C2 charging problem

[Noel B.]

I am having a charging issue with my 1966 roadster (327/300 PG AC). For five years my ammeter has read straight up as expected but recently it starting indicating an overcharge condition (+20 to +40) depending on RPM. I measured the charging voltage and it seemed too high (+16V) so I replaced the voltage regulator. Now the dash ammeter reads lower (around +8) at idle but still around +20 at 40 to 50 mph. Also at higher speeds the needle is bouncing back and forth rapidly as though the regulator is constantly trying to regulate the voltage with the relays. At some speeds I can hear a new buzzing sound. Any ideas?

[Leif A.]

Re: C2 charging problem

My first instinct would have been the VR, as well. Which unit did you replace it with...old school or new solid state? It's a simple enough task to pull your alternator and take it to your local parts house and have them check it out.

[Noel B.]

Re: C2 charging problem

I used an old school VR with relays (from NAPA)

[Leif A.]

Re: C2 charging problem

I used an old school VR with relays (from NAPA)

It, possibly, could have been bad out of the box.

[Edward J.]

Re: C2 charging problem

I agree with Leif, lot of parts are now made in China. since it not acting the same as the old one I think its not calibrated correctly. I would have the battery load tested to, just in case your dealing with a older battery that maybe over working the alternator and regulator. some of the parts stores like Auto zone will test your battery for free. just drive the car to them and have it tested while the battery is still in car.( much easier) on a C-2. Or if you have a local guy you trust.

[Richard G.]

Re: C2 charging problem

For five years my ammeter has read straight up as expected.

Amp gauge should go negative with the lights on and the motor off. And then go positive when the motor starts and slowly return to close to straight up as the battery charges. This is a good check of the gauge operation.

We need more information.
Check the voltages, at the battery, with the Corvette off and again with it running.

And yes I have seen them bad out of the box....
Rick

[Noel B.]

Re: C2 charging problem

Thanks guys! Before the problems my amp gauge behaved exactly as described by Rick. The gauge would go negative when lights were turned on and engine off. Then go positive on startup and then sit on zero while driving.

I measured some voltages at the battery:
Engine off = 12.71V
Engine running at idle = 12.57V
Engine revved to approx 1500 = 14.65V to 15V+ (lots of variation on my meter)

Also watched the ammeter:
Engine idle = +18
1500 RPM = approx +20 but bouncing up and down (I can hear the relay clicking)

I can certainly take the car to a shop on Monday and have the battery checked per your suggestions. It's only two years old....

One more thing. Just before the problem started I had the car at a tire shop and they left the key in the ACC position for a while and ran the battery down. It started up but I had to charge it when I got home. I have an aftermarket stereo in the car that is on in the ACC mode.

Hope this helps. Thanks for your guidance.

[Mark E.]

Re: C2 charging problem

Noel,

This car does not have an ammeter; it's a "battery" gauge which measures voltage differential. The high reading on the gauge indicates a high voltage differential between the solenoid and regulator. This may be because the alternator is charging, but either the battery is not accepting the charge or it's not receiving the charge.

So assuming the battery gauge is working ok, I suspect the battery, a bad ground or bad electrical connection in the charging system.

I'd start by checking connections at the battery, starter solenoid, junction block, voltage regulator and alternator- including grounds. Make sure they're clean and tight.

Then try another battery.

Let us know what you find so we can learn.

[Noel B.]

Re: C2 charging problem

I checked the connections and ground continuity and everything seemed OK. This morning I went to the local NAPA parts store and had them test the system. They found that the battery was OK but that the alternator was bad. So I ordered an alternator which will take a few days. Maybe by the end of the week I can install it and try it out.

Thanks for your guidance.

Noel

[Leif A.]

Re: C2 charging problem

I checked the connections and ground continuity and everything seemed OK. This morning I went to the local NAPA parts store and had them test the system. They found that the battery was OK but that the alternator was bad. So I ordered an alternator which will take a few days. Maybe by the end of the week I can install it and try it out.

Thanks for your guidance.

Noel

Noel,
Is your current alternator date correct for your car? If so, I would certainly have it rebuilt...local alternator/generator shop can handle in a day for less than a rebuilt. Also, if you're not going for date correct stuff, I would ditch the old style VR and go with a solid state unit (Wells VR715). You can, also, use the guts of the VR715 and the cover from your Delco VR to make it look more period correct. Just some thoughts.

[John D.]

[Noel B.]

Re: C2 charging problem

Where can I purchase a Wells VR715? I may try this.

[Leif A.]

Re: C2 charging problem

Where can I purchase a Wells VR715? I may try this.

Auto Zone under their Duralast brand name, for one.

[Noel B.]

Re: C2 charging problem

I ran into a mystery when installing the new alternator. Since the old two-wire alternator connector was corroded I purchased a new one. When I went to install the connector on the new alternator I noticed that the blue wire on the new connector would go to the R terminal. This seems backwards since the blue wire from the regulator is marked F and should go to the field side. It looks like I have to cross connect the wires (blue to white) to make a correct connection to the alternator. Any ideas?

[Donald H.]

Re: C2 charging problem

In my 67, the blue wire on the alternator plug goes to F on the alternator
and to F one the VR