Over charge with rpm input

1 Get a meter on the battery and see what it's actually doing

If it's running too much voltage IE over 14.5V

2 Make sure the battery is charged and have it tested

3 Key on, engine off, measure voltage drop from alternator field to battery positive post. You don't want to see more than .2-.3V (three tenths of a volt)

Fire up engine, fast idle, get battery "normalized" IE ammeter satisfied, recheck battery voltage. If it's high, check the regulator ground

To do that, put one probe on battery neg post, the other onto the regulator frame. Be sure to stab through any rust/ chrome. You do not want MORE than .2v (two tenths)

If all the above is checks OK but the charging voltage at the battery is still high, replace the regulator

Optimal charging voltage with engine/ regulator warm, battery "normalized" is 13.8--14.2V Absolute limits are 13.5--14.5. Above or below you have troubles.