When you're out and about in your vehicle, the last thing you want is to get stuck with a dead battery -- especially in the dead of winter, in the middle of nowhere. Here's what to look for in car batteries, and how to choose one that's "fresh." When making a purchase, the three most important things are getting the right size, getting sufficient cold-cranking amps to be able to start in cold weather and being sure the battery you buy is fresh (less than six months old). How can you tell? Somewhere on the battery, either on a sticker or stamped into the case, you'll find a serial number. The first two characters tell the date it was made. Most start with a letter -- "a" is for January, "b" for February, and so on. The second is a number that tells the year. For example, "4" is 2004. So, "c-4" would be March 2004. Learn the code -- and hit the road!