is

With the engine off and the amplifier on, and in a discharge state, won't the high amp draw from the amplifier be too much and blow the 16 gauge fusible link ?

 

[Nacho-RT74]

Let's see. Dunno what you could consider a high amp amplifier for a car... unless you are calling for a competition autosound system????. Check the amplifier specs for the load requirements, but I don't think a regular use amplifier will draw more than 12-15 amps! And that could be for a constant sinusoidal 1Khz frequency emision.

A regular modern Stereo system ( 40 or 50 watts x 4 ) won't draw more than 5 amps.

blow the fuse link could take up to 50-60 amps, and thats just if stays on that rate, not for a peak

 

[rrTor-Red]

So, I have a 100amp alt and it's a 1-wire hookup with the internal regulator.

Why do you need a 100 amp alternator?

 

[Kozlow]

Let's see. Dunno what you could consider a high amp amplifier for a car... unless you are calling for a competition autosound system????. Check the amplifier specs for the load requirements, but I don't think a regular use amplifier will draw more than 12-15 amps! And that could be for a constant sinusoidal 1Khz frequency emision.

A regular modern Stereo system ( 40 or 50 watts x 4 ) won't draw more than 5 amps.

blow the fuse link could take up to 50-60 amps, and thats just if stays on that rate, not for a peak

Yes, 4 gauge wiring recommended with 80 amp fuse.

Maybe it would be better to run a second battery with a separate charge wire from the alternator?

 

[72RoadrunnerGTX]

Yes, 4 gauge wiring recommended with 80 amp fuse.

Maybe it would be better to run a second battery with a separate charge wire from the alternator?

Yes, very large or multiple amps would best be served with a separate battery, charging through a battery isolator.

 

[72RoadrunnerGTX]

Why do you need a 100 amp alternator?

Primarily to achieve a higher than stock low rpm output capacity, more overall load capacity at idle.

 

[Kozlow]

Yes, very large or multiple amps would best be served with a separate battery, charging through a battery isolator.

Battery isolator... good idea!