GM Service Manual Online
For 1990-2009 cars only

Certain electronic devices on the vehicle maintain a small continuous current drain or a parasitic load on the battery. A battery that is not used for an extended period of time will discharge. Eventually permanent damage will result.

Battery Protection During Vehicle Storage

In order to maintain the battery state-of-charge while storing the vehicle for more than 30 days perform the following actions:

  1. Verify that the green dot is visible in the built-in hydrometer.
  2. Disconnect the battery ground negative cable in order to protect the battery from discharge by parasitic current drains.

When the battery cannot be disconnected, perform the following actions:

  1. Maintain a high state-of-charge.
  2. Establish a regular schedule for recharging the battery every 20-45 days.
  3. When a battery is found without a green dot visible in the hydrometer, refer to Battery Hydrometer Displays Dark or Yellow Dot .

A battery that has remained in a discharged state for a long period of time is difficult to recharge or may be permanently damaged.