Perform a complete battery test to determine the state of charge, cranking voltage, and overall battery health using a battery tester or multimeter.

Warnings

Tools required

Preparation

1. Park vehicle on level ground and turn off engine
2. Turn off all electrical accessories including radio, lights, and climate control
3. Allow engine to cool if recently driven
4. Open hood and locate battery in engine compartment on driver's side

Procedure

1. 1

   Inspect battery condition
   Visually inspect the battery for obvious damage, cracks, bulging case, corrosion on terminals, or loose connections. Check that the battery hold-down bracket is secure. Note any white, green, or blue corrosion around terminals.
2. 2

   Clean battery terminals if needed
   If corrosion is present on terminals, loosen the negative (-) terminal bolt first using a 10mm wrench, then loosen the positive (+) terminal bolt. Remove terminal clamps and clean both battery posts and cable terminals with a wire brush. Reconnect positive terminal first, then negative terminal.
   Torque spec

   Battery Terminal Bolts6 Nm (5 lb-ft)
3. 3

   Perform static voltage test
   Set multimeter or battery tester to DC voltage. Connect red probe to positive (+) terminal and black probe to negative (-) terminal. Record voltage reading. A fully charged battery should read 12.6V or higher. 12.4V indicates 75% charge, 12.2V indicates 50% charge, and below 12.0V indicates discharged battery requiring charging before further testing.
4. 4

   Perform cranking voltage test
   With tester still connected to battery terminals, have an assistant turn the ignition key to START position and crank the engine while you observe the voltage reading. Voltage should not drop below 9.6V during cranking for a healthy battery. If voltage drops below 9.6V, battery may be weak or failing.
5. 5

   Perform load test (if using load tester)
   If using a dedicated battery load tester, apply a load equal to half the battery's CCA (Cold Cranking Amps) rating for 15 seconds. The 2015 Forte 1.8L typically uses a 550-600 CCA battery. Apply approximately 275-300 amps load. Battery should maintain at least 9.6V at 70°F (21°C) or above during the test. Lower temperatures require different minimum voltages per tester instructions.
6. 6

   Check charging system voltage
   Start the engine and let it idle. Measure voltage across battery terminals with engine running. Voltage should read between 13.8V and 14.7V, indicating proper alternator function. If voltage is below 13.5V, charging system may have issues. If above 15.0V, voltage regulator may be faulty.
7. 7

   Evaluate test results
   Compare all test results: Static voltage indicates state of charge. Cranking voltage indicates ability to deliver current under load. Load test indicates overall battery health. Charging voltage indicates alternator performance. If battery fails any test (low static voltage after charging, cranking voltage below 9.6V, or failure to hold load), replacement is recommended.

Reassembly

1. Ensure battery terminals are tight and secure to prevent voltage drops or starting issues
2. Apply dielectric grease to terminal connections if desired to prevent future corrosion
3. Verify battery hold-down bracket is properly secured

Verification

• Confirm battery terminals are clean and tight with no movement when wiggled
• Verify static voltage reading is appropriate for battery charge level
• Start vehicle to confirm normal cranking speed and successful start
• Check that all electrical accessories function normally

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