My zl1 is over four years old with the original battery. I’ve gone up to five weeks between starts in the winter without any problems starting the car. I’m in Florida until April so I did put the battery on a trickle charger before I left. I firgured between the age of the battery and length of time I’ll be gone, at trickle charger would be a worthwhile investment.
This is the one I bought.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1