67 Barracuda Heavy Electric Load

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So with the car shut down and on the trickle charger for 30 min the battery is back up to 12.76.

The wire running from the alternator to the starter relay is 4 AWG.

I will take the alternator to a local auto store tomorrow to get the amperage.
 
You are posting some confusing info

At some point you said something like "the wiring is stock" and then said "it has been replaced."

Then you showed the AMMETER and mentioned the VOLTMETER. Has the ammeter been converted to a voltmeter? Have you eliminated the bulkhead connector? Otherwise, what you showed is a FACTORY AMMETER All the current in the car except the starter motor goes through the ammeter. It was never meant for such things as fans

IF YOU ARE running this kind of current through a STOCK LIKE/ STOCK TYPE wiring system WHICH STILL RETAINS the bulkhead connnector (or at least AMMETER WIRING) you are in over your head "for trouble."

"We need more (specific) info

HAS the bulkhead connector been eliminated?

IS the wiring non factory or not?

HAS the ammeter been eliminated, and is what we are seeing a voltmeter conversion?

THEN WE CAN get into "how large is" the wiring etc etc.

READ THIS concerning ammeter / bulkhead connector/ undersized wiring problems.

 
The wiring harness was replaced a few years ago. I said it is “factory” because my understanding is that the replacement wiring is “factory like”. I bought the car last summer and it has lots of upgrades and I am sketchy about many of the details. The Hanmetek meter I purchased on Amazon reads DC volts but it might also read amps - not sure about this.
 
The previous owner gave me the clutch fan that he removed. I would rather stick with the electric fan if possible. The new wiring still goes through the firewall with “factory like” connectors. See pic below.

IMG_5184.jpeg
 
The wiring harness was replaced a few years ago. I said it is “factory” because my understanding is that the replacement wiring is “factory like”. I bought the car last summer and it has lots of upgrades and I am sketchy about many of the details. The Hanmetek meter I purchased on Amazon reads DC volts but it might also read amps - not sure about this.
The issues I mentioned are the NUMBER ONE list you MUST address. You HAVE to figure out if the wiring is large enough or not, PERIOD. There is no possible way to get enough current through a bulkhead connector without melting terminals, etc. There is NO possible way to get that much current through a factory style ammeter.

Your low running voltage could very well be related to this if that is true.
 
The wiring harness was replaced a few years ago. I said it is “factory” because my understanding is that the replacement wiring is “factory like”. I bought the car last summer and it has lots of upgrades and I am sketchy about many of the details. The Hanmetek meter I purchased on Amazon reads DC volts but it might also read amps - not sure about this.
I would stick with Del (67Dart273), he is very knowledgeable in any and all things electrical.
 
It looks to me like the electric radiator fan is wired per the SPAL wiring instructions.
 
See pic below for the back side of the SPAL data sheet that includes the wiring diagram. I don’t think that the amperage goes through the firewall. Just the orange wire that signals the fan that the ignition is in the on position. I followed each of the wires and it looks to be wired exactly like the diagram.

IMG_5185.jpeg
 
Also the trickle charger has the battery up to 12.94 volts and the charger is still showing red (still charging).
 
See pic below for the back side of the SPAL data sheet that includes the wiring diagram. I don’t think that the amperage goes through the firewall. Just the orange wire that signals the fan that the ignition is in the on position. I followed each of the wires and it looks to be wired exactly like the diagram.

View attachment 1716186578
It would be nice to see the specs of the fan motor. Is it one or 2 fans?
 
One fan, approximately 14” with 5 blades and a 22” shroud. I have poked around on the internet looking for a match and have not found it yet.
 
Here is the voltage gage with electric radiator fan running with headlights off, then second pic is with electric radiator fan running and with headlights on.
No its not. That is amps to or from the battery IF AND ONLY IF the fan is wired to the alternator side of the engine side of the meter.
The link I provided in post 11 will illustrate this.
Is a standard digital multimeter like this capable of measuring the alternator amperage?
many, but not all, multimeters can meaure as much as 10 amperes current briefly. The one you have can not. It probably could be used with an inductive clamp that measures current. (see the second link in post 11 for info on one such clamp). The symbols on this meter's selection represent
1704166921024.png

Ohms (resistance) Voltage DC (Potential difference)
Continuity Voltage AC
The wiring harness was replaced a few years ago. I said it is “factory” because my understanding is that the replacement wiring is “factory like”. I bought the car last summer and it has lots of upgrades and I am sketchy about many of the details. The Hanmetek meter I purchased on Amazon reads DC volts but it might also read amps - not sure about this.
Lets start at the basics. Voltage is like pressure in a pipe. With everything off, the battery voltage is like the water pressure in your house with all the valves closed.
Current is electrons moving. Think of current in a river. With everything off, no current flows out of the battery. Turn something on like the lights, or the fans and current flows to those items and back to the battery's ground post.

When the engine is running, the alternator provides a higher voltage source of power then the battery. Measure voltage at the alternator output with the engine running and it should be around 14 Volts. This is why the alternator charges the battery and why power for running the car comes from the alternator when everything is working right.
Again, please look at the links provided in post 11.
The previous owner gave me the clutch fan that he removed. I would rather stick with the electric fan if possible. The new wiring still goes through the firewall with “factory like” connectors. See pic below.
Installing the clutch and mechanical fan is actually the simple answer. Adding electric fans, especially ones that may draw near 10 amps, really requires a rework of the factory wiring strategy. And the advantage of the electric fan is ? what ? for all this effort? A potential disadvantage is more restrictive airflow through the radiator than any of the factory options.
You don't have to believe me. Search through the heating and cooling forum and see the number of people who have struggled with the electric fans their shrouds. (Note the factory blades are 17 to 18" in diameter.) Can it be done? Of course. But it will likely be a project, not a plug and chug.
 
Pictures in post #12 show a relay for the fan so that load is not going through the stock wiring to run the fan. Post#31 shows a new reproduction M&H wiring harness at the bulkhead connector. (OP - M&H sells mostly reproduction stock harnesses but do offer an upgrade to the later transistorized voltage regulator which you have, and for factory electronic ignition - IMHO M&H is the best).

I see no indication that the ammeter has been converted to a Voltmeter, and the pictures of the gauge (post #14) seem to show the system charging before the fan and headlights are turned on (as desired) and then discharging when the headlights and fan are on ( as pointed out in post#22 by cosig). This results in the battery slowly draining down the more it runs. OP - when you start the engine with no accessories on, does the ALT needle pull toward the C (charge) and then slowly recover to just to the right of the middle mark slightly toward C? If so it should be connected as stock as an ammeter. If when first started the needle pulls toward D and then moves to the right, that would indicate the conversion to voltmeter - battery drawn down and then charged back up. Any chance the OP could film the gauge while starting the car and letting it run for a few minutes and post that?

Are the headlights something aftermarket that is pulling a big load through the regular headlight circuit in the stock wiring? If aftermarket are they, too, wired through a relay?

In any case I think the OP is headed in the right direction getting the alternator output tested and getting the battery tested, as a next step. I would bet the "high output alternator" is the factory AC alternator (though it has a single pulley), so 46 vs. 37 amp.

Final suggestion to the OP - I don't know why you are set on using the electric fan, but if it were my car I'd pitch it and go back to a solidly dependable factory fan with a clutch and a factory shroud. I know I will hear lots of blowback, but IMHO electric fans are great for a race car where every bit of parasitic horsepower loss is critical, but for a car you want to drive, not so much.
 
Thanks everyone for the replies. Here are pics of the voltage regulator, electric fan connector, electric fan, and alternator.

View attachment 1716186384





View attachment 1716186387

The voltage regulator picutred is for the system used in the 1970 and new A-bodies, not '67. It is called an isolated field alternator, and the alternator housing looks like a "revised squareback" which came out in the mid to late 70s.

Does anyone know how to identify the alternator p/n
If there is no manufacturer's label, then no. Many companies produce or rebuild alternators and they all have their own rating system.
The previous owner mentioned that the alternator was recently replaced and is high output. Any idea how to determine the specs/health of the alternator?
High output sometimes means high potential output at higher rpms at the expense of low rpm ability.
To actually know its potential, it has to be loaded to its maximum capacity at various rpms.
You might be able to find a shop to do that.
A couple examples of maximum output graphs here


What you could do just to know if its working is to measure voltage at the alternator's output stud with the engine running at idle and then at fast idle.
If you need to, shut the fan off while you are checking. The alternator at high idle should be producing power around 14 Volts regardless of whether the fan is on or the battery is charging.
If not, then it may be the alternator, or it may be the regulator, or how the regulator and alternator got wired up.
 
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See pic below for the back side of the SPAL data sheet that includes the wiring diagram. I don’t think that the amperage goes through the firewall. Just the orange wire that signals the fan that the ignition is in the on position. I followed each of the wires and it looks to be wired exactly like the diagram.

View attachment 1716186578
If the output of the alternator goes through the bulkhead and ammeter circuit, you still have the problem. When the car is running, EVERYTHING is pretty much powered by the alternator, not the battery. You must determine what mods have been made, what wiring upgrades have been made, etc

IF the ammeter is still an ammeter and not a voltmeter conversion, if it is factory, and if the alternator output goes through the bulkhead, you must change that to move forward. MUST
 
Here is one of my favorite simplified diagrams

This comes from the MAD article I linked earlier




amp-ga18.jpg


Now, you do NOT have to do the conversion as they did, and many advocate not, but I use this as a reference as to the how and why and the bad things about factory wiring

Follow the path.

We of course are talking here about bone stock factory wiring, but if the bulkhead is still used for the charge wire, and if the ammeter is still functioning, that is pretty much what you have. Starting at the alternator, the output (black wire) goes through the bulkhead connector.

RIGHT AWAY we have two problems. The factory charge wire is only no 10, and the bulkhead connector terminals are 1/4" flag/ spade terminals. IN HVAC they are used i electric furnaces for a nominal 20-25A current flow AND STILL FAIL sometimes.

From the bulkhead connector, the wire continues on to the AMMETER.

Where we have another two or three problems. the wire is still too small, the eyelet wire ends can fail, and the ammeter itself can fail and get hot. Then we turn it to RED, out of the ammeter, and at some point go BACK OUT the bulkhead connector, again through a 1/4" flag terminal, and back to the battery.

NONE OF THIS IS good for more than about 45-50A under heavy duty cycle conditions.
 
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If the output of the alternator goes through the bulkhead and ammeter circuit, you still have the problem. When the car is running, EVERYTHING is pretty much powered by the alternator, not the battery. You must determine what mods have been made, what wiring upgrades have been made, etc
Yes. Which is why he should look at the first link in post 11. Then he can see a drawing that illustrates what happens when electric fans are wired to the battery.
 
IF the ammeter is still an ammeter and not a voltmeter conversion, if it is factory, and if the alternator output goes through the bulkhead, you must change that to move forward. MUST
Funny how so many of the A-bodies on this site, including all 3 of my 70 Darts have made it successfully through over 50 years of use using the factory designed system AS LONG AS THE COMPONENTS ARE KEPT UP IN EXCELLENT CONDITION AND ARE NOT OVERLOADED WITH ADD ONS without bypassing the ammeter, the bulkhead connector...

The op apparently has a new reproduction factory (M&H) wiring harness. I think he needs to address the potential issues of add on electrical stuff and the function of the major components in the system.
 
Funny how so many of the A-bodies on this site, including all 3 of my 70 Darts have made it successfully through over 50 years of use using the factory designed system AS LONG AS THE COMPONENTS ARE KEPT UP IN EXCELLENT CONDITION AND ARE NOT OVERLOADED WITH ADD ONS without bypassing the ammeter, the bulkhead connector...

The op apparently has a new reproduction factory (M&H) wiring harness. I think he needs to address the potential issues of add on electrical stuff and the function of the major components in the system.
Most of them did not have large alternators, either, and some of the big ones had the factory bypass, known as the Police/ Fleet / Taxi wiring.

My 70 440-6 RR managed to "eat" the bulkhead terminals way way back about 1973 or so. Of course Al Gore had not invented the internet, yet, so I drilled out the wire holes in the connector and doubled up some larger gauge wire and fed through there. I also SOLDERED THE STUD CONNECTIONS in the ammeter, (to the shunt) which very interestingly, is documented by someone else in "today's" generation.

I've seen at least a dozen pickups with melted ammeters which had had such things as driving lights and or winches added. Another "biggie" was snow plow hoists, which were operated by large electric motors.
 
I did mention this in post 8 and 9. Stock wiring must be addressed . Can the VR be bypassed to see if the Alt will ramp higher as just a very quick test? Not sure how to do this but thought I read it here before? And as stated check voltage at Alt. should 14V or higher?

67Dart273 will definitely steer you right.​

 
Well I finished my egg, this morning. I see that I forgot to mention "the easy way" to bypass the problem.

Crackedback sells a little kit

So what you do is this:

1...DISCONNECT battery ground!!!

2...Disconnect the bulkhead connector plug containing the large black/ large red ammeter wires and closely inspect the terminals in both halves of the connectors for damage. Repair that as necessary
3....Unbolt the ammeter terminals and either bolt both ammeter wires to one stud on the ammeter, or use a separate bolt to splice them, then tape. (Consider adding a voltmeter)

4....Install Crackedbacks bypass kit or make your own. You want BIG wire for a big alternator and oversized from there if it is a "one wire" unit. This goes direct from the alternator output stud to a good solid path to the battery +. Either the starter relay "big stud" (But only if the supply to the stud is also large enough) otherwise devise a terminal junction etc to tie into the battery. On an alternator that big you probably should be using at least no4 wire OR LARGER IT MUST BE circuit breaker or fused in that path, near the battery

HOW THIS works, basically

First, this removes all the charge current going to the battery from the wiring into/ out of the passenger compartment. The old red and black ammeter wires are not effectively in parallel (makes them larger) to become the feed into the car for those accessories.

The charge current obviously now goes direct from the alternator to the battery.

If your heavy loads are properly connected, they will not be going through the bulkhead at all. They will come off the alternator / battery under the hood

THEN if the charge voltage is still low, you/ we can address that.
 
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