how to check if my Volvo XC90's battery is good or bad?

Solution

1. Preparation

• Tools Required: Multimeter, load tester, hydrometer (if applicable), wrench set, battery terminal cleaning brush.
• Wear safety goggles and gloves to protect from battery acid.

2. Inspect Battery Terminals

• Sub-steps:
  1. Ensure the vehicle is off and the keys are removed.
  2. Open the hood and locate the battery.
  3. Check the terminals for corrosion (white, ashy residue) and clean them with a terminal cleaning brush.
  4. Ensure the connections are tight; use a wrench to tighten if necessary.

3. Check Voltage

• Sub-steps:
  1. Set the multimeter to the DC voltage setting.
  2. Connect the red probe to the positive terminal and the black probe to the negative terminal.
  3. Record the voltage reading. A healthy battery should read around 12.6 volts or higher.

4. Perform Load Test

• Sub-steps:
  1. Connect the load tester to the battery terminals following the manufacturer's instructions.
  2. Apply the load for about 10-15 seconds.
  3. Observe the voltage drop; it should not drop below 9.6 volts at 70°F (21°C) under load.

5. Physical Inspection

• Sub-steps:
  1. Look for any visible damage such as cracks or bulging in the battery case.
  2. If any damage is found, the battery should be replaced immediately.

6. Check Specific Gravity (Optional)

• Sub-steps:
  1. If the battery has removable caps, use a hydrometer to draw a sample of the electrolyte from each cell.
  2. Compare the specific gravity readings against the manufacturer's values to assess the health of the battery.