Ammeter Battery overcharge

I assume you are driving with "high voltage "? A problem like that needs immediate attention.

My guess is 5 hours of driving would have cooked the battery. The problem might be poor bulkhead connections. That is checked by using a voltmeter and measuring voltage at IGN terminal with engine running. If it is about 13.8V, but battery voltage is higher (^14.2V) , the difference is the voltage drop. The drop should only be a few tenths. The regulator tries to regulate the voltage at IGN, by switching the field on as necessary. Since the alternator delivers the power connectors, thru the amp gauge and back to battery, voltage drops there result in the alternator voltage running high, to achieve the desired voltage at IGN.