Quote Originally Posted by dr. d View Post
our spare car isn't touched for 2-3 weeks at a time.
then we use her one day on our regular route.
several years already.
"no battery issues."
For the most part, if you have a relatively healthy battery, it should survive weeks with minuscule to no parasitic draw. But that doesn't mean the battery didn't lose some of its health in the process. Sulfation just creeps up until it reaches a critical point.

It's why a battery on its last leg would suddenly die after being left unused for a few days or even just a few hours.