Over charging
 

Upon charging, the amp gauge goes to 15 and stays there. The battery is always on a tender and is fully charged but the amp gauge never moves off 15 amps (unless turned off when it goes to zero). I installed a new alternator and same situation. I am afraid it will over charge the battery. Any ideas?

Yes, constant overcharging will ruin the battery. Does your alternator have a internal voltage regulator or a separate VR box?

Embarrassingly I do not know. When I had this problem, a new alternator was just installed and the problem continued. I need to take a picture of the alternator and check out the part number which may answer the question. There is only one wire attached to it and you can see where 3 smaller wires are not connected and been cut. I do not know if that tells you anything.

Thanks

It has an internal voltage regulator. the stock voltage regulator has been disconnected.

Do you have a manual with electrical schematics and the use of a common hand held volt meter? I’d check first at the voltage regulator to see the output and whether your gauge is reading correctly. If this is above your pay grade I’d recommend taking the car to this shop local to you. They are very good and will sort things out for you.

https://www.motorcars-service.com

First of all, does your car have a voltmeter or an ammeter? If it's an ammeter, have there been any other wiring mods?

To check on the meter, you should use a digital voltmeter (DVM), a twenty dollar tool available at any parts store. Anyone who owns an old car should have a DVM in their kit. Start the car, set the DVM to measure DC voltage, and measure across the battery terminals. Anything more than 15v would require investigation.

I stand corrected, it is a voltmeter. With ignition on and car not running the meter registers 12 v. When engine running it goes to and stays at 15 v. Is the fact that it never drops below 15 v while running a concern? I am going to pick up a new DC digital voltmeter and follow your recommendations. Thanks

You need to check with a DVM. It could just be the gauge.