Charging system only reading 11 volts

Reece Stephens

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I have a 67 Chrysler Newport, I recently replaced the alternator with an OEM 55 amp alternator, and voltage regulator but it's only reading 11 volts. I've checked all my grounds, and I don't appear to have any parasitic draws on the battery. It slowly gets weaker and after about a week of being driven it'll kill an 850 CCA battery. This is my second replacement alternator, and I've checked most of my wiring off the positive cable and it seems to be good without a bunch of corrosion. What am I missing here?
 
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Chrome58

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Is it reading 11 volts at the battery or at the alternator's output?
 

halifaxhops

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Bench check the VR also, if it is set wrong you can get 11 volts also. Think your is mechanical, the FSM should have the procedures to adjust it.
 

CBODY67

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Do check the battery terminals, if not already having done that. Even if they might look good, there can be a thin layer of accumulation between the post and cable terminal, cleaning those items with a wire brush or similar. That thin layer of accumulation can decrease system amps output about 10+%, by observation. Get a full-system, in the car, charging system check done and go from there.

Just some thoughts,
CBODY67
 

Reece Stephens

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Do check the battery terminals, if not already having done that. Even if they might look good, there can be a thin layer of accumulation between the post and cable terminal, cleaning those items with a wire brush or similar. That thin layer of accumulation can decrease system amps output about 10+%, by observation. Get a full-system, in the car, charging system check done and go from there.

Just some thoughts,
CBODY67
It's a brand new battery and the terminals are also clean
 

SuperDave

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Is that 11 volts with the engine off - key on, or motor running at idle? Are there any aftermarket accessories, such as electric fans, electric fuel pump, high powered stereo with amplifiers, aftermarket ignition system, fuel injection, etc. attached to the vehicle? Where are you "measuring" your voltage from, at the battery, the alternator, or an aftermarket gauge wired into the dash?

Add-ons can suck a battery quick if the alternator isn't up to the task. I have most of the accessories listed above and had to go with a 130 amp alternator for mine. With the key on - motor off, it's 11 volts normally. Running down the road at 80mph/3k on the tach it pushes almost 16 (borderline overvolt).

2021-06-02.jpg


Have you bypassed the ammeter yet? Is the wiring factory original? Those bulkhead connectors were a weak link and can cause issues, melt, even create an electrical fire, especially with high draw add-ons installed. Also, have you run a wire from the alternator post directly to the battery yet? This provides a direct link around the in dash ammeter to charge the battery, it may render the ammeter useless but charge up the battery directly with priority. Go heavy gauge if you haven't, I went with a #2 gauge battery cable on mine.

2021-06-02-1.jpg
 
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Reece Stephens

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11 volts with the engine off - key on, or motor running at idle? Are there any aftermarket accessories, such as electric fans, electric fuel pump, high powered stereo with amplifiers, aftermarket ignition system, fuel injection, etc. attached to the vehicle? Where are you "measuring" your voltage from, at the battery, the alternator, or an aftermarket gauge wired into the dash?

Add-ons can suck a battery quick if the alternator isn't up to the task. I have most of the accessories listed above and had to go with a 130 amp alternator for mine. With the key on - motor off, it's 11 volts normally. Running down the road at 80mph/3k on the tach it pushes almost 16 (borderline overvolt).

Have you bypassed the ammeter yet? Is the wiring factory original? Those bulkhead connectors were a weak link and can cause issues, melt, even create an electrical fire, especially with high draw add-ons installed. Also, have you run a wire from the alternator post directly to the battery yet? This provides a direct link around the in dash ammeter to charge the battery, it may render the ammeter useless but charge up the battery directly with priority. Go heavy gauge if you haven't, I went with a #2 gauge battery cable on mine.

I bypassed the ammeter over a year ago. Aside from a pair of LED headlights I don't have anything that would drain my battery. It doesn't matter if the car is on or running it read 11 volts, and if I turn on the running lights and the heater, it goes as low as 9.5 volts. Like I said, I don't have very much hooked up to the battery beyond the pair of LED high beams, and when I turn them on the gauge does not move.
 
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Reece Stephens

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Is it reading 11 volts at the battery or at the alternator's output?

I have the gauge wired in at the fuse panel running on a keyed power circuit. Regardless of whether it's at the alternator output or battery it shouldn't ever dip below 12 volts though.
 

halifaxhops

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No matter where the reading comes from it is to low. Remember the VR regulates everything including the output of the alt just trying to help out.
 

SuperDave

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I have a volt gauge wired into the car at the fuse panel, I'm not using a handheld reader or a

Try to see if you're getting a voltage drop between the battery and fuse box by using a handheld multimeter on each. Those 50 year old bulkhead connectors may have dirt or corrosion in them impeding the current and give a false reading at the fuse box.

If it all checks out, try another voltage regulator from a different manufacturer.
 

Reece Stephens

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Try to see if you're getting a voltage drop between the battery and fuse box by using a handheld multimeter on each. Those 50 year old bulkhead connectors may have dirt or corrosion in them impeding the current and give a false reading at the fuse box.

If it all checks out, try another voltage regulator from a different manufacturer.
I actually have an aftermarket voltage regulator in, and it reads exactly the same as the original one that was in the car. I haven't had the bulkhead connector apart yet so I may try cleaning that and putting dielectric grease on it
 

SuperDave

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Maybe you got a bad alternator. It does happen, especially since many vendors are outsourcing stuff from overseas nowadays. I have gotten a LOT of stuff labeled "Made in China" that was bad out of the box.

Case in point: 1157 LED bulbs. Bench tested alright but wouldn't work when installed. Turned out the contact pins were misaligned at the factory.
 

stubs300

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I have a 67 Chrysler Newport, I recently replaced the alternator with an OEM 55 amp alternator, and voltage regulator but it's only reading 11 volts. What am I missing here?

Why'd you replace them in the first place? Where'd you get the alternator from? I'd look at that first!
 

Chrome58

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I have the gauge wired in at the fuse panel running on a keyed power circuit. Regardless of whether it's at the alternator output or battery it shouldn't ever dip below 12 volts though.
Correct, but knowing the voltage reading at the alternator and at the battery might help to understand what's happening.
 

SuperDave

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Hey, we're all assuming the regulator receives power when the key is on. Check with a test light or multimeter that at least one of the wires on the regulator powers up, it could be that simple. If it doesn't, the field coils won't energize and no current will be produced.
424239-e82f350650b43ce45ef451ef5057b68e.jpg
 

SuperDave

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Next up, if the voltage regulator does see power, is it making it to the alternator? I know on mine, I had to replace one of the clips that goes to the field terminals, damned thing kept working its way loose and sliding off. If it happens ONE MORE TIME, I'm gonna hard solder the wire to the terminal permanently.

You may have to check continuity between the ends going from the regulator to the alternator with the multimeter set to ohms. It could very well be your last alternator and regulator were still good, problem was a bad wire or connection between the two. It is 50+ years old after all.
 
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FURYGT

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Did you buy one of these voltage regulators?

Mopar Voltage Regulator - Electronic Solid State with Correct Restoration Look | eBay

Have you made sure that the voltage regulator is properly grounded?

Details on the alternator. Rebuilt or New? Made in China? Single field or Dual Field?

Have you had the battery tested?

These days getting a new battery, alternator (especially a rebuilt unit) or a generic voltage regulator can be a 50/50 chance that it is defective.

Sending your alternator out to a local, quality alternator re-builder is always the best bet although not the cheapest. A good re-builder can also increase the amperage output.
 

Big_John

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I have a 67 Chrysler Newport, I recently replaced the alternator with an OEM 55 amp alternator, and voltage regulator but it's only reading 11 volts. I've checked all my grounds, and I don't appear to have any parasitic draws on the battery. It slowly gets weaker and after about a week of being driven it'll kill an 850 CCA battery. This is my second replacement alternator, and I've checked most of my wiring off the positive cable and it seems to be good without a bunch of corrosion. What am I missing here?
Just covering all the simple stuff...

Does the replacement alternator have two field connections by any chance? Most of the replacements I've seen lately seen to come through with the isolated field the later cars use and one field connection will need to be grounded for anything to work.

Gotta make sure all the bases are covered.
 

SuperDave

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Most of the replacements I've seen lately seen to come through with the isolated field the later cars use and one field connection will need to be grounded for anything to work.

Gotta make sure all the bases are covered.

How can you tell if it is or not? Do they look any different? And which lead goes back to the regulator? The blue, hot energized lead (hot to key/ballast) or the 2nd green lead? Are you supposed to tape one off and ground the extra field terminal?

Website documentation and/or pictures would help please.
 
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