Reply to "Similar problem as Albert with a twist"

Suburb Hi,

Try changing the voltage regulator here is why I state that you car is over charging the battery at 14.8 volts dc... Max is 14.5 VDC. you will burn up the battery at 14.8 all the time.

Here is what I know (some of what I know smile.)
normal charging rate of any car to properly keep the battery charged is 13.7 to 14.5 volts... Except as my late father would say below.

Hint... Measure the battery with a volt meter on DC ( which you did)
Then measure it on AC if you have a bad diode then you will produce an ac voltage, if it is shorted (what I call DC with an AC constant)

I will tell you this... My car which I have had for years, at idle, is under 13.7 volts closer to 12.7 but as soon as you give it gas it jumps to 13.9 to 14.2 Vdc. My dad came over on the boat from Italy and made his way thru life as an electronics tech (tv radio) he told me as long as you are charging 1 volt over the non charging battery voltage you are ok.

PS I installed a new alt and voltage regulator, and it did not change. I have checked every connection and termination. No Problems.
PS PS I am an Electrical Engineer.

As Forest says it could be a bad diode in the alt but the voltage relay is cheaper and easier to swap first.

Joe