A battery will not hold an overcharge.
First, you need a voltmeter.
With everything shut down, engine off, you should have a reading of 12.8 Volts at the battery posts
With the engine running and alternator charging, you could see up to 14.2 Volts at max. charging rate.
If you have more than 14.2 Volts, your alternator (Voltage regulator) is defective.
Easy and cheap to replace.
JackD