GM Service Manual Online
For 1990-2009 cars only

Some electronic devices on the vehicle impose small continuous current drains on the battery. This is commonly called parasitic load. If the vehicle is not used for an extended time, these parasitic loads can discharge and eventually cause permanent damage to the battery. Discharged batteries can also freeze in cold weather. Refer to Electrolyte Freezing .

To help keep the battery in a charged state while storing the vehicle, follow the following steps:

  1. If the vehicle is likely to be stored for over 30 days, make sure the green dot is visible, then disconnect the negative battery cable at the battery. Refer to

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

    in General Information. This will protect the battery from being discharged by parasitic current drains from the vehicle's electrical system. When it is time to reconnect the battery:
  2. 1.1. Use a wire brush to lightly clean any oxidation from the contact face of the battery terminal before reattaching the cable.

    Tighten
    Tighten the battery cable bolt to 10 N·m (89 lb in).

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

    1.2. Reset the clock, pushbutton radio tuning, etc., before the vehicle is put back into service.
  3. If the battery cannot be disconnected, establish a regular schedule of recharging the battery 20-45 days to maintain a high state of charge. Any time a battery is found with the green dot not visible in the hydrometer, promptly recharge the battery.
  4. To keep charge time low, use a battery charger that is capable of providing a charging voltage of at least 16 volts. Original equipment maintenance free batteries will not be damaged by charge rates of 50 amps or more, as long as the battery does not spill electrolyte from the vents, or get too hot over 52° C (125° F). Every 45-60 minutes, check the battery being charged and stop or reduce the charging rate if necessary. To avoid overcharging, stop charging within one hour after the green dot appears in the hydrometer.
  5. Allow ample charging time. A battery that is allowed to remain in a discharged state for a long period of time will be difficult to recharge, and may even become permanently damaged if allowed to stay discharged. Refer to Battery Charging.