I have 91 BMW E30 which I put a new battery into because the previous one was really old. However shortly after that, I kept it stored away for about a year or so. Recently I jump started it and drove it for a good 20 mins or so. The next day the battery was completely dead again. Tried again, jump started it, drove it for another 20 mins, let it idle for a bit, turned it off. I waited about 10 minutes or so, and tried starting it, but it wouldn't even crank. So, I guess it might be my alternator, or maybe just a bad battery? Thank you!
Searches related to Will a car battery go bad if it remains in the car for a long period of time without being driven?
how long can a car sit without being driven
how long can a car sit before the battery dies
leaving a car unused
how long can a car sit before engine goes bad
leaving car for 1 month
not driving car for a month
how long can a car sit without being started
how long can a car sit without starting