whats a good battery to buy?

One thing that I make sure to do is always go out and crank anything that has a battery every three weeks. I don't think that a battery setting for a couple of months would last to long. But who knows. Batteries sit for longer periods of time before they sell but they aren't connected up either. I would suggest either cranking the car more often or get a battery tender. Also buy a disconnect that mounts at the battery for the negative terminal. I would do both if I was having battery trouble.