Overcharge?

1969 RR took it out the other day and as it was warming up the amp meter spiked and wouldnt come down. I figured a voltage regulator because it has happened before. Replaced it with a really good quality standard part. Made in USA. Replaced it and same thing is happening. Un hooked the battery and the car actually revs up to 4 grand and the gauges start to spike. So I hooked up the battery and parked the car again. Once it was off I unhooked the battery. Is it a junk alternator? Or am I going to be chacing grounds for a short?

you probably need to confirm a few things first.
check the voltage at the sensing wire for the voltage reg, the car can be in run, but doesn't have to be running.

see how close it is to the battery voltage.

use the battery for ground on battery, but use the case of the voltage reg for ground when you check voltage there.

if there is a difference then use the battery as ground and see if it goes away.
if not then I would be looking at the bulkhead connector and tracing it back to the ignition to see where you lose the voltage.

if the difference went away when you changed to battery ground, then the vr isn't grounded properly.

If it matched battery voltage, and you know this vr is good, then I would be getting the alt tested.

Thanks I'll go check it out!

Have you tried swapping batteries. Yours may have an internal short. Besides it's an easy check.

Once I got an intermitent short on my alt able to get between 18 up to 24 volts depending on RPMs... but without load, so I disconected the batt and engine died. It was one of the rotor vent vanes getting in touch with one of the stator leads on every spin.

BUT... the engine never increased the RPMs by itself. Just sharing one misterious experience I had

when I've had overcharge issues it's always been the voltage regulator had a poor ground. anymore I run a pigtail off the regulator and ground it to the block.

Another easy check is unplugging the field wire at the alternator. If you are still max charging then you have an internal alternator short from the field to ground. This happened to me recently - I havent take the alternator apart yet but the pulley side bearing is so worn you can move the shaft around. good luck

The only thing I would add to AndrewH's suggestions is to note whether the Ammeter 'charging' followed the rpms from slow idle to 1500 rpm.

When you post back, if the problem is not resolved, tell us if this is an unaltered factory system.

On the electronic reg with dual fields the car wont charge if the reg is not grounded since that's the field ground. Course you may be talking of the older mech regulator only ? Working many years at a Dodge dealer I found the two wire connector on the electronic reg would loose its connection at the reg for the batt sense wire but the field wire still had a good connection and of course it would overcharge without knowing batt volts. Unhook the field wire or wires depending on your reg and see if it stops charging like was said. Ron

Went out to do more checking and everything seems to check good. I didnt not unhook the regulator to see if it stops yet. However it keeps saying overcharge with the rpm increase. I put my volt meter on the battery top posts. As I rev the engine it goes up to 14.4 or 14.5 and stops there when its revving up. Yet the amp meter inside pegs all the way to the right to the point where it bounces. Possible worong in dash issue or does it still sound like an alt or battery issue?

that is odd and doesn't really explain the reving when the battery is unhooked.

can you see the meter and gauge at the same time?

I agree^^^^^

Is this 100% factory wiring?
No electic fans, fuel pumps, winches.. ?

If so, my first suspicion would be the battery. if its in low state of charge, or has a plate detach, it would suck current like crazy.
Second suspicion would be some sort of short. Maybe cross wire or maybe with chassis. The fact the instrument gages are sometimes effected really has me concerned about that.
There were some options that drew power from the battery side of the ammeter. I think some years/models a clock option was tied in there.

If the battery has a shorted plate it will still show 14.5 Volts but be taking all the Amps the alt can push thru the Amp gauge.

Use all safety gear around battery acid.
I'd check to see if you have 2.5+ volts in each port of the battery.
1.Unscrew all filler caps on the battery.

2. Put the BLACK Neg cable of your VOM on the battery's Neg lug. Put the RED Pos cable of the VOM into the acid of the first hole. Should be 2.5 to 2.7 Volts DC. Yes, into the acid. You do not need to touch the lead plate inside.

3. Move the cables of the VOM up a hole and measure.... Rinse and repeat. Should be balanced at all holes.

I’ve been working with automotive batteries for 50 years. You haven’t a clue about what you are talking about.

50 years wasted

http://constructionmanuals.tpub.com/14273/css/Battery-Voltage-Test-40.htm

I have seen this a few times in my 40 plus years as a tech. Battery cell problem where the volts wont go over a certain amount usually from about 13 to 14.5 but put an ammeter in series in the alt output wire and the alt is putting out all it can. I have seen well over 50 amps on cars with alt's that high of amperage and yet the battery volts wont come up enough for reg to cut alt amps back. You have to hook an ammeter up along with a voltmeter to properly diagnose that problem. Put a new battery in and problem solved. But I never checked each cell that way though. Usually a good battery reads about 12.6 or 2.1 volts per cell. Ron

So you agree with his post? 2.5-2.7 volts per cell and you don’t touch the plates? Really?

I'm soooo sorry I got it 0.4 volts wrong. You are soooo right. You win the prize for the day.

But just try doing the test and see if you get between 2.0 to 2.2 volts in each cell.

Not sure who PI$$ED in your Cornflakes this morning.

So took the battery in and it tested good. Guess it time to pull the alternator and have that tested

The batter yis fully charged?
What were the results of checking for voltage differences? (see post 2)

No need to disconnect the regulator.
Just measure the voltage the regulator is 'seeing'. That's the 'ign' terminal.
After that, check the voltage at the alternator output stud.
Compare with voltage at the battery positive.
Best done while running.

This is the basic circuitry.
1969 the feed to the key switch is probbaly red insulated, and the 'run' wire may go to the regulator and then to the ballast, but it works the same.

Three possibilities for high charging on the ammeter.
1. Battery is very low on charge.
* If a battery is really low on charge, given power at 14 Volts, it could draw 40 amps if the alternator can provide.
* At idle the alternator may struggle to provide that much power - hence the the drop in voltage and current.
2. High resistance in the circuits results in the regulator 'seeing' a lower voltage when more current is flowing.
* If the regulator 'sees' a low voltage, it lets more current through to the rotor. The Alternator Output might be a t 16 V while the regulator only 'see' 14 V.
* Checking each of the connectors is a good place to start. The ignition switch can also have excessive internal resistance.
3. Something else is drawing current on the battery side of the alternator.
4. The ammeter is reading wrong. It's a very simple device so unlikely but its possible. Small magnetic fueld created by the electric current deflects the needle. Easy enough to verify with a clamp meter if all else is ruled out.

Alternator was bad and had an internal short causing a high amperage back charge. All good and back on the road.

Thanks for the update It's always nice to know the outcome for those who tried to help as well as those that didn't

updates, especially good ones, are great to know !
even old dogs [like me !] sometimes [really ? i forget a lot anymore !] need a memory jog or three ! [ i need the "or three" treatment ! ]
glad it worked out for ya !