I have a 1999 Cadillac STS that required a new battery, which was replaced by a AAA service technician. The battery terminalsand cables were not cleaned when the new battery was installed.

The car requires a Series 79 battery. However, the technician replaced the battery with a Series 78 battery, which is smaller as I understand.

Since the battery was installed, the voltage regulator in the alternator has gone bad and a sensors burned up requiring about $1,500 in repairs to the car. The old battery was apparently leaking and may have contributed to the problem.

My question is could the Series 78 battery have caused the damage to the alternator and/or sensor. If so, how much could it contribute to the damage...aprtially, or in total?

Thank you.

 

The series number reflects battery dimension, not power. So you need to compare CCA between the two. If the 78 battery has the same or higher CCA, then it has no effect on the electrical system. The regulator is most likely the culprit here. Could have led to the first batterys failure as well as whatever module failed. So, no. I doubt if this new battery has any real effect.