What damage can be done by the alternator over charging?

run the fault codes to find out if any damage was done when the battery was disconnected while running
It is an alternator , not a generator and doing what you did is a good way of damaging the whole charging system

voltage regulators are tested with a volt meter and an amp meter and is done by a qualified auto electrician. so instead of running the risk of damaging the alternator rectifier and regulator have it done professionally

Did not list any year/model info, however-
-have alternator output checked. if not charging:
possible alternator not charging-replace alternator
possible corroded or damaged positive battery wire to alternator
faulty ground wire
alternator fuse or fuse link blown
engine's idle rpm below 800

Taking the battery off when car is running causes voltage spikes that can damage electronics, so it is strongly recommended that it not be done. Possibly, there is a fusible link blown out. It would be between the alternator and battery, keeping the alternator from charging the battery, and keeping it from powering the electric system.

Sounds like you need to go to a different mechanic!! First things first. Your Battery is probably in a very low state of charge. This is why you can only drive a few minutes before it dies. A fully charged battery will give you much more driving time than 8 minutes. Now what you need to do is have the battery brought up to full charge. Once this is done then the charging system can be checked accurately. Keep in mind if the battery is in a low state of charge the alternator can be damaged because it has to work very hard to try to charge the battery. This may explain the frequent failure. If the charging system is ok then a key off draw test should be performed. You may be draining the battery when the vehicle is off due to a draw on the battery. Lastly if the quality of the alternator that is being put in your vehicle is substandard this may be a problem as well. All aftermarket parts are not equal!! If the alternator needs to be replaced then be sure to put a quality brand in your car. Make sure the battery is fully charged before doing so as not to damage a new part. Although charging system problems are fairly easy to diagnose the mechanic doing it must be fully trained in doing so or repeat failures are guaranteed. Hope this helps

ALTERNATOR DRIVE BELT SLIPPING OR BATTERY CABLES NEED REPLACING IF THEY ARE THE ORIGINAL ONES.THE VOLT GAUGE COULD BE FAULTY.TO TELL GET A DIGITAL VOLTMETER HOOK TO CAR BATTERY CRANK CAR UP.BATTERY VOLTAGE SHOULD BE 13.5 TO 14.5 VOLTS. WITH NEW CABLES. IF NOT CHECK ALTERNATOR FIELD WIRES FOR DAMAGE ALSO ALTERNATOR POSITIVE WIRE FOR DAMAGE.

The instructions for installing a new alternator usually read to fully charge the battery (12.3 - 12.8 volt range). Otherwise, the alternator will be damaged when it initializes. I have seen some extreme damage result from installing a new alternator with a low-charge battery. The torque required to turn an alternator when damaged in this scenario is unbelieveable!

No, not unless the alternator is very small and you have a large battery that is well down in charge. The ideal alternator to battery size is 25%. This means that if the battery is 100 amp hour in size it should have at least a 25amp alternator. The problem only really arises in an RV or boat where a large house battery bank has been installed but the alternator size has not been addressed to cope. The damage done would be caused by an alternator working too hard and over heating.

the alternator is still not charging be sure to check all the grounds on transmission and be sure the plug that goes into alternator is not melted or damaged you may have gotten a dud alternator some aftermarket rebuilds are **** please rate -jeff