Alternator overcharging?

Question

What would cause an alternator to overcharge? and will it drain your battery?

Answer 1

It all depends on the type of alternator.  Most have a regulator that will cause the problem of overcharging or undercharging, some have IC boards.  If an IC board fails it could drain the battery, however very unlikely.  When you turn your key off it turns off power to one of the alternator wires that controls the field or IC board to prevent them from draining your battery.  

Also check that it isn't your gage.  Get a voltmeter and with the engine running verify the voltage at your battery.

Answer 2

a bad regulator will cause one to over charge like that,or even a loose ground wire will make one try to keep charging the battery ,you  may need to take the alternator and have it checked because most alternators these days have built in regulators on them,good luck.

Answer 3

If your alternator is overcharging, it would be a defective voltage regulator. This will cause the alternator to run constantly. This will not drain your battery, it's actually providing too much power to it. This will damage your battery as well by overcharging. To see what exactly is going on a amp-meter will be needed. Sometimes your local parts store will perform these tests for you for free. It's worth the call.