Will A Bad Alternator Ruin A New Battery. A bad alternator can ruin a good battery and a bad battery can ruin a good alternator so forget trying to get away with either one. Depending on what has failed in the alternator several paths could develop.
The answer is that a bad alternator does not always affect the car battery especially if the battery is new. If you have a fairly new battery you can usually get away with it once maybe twice. The alternator can have a bad diode which allows AC to flow to the battery.
Overcharging the battery too high of voltsge causing premature cell failure 2.
Then while the engine is running take away the negative battery terminal cable from the 12V battery. Frankly speaking this period can vary depending on many factors but I highly recommend getting a new alternator unless you want to spoil a battery as well. First you need to check the condition of the battery. It is because it is responsible for powering all the electrical equipment of the car along with charging the battery of the car while the engine of the car is.
