For 1990-2009 cars

If you're not going to drive your vehicle for 25 days or more, disconnect the black, negative (-) cable from the battery. This will keep the battery from running down.

At any time when your vehicle is not in use, turn the ignition key from the "ACC" position to the "LOCK" position and make sure that your fog lamp switch is in the "OFF" position (if equipped). Then remove the key. This will also help keep the battery from running down. Contact your retailer to learn how to prepare your vehicle for longer storage periods.