30, 41, 46, 50 amp alternators? Yeah RIGHT

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TylerW

TylerW

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So, has anyone noticed the funny business Mopar used with their alternator ratings? Oh, I know there were supposed to be different ratings available on paper in different years, but I spent some time looking through parts books recently and found some interesting stuff. Let me clarify that I'm not a charging system expert or an alternator expert. Perhaps there is an unlisted component involved that changes the output of the alternator, but I'm not certain what that would be.

I looked at the 1965 through '69 parts books first. In 1965 and '66 there were two "common" alternators available...the "830" alternator which was a 30-amp unit, and the "850" alternator which was a 50-amp unit. The parts listings, including rotor, stataor, rectifiers and everything else appears to be identical. In '67 and '68, there were 3 alternators, the "537" 37-amp unit, the 850, and the "010" 60-amp unit. Now everything started to be more accurate...there were two different rotors, 3 different stators and two different rectifiers. That makes sense.

In '69 there were nearly a dozen part numbers that I didn't want to work through, so I skipped to 1972. The 8803, 8804 and 8806 are the 34, 41 and 50-amp units. Again, no difference in components. Skip to 1974, same deal. The first three alternators are even in the same column by now. So, are the parts books telling the techs to build them all back as 50-amp units if they had one fail, even if that's not what the car came with? Were they charging(ha ha, get it?) customers for a higher-output alternator even when they already had one?

I actually have two unrebuilt 1974 alternators on hand. One is 34-amp, one is a 50-amp. They look identical except for the tags.They both have the same green stator. Maybe there a difference, but the book says no.

Well just something I found curious but not surprising. Yes, there are more alternator applications than I mentioned.
 
The differences are internal, they used different diodes, windings and capacitors.
 
The following explanation relates to the 1974 parts catalog.
The 403, 404, 406 and 411 alternators were all serviced by the 3780588. The 34 and 41 amp alternators were replaced by the 50 amp alternator part # 3780588.
You couldn't buy the original 34 or 41 amp alternator or the component parts. Only the 50 amp was available as a replacement. All of the component parts listed were for the 50 amp: 3780588.
So to repeat ; 403,404,406 and 411 were replaced by the 3780588- 50 amp alternator and only the component parts for that alternator could be purchased.
Chrysler doesn't clearly explain this in the parts catalog.
 
There was probably a service bulletin that was put out to the parts departments. You have to remember that back then parts men were "real parts men" not computer jockeys that can't find there *** with both hands.
 
why don't you just take the 2 alternators (assuming they haven't ever been rebuilt) to a rebuild shop and ask them to test the output. When I realized the potential damage to the rest of the electrical system from high amp alternators (a potential fire from my 100 amp alternator 'improvement'), I started taking old alternators to a rebuild shop, having them find one with the correct output, and getting it rebuilt at that output. It amazed me how high the output from some of the parts store rebuilds were...
 
You can use a bigger alt [ higher amp rating ] in place of a smaller alt, but not the other way round. The penalty will be a very small increase in power to drive the bigger alt & probably a small weight penalty.

I suspect substituting bigger alts for smaller ones was Chrys way of reducing spare parts shelf inventory.
 
Diodes do not change the output. You forgot to include the Neice-Vinelle (spelling wrong) on police cars at 100 amp. Some alternators seem to have different outputs depending on year. After all this time so many parts have been mixed and matched that part numbers are not a guarantee of its output. Only spinning it up will tell. I have the correct alternator on my car not for it's output but only for it's part number.
 
Also let’s not forget… chrysler had many vendors for the same part. Each vendor probably had a guaranteed output. All the parts assembled the same. But one company stated theirs was a 37amp output and yet company B said theirs would do 50amps. (Not 50 all day long but marketing highlighted it could so that was it) At that moment in time, what was the actually amp requirements for the car. Other than towing a trailer the amp requirements were low. One speaker radio, lights and ignition and maybe a blower motor… that’s all.
And don’t even bring in rebuilders because they are using all Chinese made replacement parts now. That throws a whole different variant into the mix.
Syleng1
 
townsend said:
The following explanation relates to the 1974 parts catalog.
The 403, 404, 406 and 411 alternators were all serviced by the 3780588. The 34 and 41 amp alternators were replaced by the 50 amp alternator part # 3780588.
You couldn't buy the original 34 or 41 amp alternator or the component parts. Only the 50 amp was available as a replacement. All of the component parts listed were for the 50 amp: 3780588.
So to repeat ; 403,404,406 and 411 were replaced by the 3780588- 50 amp alternator and only the component parts for that alternator could be purchased.
Chrysler doesn't clearly explain this in the parts catalog.
Click to expand...
Thank you!
That confirms what I had posted previously as a possibility.

Syleng1 said:
Also let’s not forget… chrysler had many vendors for the same part. Each vendor probably had a guaranteed output. All the parts assembled the same. But one company stated theirs was a 37amp output and yet company B said theirs would do 50amps. (Not 50 all day long but marketing highlighted it could so that was it) At that moment in time, what was the actually amp requirements for the car. Other than towing a trailer the amp requirements were low. One speaker radio, lights and ignition and maybe a blower motor… that’s all.
And don’t even bring in rebuilders because they are using all Chinese made replacement parts now. That throws a whole different variant into the mix.
Syleng1
Click to expand...

I don't think that was a problem within Chrysler production. I do think it is a problem with aftermarket replacement alternators.
I suspect Chrysler had a method of rating their alternators whether it was made in house or not. Other than the few specialty Leece-Neville and Motorola alternators, I think there was only one vender for Chrysler used alternators of the '60s through mid '70s. Name escapes me right now - but the casting on those have their logo on it. In any event Chrysler controlled the specs both in terms of components and performance.

str12-340 said:
why don't you just take the 2 alternators (assuming they haven't ever been rebuilt) to a rebuild shop and ask them to test the output. When I realized the potential damage to the rest of the electrical system from high amp alternators (a potential fire from my 100 amp alternator 'improvement'), I started taking old alternators to a rebuild shop, having them find one with the correct output, and getting it rebuilt at that output. It amazed me how high the output from some of the parts store rebuilds were...
Click to expand...
Its great you found a shop willing to work with you. The two shops around here were not that helpful. One the guy was real grumpy and the other very nice. But both just tested if they 'worked'. The grumpy one had the setup to do an output vs. rpm test but he wouldn't even do a Chrysler FSM test (15 V with the equivalent of 1250 engine rpm).
 
Mattax said:
I do think it is a problem with aftermarket replacement alternators.
Click to expand...

See Speedtalk posts from 2014 by 'BC Johnny' where he was discussing the ways alternators produce power.
How Alternators are "Upgraded" - Don Terrill’s Speed-Talk

Mattax said:
Re: How Alternators are "Upgraded"
Post by BCjohnny » Sat Nov 22, 2014 6:34 am

<snip>
"Within a given frame size, simplistically, by increasing the cross sectional area of the conductor, in this case the stator windings, the amperage output is similarly increased. This can be done by increasing the number of turns of wire but more commonly by increasing the gauge with round section wire, or less commonly, going to 'flat-wound' large section wire (CAV, Denso etc). 'Re-wiring' the stator, for instance going from a star to delta wound arrangement, are other tricks manufacturers resort to, as is adding a 'tap' to star connected stators to create a four wire rectifier (~10%).

Upping the rotor magnetic field strength, again by increasing the number of turns, or increasing the field current, as Delco did with some european models by going from a 3amp to 7amp field, also give greater output to a lesser extent, as does reducing the rotor/stator air gap (obvious production limitations). Increasing the rotor diameter and 'slimming down' the stator width to maintain frame size, as Bosch did with certain 70/80amp K1s, is also an option.

Drawbacks..........As alternator efficiency is fairly constant across the better contemporary manufacturers, although in all cases goes down with machine temperature (alternators are most commonly rated 'hot'), increasing the output creates more 'waste' heat, which affects all components, but the rectifier to the greatest extent. Higher rated diodes, more efficient heatsinking, and cooling flow are required. In this last respect modern internal fan (IV) machines which cool from the inside out, as opposed to older front fan draw through types, are better capable of dealing with this. Or, as OE outputs grow, jacketed machines plumbed it into the cooling system are becoming more common. Increasing field strength means higher rated parts.

Also, again within a given frame size, increasing ultimate output is usually at the expense of lower speed output. Much like a highly tuned engine, the power curve is more peaky. The 'cut-in-speed' (CIS), when the machine starts charging, is often higher too."<end snip>
Click to expand...
 
The issue with swapping in a higher amp output alternator to some systems is the wiring in the system is not large enough to handle the increased amperage.


If your car is 100% stock not really a problem. Add on goodies and the 40 amp alt can not keep up but the max amperage is only 40 amps.

Swap in a 100 A alternator, now the alternator can provide 100 A in wires designed to only handle 40. Now you have a fire waiting to happen.

An alternator only provides as much current as it is being asked for up to its max. Kind of like the engine. It produces as much horsepower as is needed for the conditions up till it maxes out.
 
Chrysler built their own distributors, starters, alternators and other electrical parts at their Electrical Division on Shadeland Avenue in the city of Indianapolis.
By the 1970,s employment at the Shadeland Avenue Plant reached 3500. It closed in the mid 80's.
On another subject, Chrysler had many locally approved remanufacture vendors around the country. One company that supplied Chrysler with rebuilt engines in the 50's, 60's and 70's is still in business.
 
In reference to the early round back alternators, the simplest way to tell exactly what your remanufactured alternator actually is made of is throw the stater on a scale. It's weight would be different.
Once upon a time there was a shop called Mr. Alternator in G'ville SC that would rebuild your unit while you wait. Those variables are the main reason myself and many others would go there (sometimes pull the unit in his parking lot) and wait an hour or two rather than accept whatever the local part store or parts yard had available. His business took off. The "while you wait" thing might have lasted through the first year.
 
Great information. So it sounds like I need to find a used alternator testing machine, if one of those is capable of loading the alternator.
Curious though....why wouldn't Chrysler build just one "50-amp" alternator instead of going to the trouble of building different units such as the 34 and 41-amp versions? Oh well, guess we'll never really know how they were built without disassembling a bunch of unrebuilt units, which are dwindling.
 
TylerW said:
Great information. So it sounds like I need to find a used alternator testing machine, if one of those is capable of loading the alternator.
Curious though....why wouldn't Chrysler build just one "50-amp" alternator instead of going to the trouble of building different units such as the 34 and 41-amp versions? Oh well, guess we'll never really know how they were built without disassembling a bunch of unrebuilt units, which are dwindling.
Click to expand...
Yes. A machine. Specifically one that allows control of load, rpm and voltage would be really interesting.
However, depending on what you are trying to do, the most affordable/accessible testing can be done on the car.
The specs are in the service manuals. Different from the time the manuals were written is the ready availability of inductive clamps for measuring amperage.
Keep any test time to the mximum loads at a minumum. That's a downside of in-car testing.
 
RedFish said:
In reference to the early round back alternators, the simplest way to tell exactly what your remanufactured alternator actually is made of is throw the stater on a scale. It's weight would be different.
Click to expand...
Dang. Redfish, the scale is a great idea.
For the stators I had been trying look for visual clues (winding wire diameter, number of wires, color of coating)
At one time I went through a bunch of the FSM part numbers for stators and rotors to see which alternators they went in.
IIRC at least some of them had different rotors - at least by part number.

What I was doing last year was measuring field current draw and rotor resistance (slip ring to slip ring). It certainly revealed a big difference between original or at least correct rotors, and revised squareback and recent aftermarket rotors in general. Would not be surprised if it revealed some difference between various original/correct rotors for both roundback and squareback.

Both of those tests are pretty easy to do and don't require special equipment. Not sure why they scare a lot of guys off, but it shouldn't.
 
Interesting information on the alternator outputs. It begs the question for restoration. All the A bodies I see have yellow cap batteries but the lower amp units would have green caps. I wonder what is correct. Example my 71 Duster 340 has NO a/c and NO radio. Wouldn't it have green caps instead of yellow caps?
 
340wedge said:
Interesting information on the alternator outputs. It begs the question for restoration. All the A bodies I see have yellow cap batteries but the lower amp units would have green caps. I wonder what is correct. Example my 71 Duster 340 has NO a/c and NO radio. Wouldn't it have green caps instead of yellow caps?
Click to expand...
Can't answer about the cap colors, but whereas some instances we see higher rated alternators had to be paired with larger capacity batteries, that does not appear to be the case for '71. See the Salesman Pocket Guide and Dealer Data Books here

Some claims here that all '71 cars had green capped batteries (post 33).
www.forabodiesonly.com

Mopar battery dress up kits and cap color chart

Here's some slick kits to make your Parts store battery look like a original Mopar one. I bought a Everstart from Wal Mart that had smooth sides and top. The kits are shipped from Belgium so they will take a while to get there. Items for sale by weskcar | eBay UPDATE 1/22. they also have...
www.forabodiesonly.com www.forabodiesonly.com

??
 
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When I checked the output of my alternator it read 26 volts. Is that in the correct range as it seems a little high?
 
DVO said:
When I checked the output of my alternator it read 26 volts. Is that in the correct range as it seems a little high?
Click to expand...
Depends how you checked it.
 
I experienced a wiring fire in my '68 Cuda back in '76. My brother played the radio all day draining the battery. When I drove home, the charge indicator (ammeter) was nearly pegged until the bulkhead connector overheated and started an under-dash fire. Luckily I had a fire extinguisher and put it out and limped home. A new junkyard harness (luckily they were available in '76 saved the day, but I put a 6 gauge jumper wire from the alternator output post to the starter relay battery post to bypass the bulkhead connector. Never had a problem since then. Now I would put a 4 gauge jumper and fusible link just to be safe, but so far what I did in '76 worked.
I noticed that you can look into the alternator rotor and see the amount of windings used which give a clue of the output of the alternator. But that requires disassembly and having two different rotors to compare. I disn't see any markings on the rotor to identify the output they would produce.
I am switching to a square-back alternator for my current build hoping it is up to the task of handling halogen (Marchal Ampilux) headlights and dual cooling fans. The car is in a restoration shop and they just fired it up but I wasn't there to see how it all worked. Will update on this later.
 
TylerW said:
So, has anyone noticed the funny business Mopar used with their alternator ratings? Oh, I know there were supposed to be different ratings available on paper in different years, but I spent some time looking through parts books recently and found some interesting stuff. Let me clarify that I'm not a charging system expert or an alternator expert. Perhaps there is an unlisted component involved that changes the output of the alternator, but I'm not certain what that would be.

I looked at the 1965 through '69 parts books first. In 1965 and '66 there were two "common" alternators available...the "830" alternator which was a 30-amp unit, and the "850" alternator which was a 50-amp unit. The parts listings, including rotor, stataor, rectifiers and everything else appears to be identical. In '67 and '68, there were 3 alternators, the "537" 37-amp unit, the 850, and the "010" 60-amp unit. Now everything started to be more accurate...there were two different rotors, 3 different stators and two different rectifiers. That makes sense.

In '69 there were nearly a dozen part numbers that I didn't want to work through, so I skipped to 1972. The 8803, 8804 and 8806 are the 34, 41 and 50-amp units. Again, no difference in components. Skip to 1974, same deal. The first three alternators are even in the same column by now. So, are the parts books telling the techs to build them all back as 50-amp units if they had one fail, even if that's not what the car came with? Were they charging(ha ha, get it?) customers for a higher-output alternator even when they already had one?

I actually have two unrebuilt 1974 alternators on hand. One is 34-amp, one is a 50-amp. They look identical except for the tags.They both have the same green stator. Maybe there a difference, but the book says no.

Well just something I found curious but not surprising. Yes, there are more alternator applications than I mentioned.
Click to expand...
I do not know what the difference would be to change the amps output possible. The rotor contains the feild windings and to get a stronger magnetic field for more output should entail either heavier wires for more field current or more winds of wire. Similar for the stator, more winds for more current.
Now the rectifier is diodes that need to be big enough for the expected current they are expected to handle. The rectifier from a 100A alternator if physically the same size as one from a 30A alternator should
function fine. The rectifier from the 30A may not last in the 100A alternator.
Alternator output is a function of the rotor and stator windings. The regulator only controls field current to limit the output voltage. Apply full field current to an alternator and it can output 100+ volts.
Looking at the books, alternator outputs have steadily increased over the years to balance with the loads. The difference between a car with a 30A alternator and another with a 50A alternator was likely AC.
 
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