72 overcharging
The only thing that I did was to clean the cables and terminals really good when I put my good battery back in.
Making better connections can make a difference!
I'd still check the connection coming off the alternator and the other end of it.
If you are seeing 14 volts or more, power is flowing from the alternator.
If there are voltage drops between the alternator output and the regulator "I" terminal, the regulator will regulate based on the lower voltage it sees.
Lets say the internal set points for the regulator are 14.2 to 14.8 V.
And lets say after start up the alternator is producing providing 15 amps to recharge the battery and run the field and ignition.
If resistance to the 15 amps flowing through the wires and connections causes a 0.5 Volt drop before the regulator I terminal, the regulator will boost the field until the I terminal sees 14.2 to 14.8 Volts. Being the air is cold, that could be 14.8 V at the regulator, bring the alternator output ot 15.3 Volts.
(Neither the regulator nor the battery sees that 15.3 volts.)
As the battery charges, the current drawn drops quickly. When the battery is charged and nothing else is running, alternator will only provide 4 to 5 amps for the ignition and field.
With only 5 amps flowing, voltage drop caused by resistance in the wires and connections goes down. Now maybe its only 0.2 Volt drop.
Make sense?
Voltage drop seen by the regulator depends both on the routing, and the amount of current flowing.
