Over charging

[Pappy]

Howdy folks,
67 fury III rebuilt 383/727.
At idle its charging 15 to 18 volts.
Rebuilt alternator solid state regulator with dedicated ground wire from mounting bolt to negative battery cable and chassis ground.

Anxious to get it out on the road but dont want to burn up the battery.
I can rebuild engines, swap suspension components and brakes but electrical has always been a mystery.
TIA!

 

[live4theking]

Someone with better background will surely chime in, but to me it sounds like your regulator is not doing it's job.

 

[mopar440]

How are the battery cables? Any resistance can cause overcharge. Resistance in the bulkhead too

Try the under hood ammeter bypass, there is a thread on it

 

[Davea Lux]

Sounds like you have a defective solid state regulator. To be throwing a constant 18v it has to be stuck in the full charge position. It could also be that the battery is not accepting a full charge, this will also cause the regulator to try and keep charging a bad battery. Run a voltmeter test on the battery at rest and see what voltage the battery is putting out if you are getting 13.2 volts or more at rest the battery is probably ok and the fault lies with the regulator. As noted above, be sure the battery cables are clean and tight on the battery.

Dave

 

[cbarge]

Your alternator...single field or dual??
How many amps??
Factory may be 38 amps most replacements are higher and you must accomodate the system for the added power

If dual make sure you ground the unused field to the alternator housing.
If single field alternator swap out voltage regulator.
Please do the underhood ammeter bypass!
At 18 volts you can burn up the car.

 

[Pappy]

How are the battery cables? Any resistance can cause overcharge. Resistance in the bulkhead too

Try the under hood ammeter bypass, there is a thread on it

Battery cables are brand new, as is battery. confirmed connections are clean and tight. new ground wire from engine to firewall.
will perform ammeter bypass. THX

 

[Pappy]

Someone with better background will surely chime in, but to me it sounds like your regulator is not doing it's job.

thx, its a new regulator purchased from furygt last week. old regulator was performing the same.

 

[Pappy]

Your alternator...single field or dual??
How many amps??
Factory may be 38 amps most replacements are higher and you must accomodate the system for the added power

If dual make sure you ground the unused field to the alternator housing.
If single field alternator swap out voltage regulator.
Please do the underhood ammeter bypass!
At 18 volts you can burn up the car.

thx for responding.
Battery cables are brand new, as is battery. confirmed connections are clean and tight. new ground wire from engine to firewall.
dunno about alternator - its rebuilt. will investigate.
old regulator did the same thing so i purchased thee new one from a member here.
yes, not driving the car until this is resolved.
will perform that test.
will perform ammeter bypass. THX

 

[70bigblockdodge]

According to what guage is it at 18 volts? Did you verify with a multi-meter?

 

[stubs300]

thx, its a new regulator purchased from furygt last week.

Oh boy, here we go again with this! There's plenty of discussions about the problems with these. If your not anal about originality, just upgrade to the newer large better style regulator? Here's some tech info if needed. Good Luck
charging system overview

 

[Pappy]

According to what guage is it at 18 volts? Did you verify with a multi-meter?

sorry i didnt include that detail. factory gauge reads clear to the right. aftermarket amp gauge reads 16 to 18. voltmeter on the battery reads 13.3 before starting then 16 to 18 when idling.
thx.

 

[70bigblockdodge]

Oh boy, here we go again with this! There's plenty of discussions about the problems with these. If your not anal about originality, just upgrade to the newer large better style regulator? Here's some tech info if needed. Good Luck
charging system overview

No, alternator is the same single or dual field. This is why you can take a dual field, ground one side and it works for single field. You could do the opposite, but they buried the ground in the case so it becomes too difficult. So no upgrade there. Mechanical point regulators can be a problem, this is solved by solid state ones that are retro fit in 69 and earlier, good ones sold by @FURYGT.
The dual field can provide a more constant voltage, not more voltage just more consistent. GM did very well with single field internally regulated alternators for many years. No need to overcomplicate things, and upgrade for no reason.

 

[Pappy]

Oh boy, here we go again with this! There's plenty of discussions about the problems with these. If your not anal about originality, just upgrade to the newer large better style regulator? Here's some tech info if needed. Good Luck
charging system overview

since there is no "FIELD -" connection on the alternator, can i hook a new wire to that bolt on the alternator and route it to the newer regulator -or- do i need to replace the alternator with a 1970+ model?

 

[Pappy]

No, alternator is the same single or dual field. This is why you can take a dual field, ground one side and it works for single field. You could do the opposite, but they buried the ground in the case so it becomes too difficult. So no upgrade there. Mechanical point regulators can be a problem, this is solved by solid state ones that are retro fit in 69 and earlier, good ones sold by @FURYGT.
The dual field can provide a more constant voltage, not more voltage just more consistent. GM did very well with single field internally regulated alternators for many years. No need to overcomplicate things, and upgrade for no reason.

the new regulator did come from @FURYGT.
installed it this morning. old regulator (from Sears) was performing the same way.

 

[70bigblockdodge]

sorry i didnt include that detail. factory gauge reads clear to the right. aftermarket amp gauge reads 16 to 18. voltmeter on the battery reads 13.3 before starting then 16 to 18 when idling.
thx.

If you disconnect the field wire on the alternator, what does it do?
Should be approximately same 13.3 before starting. Dash amp guage should return to center/ slightly left on discharge side.
Or just try the simple pull the positive battery lead while it's running. You have a problem that sure as hell sounds like the regulator full fielding the alternator. With 2 different regulators doing this? it sounds like your getting 12 volts into the green field wire short from another wire.

 

[70bigblockdodge]

the new regulator did come from @FURYGT.
installed it this morning. old regulator (from Sears) was performing the same way.

Are you sure the regulator is wired correctly. Blue wire is ignition input, this is the supply to pulse the voltage in the green field wire to excite the alternator into producing a charge. I'm not sure what happens when you connect them backwards, but I'm going to assume since the supply side sees low voltage it would close/pulse alot causing the alternator to overcharge.

 

[Sixpactogo]

This subject comes up all the time. People like to blame the alternator or the battery. A working alternator will put out close to 20 Volts. A good battery will accept what ever the regulator tells it to but will not take it forever. The job of the regulator is to keep the voltage constant at around 13.8 - 14.4 Volts referenced to ground. If the regulator case is not properly grounded, it can give a false reference to ground and could be causing the voltage to be too high. Grounds by far, cause more electrical gremlins in our old iron because of the corrosion caused by old age and bad maintenance. Get a digital meter, put it on ohms, and start checking for good grounds by hooking one lead to your negative post with the negative cable connected. The other lead to engine block, Alternator case, regulator case, firewall, dash frame, and any place else that should be grounded. Paint does not offer a good ground. If you read more than .3 ohms you can blame it on paint, corrosion or loose connections. If the regulator case is properly grounded and you are charging the system at 18 volts, rest assured the regulator is not doing it's job. It could be because it is NFG or does not have a good reference to ground.

 

[4spd300J]

Also check the condition of the alternator wiring harness. I had a slant six Dart that the harness had worn through on a corner on the back of the head. The two field wires were contacting each other, the ammeter was pegging and I've never seen headlights as bright as these got.

 

[65sporty]

I would start checking the wiring like the guy's suggested, pic's go a long ways to helping with what you have going on. Wiring at alt, regulator, etc I am sure you get the picture.

 

[FURYGT]

PM sent.