Round back to square back alt

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That is a 1/4" diameter of twisted copper strands under the insulation. So how are these small wires holding up?
90+ percent of the time you're only drawing maybe 10 amps max through that cir and maybe 20 while charging a very dead battery for example.



The wires will get warm but not fry, AS LONG AS EVERYTHING IS IN GOOD WORKING ORDER!
 
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My electrician looked at the 12V wire to the alternator and was shocked how small the factory wire is. He said that size wire is good for 20 amps max. So I Googled it and AWG (American Wire Gauge) ratings and charts show a 60 amp current should use a #6 gauge wire. That is a 1/4" diameter of twisted copper strands under the insulation. So how are these small wires holding up?
Google is wrong.
Go look at a section of residential wiring for outlets and a 20 amp cb or fuse and tell me if it is 1/4" in diameter solid copper. What's the AWG listed on the insulation? (assuming its NM) Granted this is AC but just to give some perspective on on how far off 1/4" diameter is.
Look at the factory cable sizes for the big ole starters. Those starters draw well over 100 amps (the in spec draw is in the shap manual).

To figure an appropriate wire gage one needs to know the length of the run, the high temperatures, and then one more variable such as how much loss in voltage is going to be acceptable. Several wire manufacturers and retailers have on-line tables and calculators. I think Blue-sea is one of them.
They will be in AWG because these are for marine use. SAE wire gage is pretty much limited to automotive applications.

Here's a couple but the marine I think is better but you'll have to search for that one.
There's a few wire size tables and calculators on-line.
Engine compartment runs at higher temperature, so voltage drops increase.
SAE gages have lower carrying capacity than AWG (Marine wire uses AWG sizing)
WireSizer User Guide
Wire Size Calculator

NAPA Premium+ 2132009 alternator rated 45-50 amps
NAPA Proformer VR38SB voltage regulator
Be interesting to know if the "45-50" rated alternator has a lower field current draw than the "60" amp
 
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90+ percent of the time you're only drawing maybe 10 amps max through that cir and maybe 20 while charging a very dead battery for example.



The wires will get warm but not fry, AS LONG AS EVERYTHING IS IN GOOD WORKING ORDER!
Alternator needs to supply as much as 25-30 amps when the lights are on, with the heater fan, and wipers going.* Battery charging would add to that. Its why I let the battery recharge during warm up with those things off. Don't need them on anyway while oil pressure is building and the engine warming up.
The 1/4" push on terminals are the weakest point in the flow path.

*See measurements posted earlier. 65 dart will be less since it has no side markers and the front parking lights are off with the headlights on.
 
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Gents, Getting a lot of useful if not similar opinions on that circuit's demands. Mattax, I bookmarked those calculator links :)
1) Could you post a screen shot of the calculator populated with the appropriate variables for that circuit? The larger battery wire to the alternator. We are talking 1965 Dodge Dart, 273 cu. in., no AC., all other stock accessories on, even stop lamps and then your suggestion for a wire diameter, not that I will change mine. Thanks!
2) Yes, I want to measure this particular alt's amperage at 2000 rpms to see if it really 45 amps max. Saw online that an Amp Clamp tester can do this over that same wire.
3) Should one put say a 30A inline fuse on the wire right off the alternator?
CKG
 
The "battery" terminal wire is from the alternator.
I dont have the 65 Dart FSM open right now but if its 12 SAE then this will be close.
Might have been SAE 10 gage. Only the heavy duty options got 8 gage.
1741544247574.png


I don't think there is more the 7' from the alternator to the main splice. So maybe 4-5' in the engine bay.
30 amps is a nice round number that should cover everything on plus a few amps recharging or for brake lights.
3% Voltage drop seems to the standard.
One wire is not fully true. At some point it gets bundled in with some otehr wires but thye are not carrying much current.

The '65 cars have a ring terminal connection at the firewall. Theyt should be more secure and more copper mass, so less likely to heat up than the push ons (Packard 56/58). But they are exposed to heat and moisture. We've seen examples where they do get melted. Nothing is 100% perfect.

I don't know the temperature rating of the OEM SAE engine compartment wire. Automotive primary insulation wire is usually lower rated - fine in the rest of the car.



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Measuring max current in the alternator output wire.
Personally I would not stress the wire and terminals like that.
My interest would be in how your alternator compares to factory spec alternators. That's a test at 1250 rpm, controlling the voltage to 15 V. It can be measured at the load (carbon pile) attached to the battery, or at the alternator output. When measured at the battery, the spec excludes power going to the ignition and field.
Another useful measurement that can be done with the clamp meter is to bring the rpm to 1250, and then measure output V and current with various accessories on, such as heater fan and lights, etc. If the Voltage stays above 14 and the ammeter shows the battery isn't discharging, then the alternator is capabale of handling the car's needs.
You can also see what the alternator can produce at slow idle.

All that said, my comment earlier was about field circuit draw, not output. Its supposed to be 2-3 amps.
 
The "battery" terminal wire is from the alternator.
I dont have the 65 Dart FSM open right now but if its 12 SAE then this will be close.
Might have been SAE 10 gage. Only the heavy duty options got 8 gage.
View attachment 1716376078

I don't think there is more the 7' from the alternator to the main splice. So maybe 4-5' in the engine bay.
30 amps is a nice round number that should cover everything on plus a few amps recharging or for brake lights.
3% Voltage drop seems to the standard.
One wire is not fully true. At some point it gets bundled in with some otehr wires but thye are not carrying much current.

The '65 cars have a ring terminal connection at the firewall. Theyt should be more secure and more copper mass, so less likely to heat up than the push ons (Packard 56/58). But they are exposed to heat and moisture. We've seen examples where they do get melted. Nothing is 100% perfect.

I don't know the temperature rating of the OEM SAE engine compartment wire. Automotive primary insulation wire is usually lower rated - fine in the rest of the car.



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Measuring max current in the alternator output wire.
Personally I would not stress the wire and terminals like that.
My interest would be in how your alternator compares to factory spec alternators. That's a test at 1250 rpm, controlling the voltage to 15 V. It can be measured at the load (carbon pile) attached to the battery, or at the alternator output. When measured at the battery, the spec excludes power going to the ignition and field.
Another useful measurement that can be done with the clamp meter is to bring the rpm to 1250, and then measure output V and current with various accessories on, such as heater fan and lights, etc. If the Voltage stays above 14 and the ammeter shows the battery isn't discharging, then the alternator is capabale of handling the car's needs.
You can also see what the alternator can produce at slow idle.

All that said, my comment earlier was about field circuit draw, not output. Its supposed to byes e 2-3 amps.
Thanks for the lessons and I really appreciate you providing that screenshot. My car has a 12 Gauge wire there. You have proven the stock wire is adequate if in good shape with all the variables applied so I can rest easy.
But why would Littlefuse inline fuse holders use a 10 gauge wire for a 30 amp fuse and a 12 gauge wire for a 20 amp fuse? I am thinking Chrysler should have used a 10 gauge at a minimum.

I hope to get my alternator output tested then I will share results.

Littlefuse.jpg
 
Let me give you some comparison. When I was working at the power chair manufacturing joint, the main thrust of my job became mostly building the drive modules, aka, the brains of the chairs. This is like a pair of huge battery powered drills. In other words reverse capability and speed control for two motors. These were very big PM motors which are either belt or chain drive to the tires.

So when I got modules done, both the super and I did what were called "bench tests" to check them out, then they went downstairs and installed on a "test chair"--a beat up very used chair, and we went out (in better weather) and did certain tests to stress and prove the modules.

Part of the test was a stall test, both reverse and forward. I used to roll the char right up against the building, so the footrests were touching the building, and run the joystick "firewalled" for several seconds. We had an ammeter on the chair to measure overall system amperage. The current drawn by the module just get it to operate was minimal, maybe a couple of amps. When you firewalled the thing at stall it would pull MORE THAN TWO HUNDRED AMPS total draw.

This is with a huge LiFePO4 24V battery. We also built a few 48V chairs, which were just plain scary. They would wheelie from a dead stop and would do close to 17mph. I DID NOT like testing them!!

So what? Here is what. The motors are fed WITH NO. TEN WIRE!!!! ONE HUNDRED amps through no.10!!!

The photo of the red wire shows part of the power wiring from the battery. There are two pairs of no10. The photo with the white and the blue are one set of motor wires. This goes to what is called an "H bridge" and each leg consists of the mosfets you can see mounted along the edges of the case. Those buss bars soldered into the pc board requires a big 'ol 250W American Beauty iron, and to solder the no10 wires to them, I'd flux them, get the iron down in there near vertically, with my elbow on the table for stability, heat it up some until it started to flow, but you could not get the tip in far enough to create good flow. So after the solder melted some, I'd drip a bit more flux on, then grab my Metcal with my left hand and add it into the mix. Believe it or not, in 4 years and hundreds of boards, I never screwed one up

IMG_0053cs2.JPG


IMG_0053cs.JPG


IMG_0052cs2.JPG


IMG_0042cs.JPG
 
my son an i built a "drift trike" using a chinese Tuk Tuk motor ( BLDC with reduction gearing designed to shift 1/4 tonne at 15 mph) and a similar controller.
our battery was a bunch of korean pouch batteries that look like A5 paper. we built a 200 amp (peak output, 100 amp continuous) 48 monster battery pack that melted the screw driver we were using to bolt it together, we used the wire that came with the controller pack. i thought it was too small. It does get a bit hot.....!
Li-ion cells (3.7V 20Ahr) for Powerwall, Solar bank,UPS,Ebike,Electric car etc. | eBay
these batteries kick a considerable amount of ***

similar wire size to your wire.

with nylon tyres (nylon gas pipe over the slicks) one good drift trike.......! yes we had some fun....
with karting tyres, rubber karting slicks in other words, you could stand the thing on its rear wheels if you were not careful.

it sacred us both, so we put it up the back of the shed and only talk about it in hushed voices....

that thing could easily take a hand off with its chain drive... after snapping its motorcycle sized chain, we treat it with respect..

i now pay a bit of attention to wire size but also wire size in relation to the type of connector and the space available for that connector and its crimp.... do not want to short out a lithium battery and have an explosion

Dave
 
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I can only speculate why Chrysler made the decision to use 12 gage wire. Presumably its a balance between ease of assembly, costs of materials, and acceptable performance. For example on the factory diagrams of this era we see the standard field wire for A-bdies was 18 gage vs 16 ga for B-bodies. Why? Was it because the wire run was shorter? Or perceived lower needs ? or just because they could get away with it to save weight and money on the smaller cars?

One thing I always like to point out is the headlights are a relatively big load, and can be running for hours. Additionally almost any replacement headlight from the last 30 years draws more power than the original 6012 sealed beams. Installing a relay circuit for the headlights not only gets power to the lamps with higher voltage, it means that alternator output wire never will see that electric load.

Alternator output vs input.
Field current draw off or on the vehicle. Post #9

Some info on alternator output measurements

Pulley ratio as well as the stator and rotor windings can really effect what can produced when the engine is idling at 500 or 600 rpm.
 
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Let me give you some comparison. When I was working at the power chair manufacturing joint, the main thrust of my job became mostly building the drive modules, aka, the brains of the chairs. This is like a pair of huge battery powered drills. In other words reverse capability and speed control for two motors. These were very big PM motors which are either belt or chain drive to the tires.

So when I got modules done, both the super and I did what were called "bench tests" to check them out, then they went downstairs and installed on a "test chair"--a beat up very used chair, and we went out (in better weather) and did certain tests to stress and prove the modules.

Part of the test was a stall test, both reverse and forward. I used to roll the char right up against the building, so the footrests were touching the building, and run the joystick "firewalled" for several seconds. We had an ammeter on the chair to measure overall system amperage. The current drawn by the module just get it to operate was minimal, maybe a couple of amps. When you firewalled the thing at stall it would pull MORE THAN TWO HUNDRED AMPS total draw.

This is with a huge LiFePO4 24V battery. We also built a few 48V chairs, which were just plain scary. They would wheelie from a dead stop and would do close to 17mph. I DID NOT like testing them!!

So what? Here is what. The motors are fed WITH NO. TEN WIRE!!!! ONE HUNDRED amps through no.10!!!

The photo of the red wire shows part of the power wiring from the battery. There are two pairs of no10. The photo with the white and the blue are one set of motor wires. This goes to what is called an "H bridge" and each leg consists of the mosfets you can see mounted along the edges of the case. Those buss bars soldered into the pc board requires a big 'ol 250W American Beauty iron, and to solder the no10 wires to them, I'd flux them, get the iron down in there near vertically, with my elbow on the table for stability, heat it up some until it started to flow, but you could not get the tip in far enough to create good flow. So after the solder melted some, I'd drip a bit more flux on, then grab my Metcal with my left hand and add it into the mix. Believe it or not, in 4 years and hundreds of boards, I never screwed one up

View attachment 1716376347

View attachment 1716376348

View attachment 1716376349

View attachment 1716376350
You have great soldering skills!
 
Remember, too that the earlier cars were just a very few years after everybody had generators, and VERY few of those were capable of over 25 or maybe 30A. There were no huge stereos, yet, and so on. The first factory alternators were in the mid 30's range.

Any of you who are not old enough to have experienced "generator" living, have miss out on, well, I'm happy they are GONE!!
 
I've said this before. The BIGGEST issue with the failures in the Mopar system is

1...the terminals used in the bulkhead connector for the ammeter, which were never designed for more than 20-25A. These same type of flag/ spade push on terminals were used in my days of HVAC. I used to service a fair number of heat pumps, and the usual norm for an air handler/ auxiliary heat is simply an electric furnace. The usual elements are fairly standard at nominal 5KW so apporox. 20A draw at 240V (nominal 4800W) AND THEY STILL FAILED sometimes at that level.

2...The ammeter construction, varies with model. On my 70RR the cluster housing was plastic, so ANY loosening of the nuts/ studs resulting in more softening of the plastic and more looseness. OF COURSE it failed!!! The only way to fix that and keep the ammeter is to silver braze the studs to the shunt, and then make absolutely certain that the studs and nuts are "locked" to good quality connections with the eyelet wire ends.

3...And I've said THIS before. Ma knew FULL WELL about the problem, as even by 70-ish, some of the big boats had external shunt ammeter circuits, as well as optional wiring (fleet-police-taxi) which at least partially bypassed the bulkhead problem.
 
Any of you who are not old enough to have experienced "generator" living, have miss out on, well, I'm happy they are GONE!!
I got a good shock off of a generator winding while polarizing it. everyone said I was crazy BUT it did happen. it felt like a spark plug hit.
 
I got a good shock off of a generator winding while polarizing it. everyone said I was crazy BUT it did happen. it felt like a spark plug hit.
Of course you did. It's called "inductive kick" and is similar to the shock you get of a lawn mower magneto grounding lead, or the transistor of the Mopar ECU--which is connected to the NEG of the coil primary. What happens is when you have ANY electromagnet type device, such as a relay coil, solenoid, transformer, ignition coil, etc, and you power it--even with say, an analog multimeter with the old 1 1/2V battery for the low ohms scale---the current flow will build a magnetic field, and when you disconnect (flash) the field collapses and develops a spike that you FEEL

This is why modern relays and circuits use a spike diode--because modern solid state switching circuits are prone to failure from the switching spike.

I've --in the old days when I was young, and before I joined the Navy, --gotten a real surprise when checking out old TV tube type power transformers with an ohmeter. "Not thinking" holding the meter leads against the transformer leads with my fingers LOL
 
Thanks for all the posts. I think I need this dumbed down.

My 66 bcuda currently isn't running and I am doing the alternator and some wiring while I'm doing it. Do I got a high output alternator, I removed the amp meter and it will get a volt meter instead. I plan to remove the wire that feed the ampmeter through the firewall and that fire hazard. And the fusable link is now a breaker.

I plan on using a higher gauge wire for the alternator power. But now I'm looking at wiring harnesses, do I need electronic ignition? Are their other components I haven't realized I need to replace with this electrical update? My goal is to bring some of the functions of a modern car with minimal updates that change the feel of the original vehicle.

Those additions, Hidden Bluetooth stereo with amps, electric fuel pump, adding the rear defrost fan option, hazard lights that mine doesn't not have, and with some luck a back up camera with a hidden screen that I got mounted in the flip down ash tray.

I'm currently looking at wiring kits, particularly for the engine compartment but like the idea of keeping the original bulkhead connector and running heavy gauge wire to the fuse box separately. Has anyone got any recommendations with that, or a good modern fuse box with added circuits that will mount cleanly into the original kick panel area?
 
Keep in mind that the bulkhead and many other connectors are only for assembly line work. You can delete them if you are reworking the wiring.
 
Hello all,

Thank you as always for the advice, experience, and suggestions. I am busy and slow to get this work done, so plenty of time for research and to forget what I've done between projects. As such I am considering the M&H engine harness sold by year one but here are the insights from there tech.

"
The main difference between the original harness we sell and the updated one, is adding the stock electronic ignition system and the dual field alternator that would be found on a 1972 Barracuda. Both harnesses use the same 10 gauge wire to the alternator. Based on your description, you will want to purchase the original harnesses for 1966. Now, there are some details you need to be aware of when modifying the harnesses. If you are eliminating the ammeter and possibly changing to the volt meter, take the large red and large black wires that would normally go to the ammeter and move them to a threaded stud junction block. Neither of these circuits will be used for a volt meter. If you remove the original alternator circuit in the engine compartment and leave just the battery circuit with the fusible link going through the bulkhead, it could cause extra stress at the bulkhead and result in heat that could melt the connector at the firewall. In addition, the black wire coming from the alternator does not go directly to the ammeter, but rather goes to a splice to feed other circuits including the ammeter. It is best to keep the black wire going to the alternator.

Next you will want to take some precautions when using a high output alternator.
  • Use the black wire as supplied in the harness to attach to the threaded stud
  • Attach an additional 10 gauge wire from the alternator threaded stud to the starter (will balance the charging system and take away added load at the bulkhead)"
And 2nd email:

"The engine/light harness includes most if not all of the under dash wiring. Counting all 3 rectangle connectors that go to the bulkhead correct?
Answer: This harness takes care of the wiring in the engine compartment. It is the separate dash harness that supplies most of the wiring under the dash.



-Is the Alternator wire in this new wiring been bulked up to like 10 gauge?
Answer: No. It is factory spec at 12 gauge.



-does the bulked up Alternator wire still go through the bulkhead as a single connector? I have overheating concerns based on ORM heat issues.
Answer: The main alternator wire black still goes to a single cavity on the bulkhead connector. With concerns about overheating the bulkhead we can suggest two alternatives.

1. Add an additional 12 gauge wire from the back of the alternator to either the starter relay or all the way to the starter.

2. Reroute the black alternator wire around the bulkhead and through the firewall with a new hole next to the bulkhead that includes a grommet to route the alternator wire. You may want to also reroute the main power wire with fusible link through the same hole. To still allow the connections to separate, use ring terminals and junction blocks. Alternator (R6) and battery (A1) circuits will need to be extended either in the engine compartment or under the dash. Call us for more details if you choose to proceed with this option.



-If not in the bulkhead connector, does the wire from the alternator to battery through the firewall differently?
Answer: No.



-does this still use a fusible link?
Answer:Yes, on the main battery circuit (A1)."
 
Has anyone tried to make their own wires harness and is so, have an idea on lengths? Im considering making my own but would prefer to make it in advance. This way it could have some heavier wire modifications.

Thank in advance
 
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