[tazdevil]

I have a Powermasater 75 amp single wire on my Demon. Good current at lower RPM's, and chrome finish is very classy. This unit has it's own regulator built onto the frame, is single groove as well. Highly recomended. Non chrome is available. No more external regulator, one fat wire to the battery. Mancini is one source.

 

[storm9c1]

I have a Powermasater 75 amp single wire on my Demon. Good current at lower RPM's, and chrome finish is very classy. This unit has it's own regulator built onto the frame, is single groove as well. Highly recomended. Non chrome is available. No more external regulator, one fat wire to the battery. Mancini is one source.

Yeah, thanks for the lead. I considered aftermarket, but I usually prefer to get off the shelve parts from local stores since if I get a DOA one or need one again later, there's a good chance I can get it quickly with minimal effort. I'm also not a big fan of single wire alternators. My experience with them is mixed -- they don't seem to regulate the voltage and charge as accurately, especially at lower RPMs.

I went ahead and ordered the 78A NAPA unit (13-2029 is the one with the lifetime warranty). It will look completely stock under the hood (which is what I want). It was under $70. Can't beat that.

 

[dana44]

You probably could have simply replaced the brushes for about $5. That's usually what happens to them anyway unless you have melted wires or burned out diodes, which is a little more complex to repair.

 

[storm9c1]

You probably could have simply replaced the brushes for about $5. That's usually what happens to them anyway unless you have melted wires or burned out diodes, which is a little more complex to repair.

I know, but I wanted to use this opportunity to replace the wrong dual groove alternator with a single groove one. Plus last time I replaced brushes on an alternator, I broke the keeper somehow and ended up needing a new one anyways. Why bother unless you have a factory original concourse alternator? I'll get a lifetime warranty with this new one along with new bearings and the rest of the mechanicals (which were of unknown age and condition from the previous owner anyways). Seems to be the best route in this case.

How do I test the voltage regulator? Mine has been replaced with a solid state version. With the engine running and measuring from each field terminal to ground, I was seeing battery voltage. Does that mean it's working or is there a better test? I just want to make sure my regulator is working OK too. And if not, then I will replace it at the same time and be done with it.

 

[dana44]

You have full gauges in the dash, the amp gauge should show dead center to plus side if it is working. At idle, turn on as many items as you can to see if the needle moves, and if it goes negative and you shut things off and it goes positive, it's working.

 

[storm9c1]

You have full gauges in the dash, the amp gauge should show dead center to plus side if it is working. At idle, turn on as many items as you can to see if the needle moves, and if it goes negative and you shut things off and it goes positive, it's working.

And this is exactly how I knew that the alternator was dead, well that and slowly dimming headlights and dash lights...LOL. It was doing all discharging and no charging at any RPM and at any load. Putting a meter on the back of the alternator (output stud) reveals only battery volts (12VDC or less as the battery discharges, engine running, at any RPM), no charging volts. It should be reading 14VDC, especially at higher RPMs. It's not.

But a dead alternator and a dead voltage regulator could cause this. I'm replacing the alternator regardless, so I guess I'll have to wait until I put it in to know for sure. If it still doesn't charge, then I'll replace the VR. But I was wondering if there was a way to proactively test the solid state VR module. I figured if I am getting voltage at the 2 field terminals, it's working, but just wanted to confirm...........

 

[dana44]

Best way to verify alternator is to, with the engine running, pull a battery cable off. If the engine instantly dies, alternator, bar none. A bad voltage regulator would keep running because the alternator would most likely overcharge, or it would just bypass the voltage regulator and keep running.

 

[storm9c1]

Best way to verify alternator is to, with the engine running, pull a battery cable off. If the engine instantly dies, alternator, bar none. A bad voltage regulator would keep running because the alternator would most likely overcharge, or it would just bypass the voltage regulator and keep running.

I'll try that.

But here is an interesting debate on doing that. Back around the year 2000, Sears made a "Security battery". I bought one. It was neat (but then suffered a safety recall later). It came with a remote. And when you armed the battery by pressing the remote, it was an anti-theft device. When you entered the car with it armed, the dome lights and accessories still worked, but if you tried to crank the car, it would start, run for a few seconds then die (if not disarmed) by completely disconnecting itself. There were no external mechanisms. It worked like a standard battery, no extra wires. So if the car died when the battery was disconnected (which my '95 Caprice did that had the battery installed), how does the alternator test you recommend actually work? I know in theory, the alternator should provide enough power to keep the car running, but an electrical engineer friend of mine told me that the "field windings" become "unstable" without a battery to smooth out the ripple in the system. Without the battery, the field eventually fails and the engine should stall, even with a good alternator. I've been reluctant to test this on cars in fear of blowing something up, but the Security Battery worked somehow! Furthermore, when I used to race, the emergency cutoff switch on most cars simply was in series with the battery. So I am confused and this always seems to be an area of debate.

Just to prove that security battery existed for those who never heard of it, here are some references of the release and then recall a few years later:

http://www.prnewswir...f-77348462.html
http://www.camaros.n...ead.php?t=43107

I had one, and it worked great for 6 or 7 years. I never acted on the recall and it died a normal worn out battery death. I never did scrap it, it's still sitting in my garage. Someday I'd like to take apart the security module and see how it worked.

But I am also curious about this "disconnecting the battery and running on the alternator only" debate because there are inconsistent facts about it. The Security Battery is one of them.

 

[dana44]

For as long as I can remember (several decades, let's say), this was and is the best way to test an alternator functioning. Now I wouldn't do this with any car with a computer and EFI system, just out of the state of the art electronics and all that garbage, but a carb'd, distributor'd, even electronic ignition'd engine, it is foolproof. Been proving bad alternators this way, let's say, since the early to mid 70s, OK?

 

[storm9c1]

For as long as I can remember (several decades, let's say), this was and is the best way to test an alternator functioning. Now I wouldn't do this with any car with a computer and EFI system, just out of the state of the art electronics and all that garbage, but a carb'd, distributor'd, even electronic ignition'd engine, it is foolproof. Been proving bad alternators this way, let's say, since the early to mid 70s, OK?

I got ya. I'm just engaging in a healthy debate. I've had this same debate with other car fanatics. The root of the debate is the inconsistency in data. I'm an engineer and have a scientific mind and like to prove why things behave instead of blindly accepting them. I appreciate your help.

 

[dana44]

I can accept that, and it is fair. It is about a thirty second check to start the engine, loosen the battery post and pull it. If it dies instantly, alternator, but if it keeps running, alternator and voltage regulator good. I did have one time a computer internal voltage regulator was bad (idiot light, not amp gauge), so it was an alternator change extra, but that was an exception, not a rule.

 

[Bob Lincoln]

dana is right, you can do this on older cars without computers, and it is very definitive. With a computer, you risk a voltage spike that will kill the computer, which makes it a very expensive diagnostic tool for cars newer than about the mid-80s.

 

[storm9c1]

dana is right, you can do this on older cars without computers, and it is very definitive. With a computer, you risk a voltage spike that will kill the computer, which makes it a very expensive diagnostic tool for cars newer than about the mid-80s.

OK, cool. Still doesn't explain how the aforementioned "Security Battery" worked. I used one myself and it did as it claimed. The car would shut down when tripped. And didn't blow up a mid-nineties era car with a sequential port FI computer. These batteries were mass produced and sold, supposedly worked for all cars. So I wonder how those actually worked. It's a good study.

 

[Bob Lincoln]

Sounds simple. It apparently had a transmitter in a key fob, and receiver in the battery. along with the disable circuit. It probably was a simple voltage comparator that cut off internal power when the voltage dropped to a certain level - either through unauthorized cranking or by leaving high-powered accessories like headlights on.

I would imagine that disconnecting the battery in this case would kill the car and therefore be an exception to the alternator test.

Pre-computer, a car would not die from running off a good alternator. Chrysler proved it in 1960, countering GM's claim that the alternator wasn't sufficient to power the vehicle. They disconnected the battery, locked the hood and drove it from Detroit to Chicago and back without shutting down.

 

[dana44]

Agree, sounded like there was a circuit inside the battery itself which would shut the power off itself. Sometimes recalls are for a reason. It may have been a self-grounding circuit which would shut the alternator down or something like that, no fob, no signal, ground the system out and make it shut down. Same thing with those little remote cars the cops can use to drive under a speeding car and somehow ground them out to kill them. No idea how that one works myself.

 

[storm9c1]

I would imagine that disconnecting the battery in this case would kill the car and therefore be an exception to the alternator test.

But curiosity tells me "why" or "how" did this work? Why is it an exception? If removing the battery from the circuit will not shut the car down, how did this special battery work? Back then, I bought one of these batteries (and still have it sitting dead on my garage floor, BTW) and It didn't have a "compatibility list". It just worked. I never used it in my Charger, but I did use it in a variety of other vehicles. And it worked on all my cars. And the way it worked was just by removing itself from the circuit when tripped. No different than unhooking the terminals.

I'm not debating whether we are right or wrong about running a car on an alternator with no battery, that is still dubious because some cars can and some cars can't. I just wish I understood this scientifically, because scientific principles say it should be reproducible in all instances. There shouldn't be exceptions. Especially with how simple some of these charging circuits are.

I did dana44's test, and my Charger died immediately. So that confirms that my alternator is bad. I'm replacing it. That much is certain. And thanks for that advice. I wish I knew how to test the voltage regulator correctly because I can also see the case where it could be bad and cause one to misdiagnose a bad alternator.

But this is a really interesting debate nonetheless.

 

[storm9c1]

OK, I have an update on this. I ended up going with the NAPA 213-2029 78A alternator. First one showed up DOA (actually had broken pieces inside the box). Second one took a week to arrive and worked fine out of the box (sans a slightly bent pulley, but I can live with that).

Upon removal of the old alternator, I noticed one diode was completely blown apart, and a second one was cracked. So that explains my no-charge condition. I installed the new alternator. Started the car. No charge (still!). So not only was my old alternator bad, so was my voltage regulator. My Charger came with an upgraded electronic voltage regulator and alternator (I believe these started in 1970) upgraded by the previous owner. So I tested the regulator by shorting the green wire at the regulator plug to ground (I think it's the outer pin from memory). First I tried it through a spare headlight bulb just in case I picked the wrong wire. When the headlight only lit dimly, I knew I had the right wire (and not straight 12V+ which would have been bad to short to ground). Upon removal of the bulb from the circuit, and touching it to ground, my voltage shot up to 16V and I could hear the engine struggle. I only pulsed it for a moment. That was all I needed to determine that the old regulator was bad and the new alternator was good. Perhaps the old regulator's death fried the old alternator or vice versa.

So the next adventure began. Naive me, Advance Auto is nearby. So I went there, and ordered their cheapo VR. Of course that didn't work out of the box. DOA. No voltage from the alternator. I read about these online and found out that the cheap ones usually don't work. So I returned that one. Next, I went to Autozone and they had a Duralast MADE IN THE USA version. Much more expensive ($27). Sounds good. I installed that one. But nope, it isn't right either. This one doesn't regulate correctly. At 3000 RPM, it's pushing 15.5V and my alternator belt starts squeeling. Bad news. I even ran a ground wire directly to the case of the regulator, knowing that if it doesn't see a good ground, it doesn't work properly. Still no go.

So this began my third adventure. I had enough with aftermarket parts. After searching eBay for a while, I found a seller (actually a Chrysler dealership) that was selling official Mopar restoration voltage regulators. I even found a proper date coded one (manufacture date 1969, which would have went into 1970 model year cars which is the closest year to my Charger). And guess what? It was slightly cheaper than the Autozone Duralast one! I ordered it. It arrived. I installed it, and it worked PERFECTLY. When it comes to these voltage regulators, use Mopar or no part. The original factory part number is 3438150. The current Mopar part number is 77R06286.

One caveat with the Mopar VR: you must scratch/sand/file off the paint down to bare metal at the bolt holes. The case must make a good ground for the VR to work properly. The black paint or powder coating they use is very thick and durable. Normally this is a good thing. But not for electrical contact.

 

[dana44]

Good deal. I have been coming to the same conclusion with all electronics and sensors, factory original or nothing for Mopars. I had the misfortune of having a cam sensor on my PT Cruiser that ended up costing about $800 is diagnostics, timing belt checking and a trip to the dealership to find out the material the sensor was made up allowed a voltage leak to the body and the computer would pick it up after a while as an intermittent miss on all cylinders and there wasn't anything wrong with it or anything else with the engine, factory cam sensor fixed the problem.

 

[storm9c1]

Good deal. I have been coming to the same conclusion with all electronics and sensors, factory original or nothing for Mopars. I had the misfortune of having a cam sensor on my PT Cruiser that ended up costing about $800 is diagnostics, timing belt checking and a trip to the dealership to find out the material the sensor was made up allowed a voltage leak to the body and the computer would pick it up after a while as an intermittent miss on all cylinders and there wasn't anything wrong with it or anything else with the engine, factory cam sensor fixed the problem.

It's not just Mopars. My LT1 Chevys don't like aftermarket parts either. I have to use factory sensors or else I have the same types of problems. How do these aftermarket parts suppliers stay in business? Nevermind...